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NICK WONG: Hello.

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So my name is Nick.

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And this is CS50 seminars.

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I'm going to be covering a
little bit of web development.

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I think the title of this seminar is
Basics of Web Development with Python

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and Django.

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Unsurprisingly, we'll be
using Python and Django.

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To say this is the
basics of web development

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is probably an overstatement.

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It will be a very, very brief
dive into web development.

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And I get about an hour.

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And I'm going to try and cover
as much Python, as much Django,

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and as much web development as I can.

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Currently, we are looking at
my beautiful screen saver.

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I'm a huge fan.

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I didn't write it.

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It's basically just
borrowed from The Matrix.

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I was recently told
that The Matrix actually

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used a Japanese cookbook's characters, I
think, for the things that come across.

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I am still in trying
to get that to work.

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But we're going to just dive right in.

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So if you wants to see some code,
if you go to this GitHub repository,

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I've built a bunch of stages for the app
that we're going to be building today.

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I'm going to talk a little bit about
what Django is, why I like using it,

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some of the frameworks
and ideas behind it.

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And then we're going to go
right into just kind of seeing

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how that kind of all comes together.

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I'm luckily not going to be doing
a whole lot of live coding today.

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Live coding is one of the
banes of my existence.

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I hate it.

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I will never, ever successfully
live code entirely.

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I think I spend most of it debugging.

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And I make a lot of typos.

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So I have pre-built most of this code.

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Knock on wood.

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And so yeah.

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If you go to this GitHub
repository, you're

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welcome to clone it, download
it, fork it, whatever you'd like.

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There's all sorts of stuff on there.

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The latest directory, I think, has
actually the thing that works the most.

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It's the one that's deployed.

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This is actually a live app on Heroku.

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I will mention a little
bit, there are some things

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that aren't related directly
to the topics of the seminar.

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We'll be talking a little bit
about Heroku just briefly.

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And we'll kind of briefly skim over
some Bootstrap and JavaScript and stuff

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like that.

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They're just not the
focuses of the seminar.

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So I probably won't explain
them very well or at all.

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I'll just kind of mentioned
that this is where those are.

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There's a lot of great documentation
for both Heroku and Bootstrap.

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JavaScript is questionable.

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And so if you're more
interested in that,

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you're welcome to go
and figure that one out.

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They're fully implemented
in the code base.

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So hopefully not too bad.

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Yeah, getting right into it.

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Basically, Python, beautiful basically
multipurpose language, super versatile.

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You can use it for machine learning.

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You can use it for computer vision,
data processing, web development,

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which is what we'll be doing here.

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Web development is a very vague term.

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It means roughly just building
things that go onto the internet.

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That's roughly the idea.

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I think people generally
assign a bunch of terms to it

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that sound really cool, like full
stack, back end, front end developer.

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We're not really going to be in
any one of those particular things.

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I guess this is probably close-ish
to a full stack, whatever that means.

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And so we will basically be building
an app entirely from scratch in Python.

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All of it is in Python minus
the front end stuff, which

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will be in HTML, JavaScript, and CSS.

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But the stuff in the back, the
things that make everything work

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are in Python.

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And Python is a really cool language.

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It does all sorts of cool things.

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And it does them pretty well.

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And what I mean by that
is it's pretty readable.

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I can look at some code and pretty
quickly understand what's going on.

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It's extremely modular.

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So there are these modules,
and you import them.

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And they each have their own
functionality and things that they do.

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I'm generally a fan of
clean and elegant code.

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Now, I say that.

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And then we're going to look at my code.

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And I'm sure there is someone out there
who will go, ah, that's not clean.

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It's not elegant.

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And I will agree.

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That's correct.

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It can always be improved.

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But generally speaking, I am always
looking towards that paradigm.

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And because of that, I particularly
like Django as a framework.

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Here at CS50, we actually
teach the framework

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of Flask, which is very similar.

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There are a lot of
similarities between the two.

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But it's a little bit, I
think, more small-scale.

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And then we kind of teach
like all three separately.

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The databases, the controlling
part of it, and then the front end

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are all kind of separated in CS50's
way of teaching it, where we teach

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Flask for the back end controller part.

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We teach Jinja2 as
our templating engine.

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So how do we control HTML?

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How do we generate that?

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And then we use, I believe,
MySQL for the back end.

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Django is kind of all three in one.

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It just brings them all together.

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Django has its own templating engine.

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It's very similar if you've been
following along with CS50 stuff.

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It's very similar to Jinja1.

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And then a lot of its paradigms for
how things are controlled in the back

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and used are also quite similar, though
a little bit more Pythonic, I think.

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That's a dangerous statement.

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We'll say that I just like
them a little bit more.

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That's more of a personal choice.

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And then I believe we're actually using
the same database back end as MySQL.

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We're using MySQL.

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However, it doesn't necessarily matter
you can actually swap back ends out

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underneath Django.

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And it's pretty quick, very convenient.

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And we'll see later that deploying
to Heroku, that is very convenient.

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Well, we might not see it a whole lot.

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But I'll point it out.

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So yeah, Django makes all of that
come into one framework, one package.

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And it's super convenient to use.

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We'll talk a little bit about
downloading the dependencies

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and things.

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But it's basically just Django.

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And then we'll talk a little bit about--

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I'm using Waitress as
the server for Django,

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because Django comes with some
built-in controllers for running

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a server locally and abroad, remotely.

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And that isn't super suitable to
even basic developmental purposes,

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except for local development.

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And since we put it on Heroku, I
figured it would be a decent time

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to throw out that Waitress is a really
great platform for actually running

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these sorts of things.

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But yeah, in Django, there are three
main ideas underneath this framework.

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And when people say framework,
they can mean all sorts of things.

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What I mean here is
that this is a platform

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on which you can build pretty quick,
very clean, very versatile web apps.

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And it's built entirely in Python.

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So I'm a huge fan.

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I'm kind of addicted to Python.

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And I've really learned
to love Django a lot.

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So in Django, these three
main ideas are actually

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shared across a lot of
the web development space,

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except it's called a little
bit different of a thing.

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So there's this acronym, MVC,
models, views, and controllers.

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That's kind of the general
web development term.

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Because of the way
that Django is set up,

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we actually call MVT, which is
models, views, and templates.

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And it ends up swapping
two of the terms roughly,

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as far as position goes,
but otherwise not too bad.

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So I'm going to talk about
it in the Django context,

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because I promise the seminar will
be mostly about Python and Django,

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with definitely an emphasis on Django.

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And so models are very cool.

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If you want to look at what they are
in Python, they are in this file,

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models.py.

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They are classes in Python.

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If you understand Python's
classes, if you understand

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classes and inheritance
and things like that,

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then you understand models in Django.

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And you might be like, whooptie-doo,
models, cool, don't really care.

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But models are our database.

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That is how we represent
data in our database.

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Each individual item, you could roughly
think of it as a table in a database.

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And so Django has this
high-level abstraction

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for how we represent
data in our database.

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And it does it in a way that
is extremely congruent with how

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Python represents classes.

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In fact, they are Python classes.

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And so that's super convenient
for the, I will say,

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intermediate or aspiring or
advanced Pythonic developer.

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And I'm a huge fan of just being
able to write classes for things

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and not really have to worry about
SQL, SQL syntax, or any of that.

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For example, I haven't had to
debug a SQL error message since--

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well, I guess since teaching CS50.

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And so I'm a huge fan of the way
models are written in Django.

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The only thing that I think is
particularly troublesome in Django,

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and we will talk about it, are
these things called migrations.

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So you build all these models.

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You write all these models down.

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They're beautiful.

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They're eloquent.

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They're perfectly well-written.

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And then you have to migrate
them onto your application.

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And what that means is that
you have to tell Django

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how these tables should be structured,
how things should actually be designed.

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And you actually make
these migrations first.

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They live in their own folder.

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And we'll talk about them a little bit.

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And then you have to
actually migrate them over.

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If you don't do that, nothing gets
actually changed in your data.

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It's a bunch of paper changes.

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And I think that that's one of
the troublesome parts of Django

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development.

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It's pretty well done, I think.

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I couldn't think of,
necessarily, something better

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off the top of my own head.

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But it's a little frustrating.

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I have lost lots of data
before because of that.

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And to be clear, that is not
the Django developer's fault.

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That it's certainly my own.

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And that's my own confusion
and then experience.

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So we'll try and clarify a
little bit of that as we go.

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Let's see, the next part
is views, the V of MVT.

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And so views are basically
Django's way of controlling

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what happens in the back.

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So you can think of it as, in web
development or in the web in general,

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there are users or clients.

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I might refer to it as browser-side,
client-side, user-side.

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Basically, I just mean the person
with the laptop accessing our website.

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Excuse me.

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Or the phone or however they're getting
to our website, they are the client.

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And that user is going to
send some sort of request,

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preferably through HTTP or
HTTPS, actually, would be ideal.

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And that request might be some
form of get request or post.

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And they'll send that
to me, the server-side.

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And I will generally try to refer to
myself as server-side, everything else

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as client-side, since I am developing.

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And on that side, on my
side, on the server-side,

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I'm going to try and
handle that request.

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I have to figure out
where it was intended for,

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what I should do when it gets there.

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Should I process certain data from it?

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Do I assume certain data exists from it?

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There's all sorts of
things to do with that.

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And that is Django's views.

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So there is a views.py
for every app in Django.

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You might be wondering what
the heck is an app in Django.

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And I will point that out shortly.

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Sorry, there's a little bit of
a chicken and egg problem here.

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But we'll get there in a sec.

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And views in Django basically
say, hey, what did you get.

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What kind of URL was parsed here?

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What kind of arguments are there?

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And then it handles them accordingly.

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And if that sounds vague, it's
because it's actually just very open.

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It's very versatile.

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It can be used for all sorts of things.

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One of the things that
is worth mentioning here

243
00:10:40,230 --> 00:10:43,200
is that Django's URL
system is really pretty.

244
00:10:43,200 --> 00:10:47,160
I like the fact that there are no
file extensions in their URL system,

245
00:10:47,160 --> 00:10:48,780
at least not built-in.

246
00:10:48,780 --> 00:10:55,830
Everything is just domain name slash
whatever without a .html, .php,

247
00:10:55,830 --> 00:10:56,850
or whatever it is.

248
00:10:56,850 --> 00:10:59,040
And I particularly enjoy that.

249
00:10:59,040 --> 00:11:02,610
It's also very easy to alias a
bunch of URLs to the same view.

250
00:11:02,610 --> 00:11:04,110
You can do all sorts of things.

251
00:11:04,110 --> 00:11:07,710
It's very, very well-designed, I think.

252
00:11:07,710 --> 00:11:09,095
So there are views for Django.

253
00:11:09,095 --> 00:11:11,970
We'll cover each of these things in
a little bit more concrete detail

254
00:11:11,970 --> 00:11:13,142
in a moment.

255
00:11:13,142 --> 00:11:16,350
And then there are templates, which is
basically the way that Django actually

256
00:11:16,350 --> 00:11:17,900
represents HTML.

257
00:11:17,900 --> 00:11:19,650
And the reason they're
called templates is

258
00:11:19,650 --> 00:11:24,510
because it's not written in
pure HTML on the server side.

259
00:11:24,510 --> 00:11:29,250
It is actually written in a mixture of
a HTML, JavaScript, CSS, the standards,

260
00:11:29,250 --> 00:11:31,830
and Django's templating engine.

261
00:11:31,830 --> 00:11:35,220
And so if you've ever used a templating
engine before, you've got it.

262
00:11:35,220 --> 00:11:36,600
But if you haven't, no worries.

263
00:11:36,600 --> 00:11:38,080
Templating engines are really cool.

264
00:11:38,080 --> 00:11:39,780
They give us a lot of power.

265
00:11:39,780 --> 00:11:43,860
We'll see it very early on that if we
were to write an index page or a home

266
00:11:43,860 --> 00:11:47,250
page, and if we were
to then write a other,

267
00:11:47,250 --> 00:11:50,160
maybe posts or articles page,
and then an authors page,

268
00:11:50,160 --> 00:11:53,460
and then in each of these things,
each one has like a nav bar--

269
00:11:53,460 --> 00:11:56,880
but then I went and
added a favorites page.

270
00:11:56,880 --> 00:11:59,010
And now I've got to go
change each nav bar.

271
00:11:59,010 --> 00:12:02,850
And I'm going to overexaggerate how
tedious that is when we get there.

272
00:12:02,850 --> 00:12:03,926
It's annoying.

273
00:12:03,926 --> 00:12:07,050
And not only is it annoying, but if
you're working on a team of developers,

274
00:12:07,050 --> 00:12:10,230
it can lead to a lot of inconsistencies.

275
00:12:10,230 --> 00:12:14,010
Simply put, it can lead to a
lot of inconsistencies in style.

276
00:12:14,010 --> 00:12:17,190
But even worse, it can lead to
inconsistencies in thought process

277
00:12:17,190 --> 00:12:18,780
and actual design choices.

278
00:12:18,780 --> 00:12:20,610
And that can be really bad.

279
00:12:20,610 --> 00:12:22,680
And I said really bad
as a vague, scary term.

280
00:12:22,680 --> 00:12:24,570
But it has a lot of implications.

281
00:12:24,570 --> 00:12:28,660
We might have a developer who forgets
to do a certain thing in the navigation

282
00:12:28,660 --> 00:12:29,160
bar.

283
00:12:29,160 --> 00:12:32,310
And then whenever you get to
customer support, you can't get back.

284
00:12:32,310 --> 00:12:33,510
Bummer.

285
00:12:33,510 --> 00:12:36,120
And those sorts of things
might not necessarily

286
00:12:36,120 --> 00:12:39,600
matter to you, the developer,
who knows your website very well.

287
00:12:39,600 --> 00:12:43,550
But to the average user trying to get
to your website for the first time,

288
00:12:43,550 --> 00:12:46,860
it can be really frustrating not
having an intuitive user interface.

289
00:12:46,860 --> 00:12:50,760
So following what does it mean
to be a real user of your website

290
00:12:50,760 --> 00:12:53,149
whenever you're web developing
is really important.

291
00:12:53,149 --> 00:12:55,440
What might be intuitive to
you because you've sat there

292
00:12:55,440 --> 00:12:58,454
for 35 hours straight
looking at this code

293
00:12:58,454 --> 00:13:00,870
might not be intuitive to the
person who has never visited

294
00:13:00,870 --> 00:13:02,700
your website before in their lives.

295
00:13:02,700 --> 00:13:07,770
So we'll stick to a very
basic standard of not

296
00:13:07,770 --> 00:13:10,590
quite the monolithic one-page website.

297
00:13:10,590 --> 00:13:14,760
I'm not a huge fan of those, although
they are nice, and they have purpose.

298
00:13:14,760 --> 00:13:20,130
But we are going to be on kind of the
thing in the front, nav bar at the top,

299
00:13:20,130 --> 00:13:22,620
navigate to any page in one click.

300
00:13:22,620 --> 00:13:26,610
And that is a kind of simplified version
of a web development practice, which

301
00:13:26,610 --> 00:13:29,940
is basically just to keep
everything as flat as possible,

302
00:13:29,940 --> 00:13:33,952
meaning that I don't have to click
very far to get into everything.

303
00:13:33,952 --> 00:13:35,910
So we've covered a little
bit about what Django

304
00:13:35,910 --> 00:13:39,111
is, a little bit about
the paradigm underneath.

305
00:13:39,111 --> 00:13:40,110
Let's look at some code.

306
00:13:40,110 --> 00:13:43,360
So if you have looked at
this GitHub repository,

307
00:13:43,360 --> 00:13:46,320
then you certainly know a little
bit about what's going on.

308
00:13:46,320 --> 00:13:47,490
I left some READMEs there.

309
00:13:47,490 --> 00:13:48,180
I apologize.

310
00:13:48,180 --> 00:13:51,690
My sense of humor from this talk
is actually bleeding through.

311
00:13:51,690 --> 00:13:55,140
You will get a sense of my sense
of humor, and it's terrible.

312
00:13:55,140 --> 00:13:58,320
If you're interested,
this is my command line.

313
00:13:58,320 --> 00:14:02,780
This is the repository that
you hopefully have access to.

314
00:14:02,780 --> 00:14:05,370
And what we're going to
look at is the actual code.

315
00:14:05,370 --> 00:14:10,350
So I labeled them in classic CS style
starting at 0 and going up to 7.

316
00:14:10,350 --> 00:14:12,160
So there are 8 stages total.

317
00:14:12,160 --> 00:14:16,440
And we're going to say a
goal is to get to stage 5.

318
00:14:16,440 --> 00:14:19,470
It's a decently complete
web application.

319
00:14:19,470 --> 00:14:22,320
We'll ideally get to stage 6.

320
00:14:22,320 --> 00:14:27,150
And if there's magic in the
world, we'll get to stage 7.

321
00:14:27,150 --> 00:14:29,399
So we're going to start at stage 0.

322
00:14:29,399 --> 00:14:31,440
And basically, we're going
to spend a lot of time

323
00:14:31,440 --> 00:14:33,210
looking at this file structure here.

324
00:14:33,210 --> 00:14:35,850
So I'll expand that
a little bit for you.

325
00:14:35,850 --> 00:14:38,410
And what you see here is
there's this pycache directory.

326
00:14:38,410 --> 00:14:39,456
It gets ignored by Git.

327
00:14:39,456 --> 00:14:40,830
We're not too worried about that.

328
00:14:40,830 --> 00:14:42,720
This dv.sqlite3.

329
00:14:42,720 --> 00:14:48,120
Sorry, we use SQLite as the
actual database structure.

330
00:14:48,120 --> 00:14:50,580
And then we have this
manage.py, readme.md,

331
00:14:50,580 --> 00:14:54,990
which is just explaining what's
going on, run.sh, and we have rango.

332
00:14:54,990 --> 00:14:56,599
And so actually, that's a great point.

333
00:14:56,599 --> 00:14:59,640
I'm going to tell you a little bit
about what we're actually doing today,

334
00:14:59,640 --> 00:15:04,710
since that is a reasonable question
that was probably asked a while ago.

335
00:15:04,710 --> 00:15:10,530
I thought it was really cute and
punny/funny to say randomized Django

336
00:15:10,530 --> 00:15:13,270
blog, rango.

337
00:15:13,270 --> 00:15:13,770
Yeah.

338
00:15:13,770 --> 00:15:16,780
So that was a lot funnier to me
at around 4:00 AM two days ago.

339
00:15:16,780 --> 00:15:18,570
But it's still kind of funny to me.

340
00:15:18,570 --> 00:15:20,040
And I hope you enjoy it.

341
00:15:20,040 --> 00:15:23,070
But the idea basically
being a lot of people

342
00:15:23,070 --> 00:15:27,780
build their first Django app
as some sort of basic blog.

343
00:15:27,780 --> 00:15:29,100
I'm kind of lazy.

344
00:15:29,100 --> 00:15:32,207
And I didn't really want to go
stealing through web scraping

345
00:15:32,207 --> 00:15:33,540
a bunch of other people's blogs.

346
00:15:33,540 --> 00:15:37,290
So I figured, why not create
some kind of randomized blog.

347
00:15:37,290 --> 00:15:38,730
It's not particularly pretty.

348
00:15:38,730 --> 00:15:42,220
But there are things you
could do to improve on it.

349
00:15:42,220 --> 00:15:45,000
But again, this is
definitely trying to just get

350
00:15:45,000 --> 00:15:48,510
through a very large number
of practices and ideas

351
00:15:48,510 --> 00:15:50,010
in a very quick period of time.

352
00:15:50,010 --> 00:15:54,540
So what basically happened
here is, instead of stage 00,

353
00:15:54,540 --> 00:15:59,760
you might do django-admin
startproject of rango.

354
00:15:59,760 --> 00:16:02,460
And what that would
actually end up doing--

355
00:16:02,460 --> 00:16:05,630
and that command looks like this.

356
00:16:05,630 --> 00:16:06,740
Whoops.

357
00:16:06,740 --> 00:16:08,620
See, this is the problem
with coding live.

358
00:16:08,620 --> 00:16:10,400
I can never spell.

359
00:16:10,400 --> 00:16:12,660
That implies that I could
spell normally, I can't.

360
00:16:12,660 --> 00:16:13,490
Cool.

361
00:16:13,490 --> 00:16:16,970
So this command over
here is what I might

362
00:16:16,970 --> 00:16:19,516
use to start a new project in Django.

363
00:16:19,516 --> 00:16:21,890
And you might have typed that
into your console and been,

364
00:16:21,890 --> 00:16:23,870
like, command not found, Django admin.

365
00:16:23,870 --> 00:16:25,070
Why did you lie to me, Nick?

366
00:16:25,070 --> 00:16:26,280
And I apologize.

367
00:16:26,280 --> 00:16:28,550
I was not lying to you directly.

368
00:16:28,550 --> 00:16:32,449
Basically, you actually
need to install Django first

369
00:16:32,449 --> 00:16:34,490
before you can actually
run that sort of command.

370
00:16:34,490 --> 00:16:38,720
And so it is a PIP package you
can do pip install of Django.

371
00:16:38,720 --> 00:16:41,630
I just did that, at least as far
as building this project goes.

372
00:16:41,630 --> 00:16:43,280
And that will get us going.

373
00:16:43,280 --> 00:16:45,170
You'll notice in the
left of my prompt, I

374
00:16:45,170 --> 00:16:48,560
have this little
parenthetical rango over here.

375
00:16:48,560 --> 00:16:52,280
You're going to hear me say rango
and Django and Python and oh, no

376
00:16:52,280 --> 00:16:53,710
frequently.

377
00:16:53,710 --> 00:16:57,350
But rango being the name of just a
virtual environment that I setup.

378
00:16:57,350 --> 00:16:59,630
And virtual environments
are in a great aspect

379
00:16:59,630 --> 00:17:04,819
of controlling which version of
packages you're using in Python.

380
00:17:04,819 --> 00:17:07,010
They basically just
say, hey, I only want

381
00:17:07,010 --> 00:17:12,619
to use this set of packages for
this Python thing that I'm doing.

382
00:17:12,619 --> 00:17:14,849
So let's keep them all
separate from each other.

383
00:17:14,849 --> 00:17:19,099
For example, if I'm using the
Harvard Crimson's version of Django,

384
00:17:19,099 --> 00:17:22,690
I will have to go back
a couple of decades.

385
00:17:22,690 --> 00:17:26,890
So we are basically
saying here that we just

386
00:17:26,890 --> 00:17:32,260
want to use this particular project's
versions of every Python package.

387
00:17:32,260 --> 00:17:35,230
It also means that I can
just have those dependencies.

388
00:17:35,230 --> 00:17:39,370
And I can install them in a
requirements.txt, for example.

389
00:17:39,370 --> 00:17:41,950
So if you go to that GitHub
repository, then you're

390
00:17:41,950 --> 00:17:46,270
actually able to just do a pip install
-r of all of these requirements.

391
00:17:46,270 --> 00:17:49,510
And that will set you up with all the
requirements you could possibly need--

392
00:17:49,510 --> 00:17:53,110
knock on wood-- for the latest
version of this, as well

393
00:17:53,110 --> 00:17:54,800
as all the intermediates.

394
00:17:54,800 --> 00:17:56,396
So you're welcome to go do that.

395
00:17:56,396 --> 00:17:58,270
You're welcome to install
them one at a time.

396
00:17:58,270 --> 00:17:59,200
I'm not your mother.

397
00:17:59,200 --> 00:18:02,620
You're welcome to do
whatever you'd like.

398
00:18:02,620 --> 00:18:04,930
Beyond that, once
you've gotten that done,

399
00:18:04,930 --> 00:18:06,680
you can run this Django admin command.

400
00:18:06,680 --> 00:18:09,790
And now I'm no longer lying to you.

401
00:18:09,790 --> 00:18:11,980
And it will actually do--

402
00:18:11,980 --> 00:18:17,020
well, hopefully, it will do
what I tell you it would do.

403
00:18:17,020 --> 00:18:19,900
So django-admin
startproject rango will get

404
00:18:19,900 --> 00:18:22,270
you going with a project called rango.

405
00:18:22,270 --> 00:18:26,200
Now, Django-- oh, there's going
to be some fun tongue twisters.

406
00:18:26,200 --> 00:18:29,530
Django tries to set everything up in
a beautiful directory-based structure

407
00:18:29,530 --> 00:18:33,070
for you, meaning that when I ran
this, I would actually have ended up

408
00:18:33,070 --> 00:18:35,290
with a directory called rango.

409
00:18:35,290 --> 00:18:39,370
Mine is called stage 0, because I built
them into several separate stages.

410
00:18:39,370 --> 00:18:44,150
But it would then have inside of it
another directory with the same name.

411
00:18:44,150 --> 00:18:46,030
Now, you might be wondering why do that.

412
00:18:46,030 --> 00:18:47,410
That sounds non-flat.

413
00:18:47,410 --> 00:18:50,230
It sounds very nested and
hierarchical and annoying.

414
00:18:50,230 --> 00:18:53,740
And you'd be almost right, except
that within a project, which

415
00:18:53,740 --> 00:18:58,060
is what this upper directory
will be, the directory underneath

416
00:18:58,060 --> 00:19:01,480
in rango itself is
actually the main or root

417
00:19:01,480 --> 00:19:03,790
app underneath our Django application.

418
00:19:03,790 --> 00:19:08,020
So within a Django project, you have
applications that are installed.

419
00:19:08,020 --> 00:19:10,780
The first one that is created is
actually one of the main ones.

420
00:19:10,780 --> 00:19:12,190
It is the main one.

421
00:19:12,190 --> 00:19:16,030
And it is generally where
requests are going to go first.

422
00:19:16,030 --> 00:19:20,000
Now, you can configure the
heck out of Django, no problem.

423
00:19:20,000 --> 00:19:24,040
So I'm going to say things in
kind of this probabilistic way.

424
00:19:24,040 --> 00:19:25,450
You can generally do this.

425
00:19:25,450 --> 00:19:26,680
You can usually do this.

426
00:19:26,680 --> 00:19:29,860
It will usually be related
to the default settings.

427
00:19:29,860 --> 00:19:33,860
But technically speaking, you could
manipulate it however you'd like.

428
00:19:33,860 --> 00:19:37,190
So in this initial installation,
there's very little that has to be done.

429
00:19:37,190 --> 00:19:38,860
I just got it running.

430
00:19:38,860 --> 00:19:41,180
That was all I wanted it to do.

431
00:19:41,180 --> 00:19:47,200
So what we're going to do
is, if we go into stage_00,

432
00:19:47,200 --> 00:19:49,900
I can actually run this
application totally reasonably

433
00:19:49,900 --> 00:19:52,880
from my local computer.

434
00:19:52,880 --> 00:19:57,520
So what I can do there is
I can do python manage.py--

435
00:19:57,520 --> 00:20:00,240
manage.py being the management
interface for Django.

436
00:20:00,240 --> 00:20:03,790
So if I want to run a server, if
I want to migrate my database,

437
00:20:03,790 --> 00:20:08,530
if I want to do all sorts of
other things, I can do managed.py.

438
00:20:08,530 --> 00:20:10,890
And then we're going to do
exactly that, runserver.

439
00:20:10,890 --> 00:20:15,400
0.0.0.0 is-- I always forget how
many zeros there are in that.

440
00:20:15,400 --> 00:20:19,630
There are four, 0.0.0.0 is just
kind of display on my computer

441
00:20:19,630 --> 00:20:21,730
and open the interface
out to the public.

442
00:20:21,730 --> 00:20:27,430
8.8.8.8 is a nifty general
port for development use.

443
00:20:27,430 --> 00:20:30,070
You'll notice that Django
initially will give you this,

444
00:20:30,070 --> 00:20:31,720
you have 15 unapplied migrations.

445
00:20:31,720 --> 00:20:33,790
Those are all the admin page migrations.

446
00:20:33,790 --> 00:20:35,920
Admin is an interface built into Django.

447
00:20:35,920 --> 00:20:37,044
It's kind of cool.

448
00:20:37,044 --> 00:20:38,960
There's all sorts of
things we can do with it.

449
00:20:38,960 --> 00:20:41,530
I'm not going to touch on too
many of them during this talk.

450
00:20:41,530 --> 00:20:43,120
But it is a very useful interface.

451
00:20:43,120 --> 00:20:44,320
And it's worth looking up.

452
00:20:44,320 --> 00:20:46,730
I just think it's relatively intuitive.

453
00:20:46,730 --> 00:20:53,980
And so it'll tell me that I have at
0.0.0.0, 8.8.8.8 this thing running.

454
00:20:53,980 --> 00:20:57,550
I'm actually going to just
go here in my web browser.

455
00:20:57,550 --> 00:21:00,640
I would say your web browser
of choice will suffice.

456
00:21:00,640 --> 00:21:04,360
People generally disagree with my
use of Safari as a web browser.

457
00:21:04,360 --> 00:21:05,710
But that's all right.

458
00:21:05,710 --> 00:21:09,910
So you'll see this cute little
page from Django itself.

459
00:21:09,910 --> 00:21:10,780
We've done nothing.

460
00:21:10,780 --> 00:21:14,740
I literally just did a django-admin
startproject, went into that directory,

461
00:21:14,740 --> 00:21:16,010
and ran the server.

462
00:21:16,010 --> 00:21:18,250
So we have very little
to do in this stage.

463
00:21:18,250 --> 00:21:20,080
And you get this, it worked.

464
00:21:20,080 --> 00:21:22,360
You're on the right path.

465
00:21:22,360 --> 00:21:25,240
As long as you are there,
congrats, you did it.

466
00:21:25,240 --> 00:21:27,790
So we are now running a web server.

467
00:21:27,790 --> 00:21:28,720
It's local.

468
00:21:28,720 --> 00:21:30,980
And I'm actually able to
visit it and see what's up.

469
00:21:30,980 --> 00:21:32,620
There's nothing
interesting really on here.

470
00:21:32,620 --> 00:21:34,150
There's a bunch of
documentation on the bottom.

471
00:21:34,150 --> 00:21:36,025
Their documentation is
beautiful, by the way.

472
00:21:36,025 --> 00:21:39,530
I would definitely recommend reading
it or reading through it a little bit.

473
00:21:39,530 --> 00:21:42,305
Don't read it like a book, because
that would be a little weird.

474
00:21:42,305 --> 00:21:43,430
Again, I'm not your mother.

475
00:21:43,430 --> 00:21:44,901
You do whatever you want.

476
00:21:44,901 --> 00:21:46,150
And so we kind of get to here.

477
00:21:46,150 --> 00:21:47,441
We see that things are working.

478
00:21:47,441 --> 00:21:48,370
We're glad.

479
00:21:48,370 --> 00:21:51,140
Everything's wired up a little
bit, or at least mostly, correctly.

480
00:21:51,140 --> 00:21:54,400
Now, Django will output all
of these things for you.

481
00:21:54,400 --> 00:21:56,894
You get to get a live
log of what's going on.

482
00:21:56,894 --> 00:21:59,060
And when you're developing
or when you're debugging,

483
00:21:59,060 --> 00:22:01,040
this is actually really useful.

484
00:22:01,040 --> 00:22:03,710
So development-wise, this is
a great way to run the app.

485
00:22:03,710 --> 00:22:06,040
Excuse me.

486
00:22:06,040 --> 00:22:07,540
Oh, think I got some dust in my eye.

487
00:22:07,540 --> 00:22:09,010
That's fun.

488
00:22:09,010 --> 00:22:11,710
And there we go, I think.

489
00:22:11,710 --> 00:22:12,670
This is really useful.

490
00:22:12,670 --> 00:22:14,800
You can print all sorts
of things to this console.

491
00:22:14,800 --> 00:22:16,787
You can actually use logging practices.

492
00:22:16,787 --> 00:22:19,120
Generally speaking, if you're
running some sort web app,

493
00:22:19,120 --> 00:22:20,560
please use a real logger.

494
00:22:20,560 --> 00:22:22,330
There's a great article
on Python logging

495
00:22:22,330 --> 00:22:24,160
mechanisms out there on the internet.

496
00:22:24,160 --> 00:22:27,730
It's like the first thing you get
when you do "Python how to logging"

497
00:22:27,730 --> 00:22:29,150
on Google.

498
00:22:29,150 --> 00:22:32,080
And so I would definitely recommend
reading through that as well.

499
00:22:32,080 --> 00:22:35,000
That is a fantastic practice for
just keeping everything consistent.

500
00:22:35,000 --> 00:22:37,750
Logs are built in a really good
way for just grepping through them

501
00:22:37,750 --> 00:22:39,335
and seeing what's going on.

502
00:22:39,335 --> 00:22:39,835
So cool.

503
00:22:39,835 --> 00:22:41,244
We've gotten through stage 0.

504
00:22:41,244 --> 00:22:43,160
We can pat ourselves on
the back a little bit.

505
00:22:43,160 --> 00:22:45,670
And now we're going to
Control-C out of that.

506
00:22:45,670 --> 00:22:48,640
And we're going to go figure
out what is in stage 1.

507
00:22:48,640 --> 00:22:50,550
And I say that as if I don't know.

508
00:22:50,550 --> 00:22:52,960
But unfortunately, I do.

509
00:22:52,960 --> 00:22:53,980
Cool.

510
00:22:53,980 --> 00:22:59,262
So if we go into stage 1, there's
now a new thing that exists.

511
00:22:59,262 --> 00:23:01,720
There's a new directory I'd
like to draw your attention to.

512
00:23:01,720 --> 00:23:02,920
It's called web.

513
00:23:02,920 --> 00:23:06,550
And this one looks very similar
to our base directory or our base

514
00:23:06,550 --> 00:23:08,290
application, rango.

515
00:23:08,290 --> 00:23:10,910
However, it has a few
other things in it.

516
00:23:10,910 --> 00:23:14,590
And so when you do install
another app in Django,

517
00:23:14,590 --> 00:23:17,890
which looks roughly like
django-admin startapp--

518
00:23:17,890 --> 00:23:19,960
and this is the command
that was run for that.

519
00:23:19,960 --> 00:23:21,920
I'll bring that up to the top.

520
00:23:21,920 --> 00:23:22,840
We ran this command.

521
00:23:22,840 --> 00:23:25,430
And we got this web subdirectory.

522
00:23:25,430 --> 00:23:28,570
And what that did for us is it gave
us an actual application that's

523
00:23:28,570 --> 00:23:31,960
going to kind of run underneath Django.

524
00:23:31,960 --> 00:23:36,790
And so it's a little bit strange, in
that it itself is not really running.

525
00:23:36,790 --> 00:23:38,540
We're still running our main project.

526
00:23:38,540 --> 00:23:40,290
We're still using the
management interface

527
00:23:40,290 --> 00:23:42,320
to run things, at least for now.

528
00:23:42,320 --> 00:23:46,810
But it is the thing that's
actually doing our web deployment.

529
00:23:46,810 --> 00:23:49,490
And so there are a lot of
different ways of doing this.

530
00:23:49,490 --> 00:23:53,680
You could run it as this monolithic,
everything's under the rango app.

531
00:23:53,680 --> 00:23:56,320
And you don't do anything else.

532
00:23:56,320 --> 00:23:58,330
But I'm generally not
a fan of doing that.

533
00:23:58,330 --> 00:24:00,610
I think separating things
out by functionality

534
00:24:00,610 --> 00:24:01,810
is a really good practice.

535
00:24:01,810 --> 00:24:03,890
It makes debugging a lot easier.

536
00:24:03,890 --> 00:24:06,520
It also makes development
with a team a lot better.

537
00:24:06,520 --> 00:24:09,020
And I say that, again,
generalist statements.

538
00:24:09,020 --> 00:24:12,070
But what I mean by that is, if
I'm on a team with three people,

539
00:24:12,070 --> 00:24:14,890
I want to work on the web app
version of what's going on.

540
00:24:14,890 --> 00:24:17,620
He wants to work on the API
version of what's going on.

541
00:24:17,620 --> 00:24:20,800
And she wants to work on making
sure all of our URLs are beautiful

542
00:24:20,800 --> 00:24:24,370
and settings are configured correctly
for production and development.

543
00:24:24,370 --> 00:24:28,840
Then we can all do that at the same
time using some sort of version control

544
00:24:28,840 --> 00:24:31,030
and not step on each other's toes.

545
00:24:31,030 --> 00:24:33,430
If we were all working
in a monolithic views.py,

546
00:24:33,430 --> 00:24:39,820
models.py, et cetera, then the
API guy, the web guy, and probably

547
00:24:39,820 --> 00:24:42,880
our product manager woman
are all going to conflict.

548
00:24:42,880 --> 00:24:44,350
And it's going to be a pain.

549
00:24:44,350 --> 00:24:46,030
We might all end up killing each other.

550
00:24:46,030 --> 00:24:50,530
So generally speaking, keeping things
separated out has an actual purpose.

551
00:24:50,530 --> 00:24:51,907
There is a reason for that.

552
00:24:51,907 --> 00:24:53,740
And I think even in
doing personal projects,

553
00:24:53,740 --> 00:24:56,800
it is a really good practice
to get into that habit.

554
00:24:56,800 --> 00:24:59,410
It helps to make you a little
bit more efficient too.

555
00:24:59,410 --> 00:25:02,350
Generally speaking, I would
argue that there are plenty

556
00:25:02,350 --> 00:25:05,540
of arguments for why it's a good idea.

557
00:25:05,540 --> 00:25:07,810
So now you'll notice,
or you might notice,

558
00:25:07,810 --> 00:25:10,690
I will point out to you that there
are these kind of new directories.

559
00:25:10,690 --> 00:25:13,300
There's this migrations
directory within our web app.

560
00:25:13,300 --> 00:25:16,720
You'll notice it does not
exist in rango, the base app.

561
00:25:16,720 --> 00:25:19,450
However, in rango, we do
have this static directory,

562
00:25:19,450 --> 00:25:23,405
which I believe it actually
does exist in stage 0's rango.

563
00:25:23,405 --> 00:25:24,280
Oh, no, just kidding.

564
00:25:24,280 --> 00:25:24,880
Cool.

565
00:25:24,880 --> 00:25:26,749
So that is also a new directory.

566
00:25:26,749 --> 00:25:28,540
We're going to talk
about that in a second.

567
00:25:28,540 --> 00:25:31,030
We've also changed some of
the settings in this one.

568
00:25:31,030 --> 00:25:36,400
And we've added a basic
URL and a basic view.

569
00:25:36,400 --> 00:25:38,230
And no models have been modified yet.

570
00:25:38,230 --> 00:25:40,670
So we're going to talk
about that in a second.

571
00:25:40,670 --> 00:25:42,190
Let's start with static.

572
00:25:42,190 --> 00:25:48,130
So Django has a built-in
system for static files.

573
00:25:48,130 --> 00:25:52,810
And static files can be notoriously
annoying and difficult to configure.

574
00:25:52,810 --> 00:25:55,060
I'll do my best to explain them here.

575
00:25:55,060 --> 00:25:58,570
But honestly, it's worth playing around
with it and really getting an intuition

576
00:25:58,570 --> 00:25:59,890
yourself.

577
00:25:59,890 --> 00:26:03,970
So static is what refers
to all sorts of JavaScript,

578
00:26:03,970 --> 00:26:08,980
fonts, images, CSS in a Django web app.

579
00:26:08,980 --> 00:26:11,830
And so generally speaking, you're
only going to have, really,

580
00:26:11,830 --> 00:26:14,260
three or four folders in static.

581
00:26:14,260 --> 00:26:17,200
I like to keep mine actually
separated out, in that I actually

582
00:26:17,200 --> 00:26:19,180
separate out by app.

583
00:26:19,180 --> 00:26:22,730
So I say, underneath static,
there's each app's name.

584
00:26:22,730 --> 00:26:25,930
And then under each app,
there is each of the things

585
00:26:25,930 --> 00:26:28,930
that you want to actually control
or have in the static directory.

586
00:26:28,930 --> 00:26:31,700
So admin has already
been collected into here.

587
00:26:31,700 --> 00:26:37,840
The Django web management interface
command is python3 manage.py.

588
00:26:37,840 --> 00:26:43,030
That'll be the management interface
that I refer to is python3 manage.py.

589
00:26:43,030 --> 00:26:46,270
And then we can say
something like collectstatic.

590
00:26:46,270 --> 00:26:48,610
And that will allow us
to actually take all

591
00:26:48,610 --> 00:26:50,590
of the static things
that exist somewhere

592
00:26:50,590 --> 00:26:53,320
and shove them to wherever
they actually belong.

593
00:26:53,320 --> 00:26:57,790
And the reason I say that and
such weird terms is that for now,

594
00:26:57,790 --> 00:27:01,340
that means just the things that
you wrote here, keep them here.

595
00:27:01,340 --> 00:27:04,905
However, when we actually switch to some
sort of real production environment,

596
00:27:04,905 --> 00:27:08,155
which I don't believe we'll have time
to get to, but it is worth looking into,

597
00:27:08,155 --> 00:27:10,700
and there's great
documentation on that as well,

598
00:27:10,700 --> 00:27:14,110
we might want to use some sort of
content delivery network, or CDN,

599
00:27:14,110 --> 00:27:18,550
to actually move everything
off of our personal server.

600
00:27:18,550 --> 00:27:22,060
Django itself and a lot of
the services underneath it

601
00:27:22,060 --> 00:27:25,940
are not super great for serving
all of these static assets,

602
00:27:25,940 --> 00:27:27,910
particularly like images.

603
00:27:27,910 --> 00:27:29,860
They're kind of big and a pain to load.

604
00:27:29,860 --> 00:27:32,410
And we're not optimized
for it, especially

605
00:27:32,410 --> 00:27:33,850
if we have a high traffic volume.

606
00:27:33,850 --> 00:27:38,410
So it makes a lot more sense
to maybe use like an AWS S3

607
00:27:38,410 --> 00:27:40,540
to just have all of your static there.

608
00:27:40,540 --> 00:27:42,760
And then this command actually
becomes really useful,

609
00:27:42,760 --> 00:27:45,010
because it means that all
the local stuff we have here,

610
00:27:45,010 --> 00:27:47,200
we don't actually put that
into our version control.

611
00:27:47,200 --> 00:27:51,400
We just push that onto some sort
of remote content delivery network.

612
00:27:51,400 --> 00:27:53,990
And then it gets served from there.

613
00:27:53,990 --> 00:27:55,780
And again, a very cool practice.

614
00:27:55,780 --> 00:27:57,494
It's something that is very useful.

615
00:27:57,494 --> 00:27:59,410
And then this command
becomes important to us.

616
00:27:59,410 --> 00:28:02,810
For now, it's actually not
too essential that we use it.

617
00:28:02,810 --> 00:28:05,360
But it is there and, I
think, worth mentioning.

618
00:28:05,360 --> 00:28:07,300
So yeah, we have this static.

619
00:28:07,300 --> 00:28:10,900
We will later add a web
folder underneath static.

620
00:28:10,900 --> 00:28:14,710
And then that will have its own
CSS, JavaScript, fonts, images.

621
00:28:14,710 --> 00:28:18,510
I'm generally a person who prefers
to do motivated development.

622
00:28:18,510 --> 00:28:21,990
So when I have a need for something, I
will then go look it up, figure it out,

623
00:28:21,990 --> 00:28:23,290
and build it.

624
00:28:23,290 --> 00:28:26,304
So I'm not going to put that in
here yet, because we don't need it.

625
00:28:26,304 --> 00:28:29,470
I think that it helps keep my code a
little bit leaner and a little bit more

626
00:28:29,470 --> 00:28:31,660
streamlined.

627
00:28:31,660 --> 00:28:34,960
But we have the admin
interface's static files in here.

628
00:28:34,960 --> 00:28:36,560
And that's good enough for us.

629
00:28:36,560 --> 00:28:37,570
So that's static.

630
00:28:37,570 --> 00:28:41,350
Now, I said we modified
settings a little bit.

631
00:28:41,350 --> 00:28:42,370
Thank you.

632
00:28:42,370 --> 00:28:45,070
The IDE I'm using, by the
way, is Visual Studio Code.

633
00:28:45,070 --> 00:28:45,872
Love it a lot.

634
00:28:45,872 --> 00:28:47,080
I would definitely recommend.

635
00:28:47,080 --> 00:28:50,260
I also like Atom quite a
bit, a personal preference.

636
00:28:50,260 --> 00:28:51,760
There's this cool security key.

637
00:28:51,760 --> 00:28:53,860
Mine is in my version control.

638
00:28:53,860 --> 00:28:56,980
If you would like to go hack
this web app on my Heroku here,

639
00:28:56,980 --> 00:28:58,630
you're welcome to.

640
00:28:58,630 --> 00:29:00,190
It won't particularly matter to me.

641
00:29:00,190 --> 00:29:05,230
But the allowed host is
what's interesting here.

642
00:29:05,230 --> 00:29:07,420
And so Django actually
requires that you tell it

643
00:29:07,420 --> 00:29:09,520
which host it's allowed to be run on.

644
00:29:09,520 --> 00:29:13,300
So 127.0.0.1 is my own local computer.

645
00:29:13,300 --> 00:29:17,770
Well, it's the IP address for local
host, which is resolved to 127.0.0.1.

646
00:29:17,770 --> 00:29:19,960
And those two things just
allow me to run this app

647
00:29:19,960 --> 00:29:25,150
on my own computer using either
the local host or 127.0.0.1 domains

648
00:29:25,150 --> 00:29:26,600
or IPs or addresses.

649
00:29:26,600 --> 00:29:30,470
Now, rangodjango.herokuapp.com is
where this is actually live right now.

650
00:29:30,470 --> 00:29:33,160
You're welcome to visit it with
your smartphone or your laptop

651
00:29:33,160 --> 00:29:37,210
or your other internet-enabled device.

652
00:29:37,210 --> 00:29:40,570
You can explore a little bit of what
the final product of this whole project

653
00:29:40,570 --> 00:29:41,442
looks like.

654
00:29:41,442 --> 00:29:44,150
I don't believe we'll end up
actually getting there in this talk.

655
00:29:44,150 --> 00:29:45,525
But there are a bunch of READMEs.

656
00:29:45,525 --> 00:29:47,330
And all the code is online.

657
00:29:47,330 --> 00:29:49,610
It's on that GitHub from the beginning.

658
00:29:49,610 --> 00:29:53,620
And so this allows me to tell
Django, only run on these domains.

659
00:29:53,620 --> 00:29:56,480
Any other domain, don't work.

660
00:29:56,480 --> 00:30:00,220
And that's just kind of a quirk
of Django, a perk, I would say.

661
00:30:00,220 --> 00:30:03,760
Now, I've added in two apps
from the original start.

662
00:30:03,760 --> 00:30:07,480
django_waitress allows us to
use that server process Waitress

663
00:30:07,480 --> 00:30:09,784
to actually run and serve Django.

664
00:30:09,784 --> 00:30:11,950
I'm not going to be talking
about that one too much.

665
00:30:11,950 --> 00:30:16,390
But we've also added in the
main a root project app rango.

666
00:30:16,390 --> 00:30:20,290
And that comes from just this
actual subdirectory rango.

667
00:30:20,290 --> 00:30:23,290
And it tells Django to check in rango--

668
00:30:23,290 --> 00:30:26,140
that's way funnier than I
thought it was going to be--

669
00:30:26,140 --> 00:30:29,410
for actual templates, static
assets, things like that.

670
00:30:29,410 --> 00:30:34,840
It tells it to allow looking
into that app for certain things.

671
00:30:34,840 --> 00:30:36,560
Web has not been installed yet.

672
00:30:36,560 --> 00:30:39,730
But we just haven't really
needed to install it yet.

673
00:30:39,730 --> 00:30:41,431
We will want to install it soon.

674
00:30:41,431 --> 00:30:42,805
I think that's in the next stage.

675
00:30:42,805 --> 00:30:44,846
And we'll want to make
sure we take care of that.

676
00:30:44,846 --> 00:30:46,740
Then the last thing at the bottom--

677
00:30:46,740 --> 00:30:53,050
there we are-- is--

678
00:30:53,050 --> 00:30:54,970
you'll see I left a
comment there that says,

679
00:30:54,970 --> 00:30:56,590
this is not suitable for production.

680
00:30:56,590 --> 00:30:58,120
Don't do this for production.

681
00:30:58,120 --> 00:31:00,110
I repeat, don't do this for production.

682
00:31:00,110 --> 00:31:02,260
This will not help you as
far as production goes.

683
00:31:02,260 --> 00:31:04,894
However, it is a very simple
way to do some development.

684
00:31:04,894 --> 00:31:07,810
And it's a little bit quicker than
the production mechanisms might be.

685
00:31:07,810 --> 00:31:12,550
So what this says is this is the
static route, static URL, static dirs,

686
00:31:12,550 --> 00:31:14,427
and project route.

687
00:31:14,427 --> 00:31:16,260
And the reason this is
configured the way it

688
00:31:16,260 --> 00:31:17,860
is, in kind of this generalist way--

689
00:31:17,860 --> 00:31:19,560
I didn't hard code anything--

690
00:31:19,560 --> 00:31:21,540
well, give or take--

691
00:31:21,540 --> 00:31:24,000
is because it gets pushed onto Heroku.

692
00:31:24,000 --> 00:31:26,350
And Heroku configures a
bunch of stuff for me.

693
00:31:26,350 --> 00:31:29,581
So I don't really want to
mess with what they're doing.

694
00:31:29,581 --> 00:31:31,830
So I just say, you know what,
wherever this file sits,

695
00:31:31,830 --> 00:31:33,300
that's our project route.

696
00:31:33,300 --> 00:31:35,760
And then I make everything off of that.

697
00:31:35,760 --> 00:31:41,200
Now, static URL just tells
Django how to find static assets.

698
00:31:41,200 --> 00:31:44,110
And so whenever a
request comes through, we

699
00:31:44,110 --> 00:31:46,710
are going to see how, in
urls.py, we actually configured

700
00:31:46,710 --> 00:31:50,400
the URLs a little bit to make it a
little bit easier for Django to go,

701
00:31:50,400 --> 00:31:54,390
ho, OK, this is a static asset,
go here, as opposed to this

702
00:31:54,390 --> 00:31:58,170
is just a general URL, go there.

703
00:31:58,170 --> 00:32:02,130
And then the static route
itself is where on our directory

704
00:32:02,130 --> 00:32:04,230
structure is this located.

705
00:32:04,230 --> 00:32:06,780
If you switch to a
production-style version,

706
00:32:06,780 --> 00:32:09,870
then these two things become
actually remotely located.

707
00:32:09,870 --> 00:32:11,340
And that's kind of cool.

708
00:32:11,340 --> 00:32:14,190
Static dirs, this also depends
on how you're serving things.

709
00:32:14,190 --> 00:32:19,050
Because I'm using kind of just this
generalist, Ubuntu-ish, Heroku style

710
00:32:19,050 --> 00:32:22,480
of serving everything, I don't
have to worry about this too much.

711
00:32:22,480 --> 00:32:25,492
But actually, this is a
list of these URLs paths.

712
00:32:25,492 --> 00:32:27,450
And you can actually list
out a couple of them.

713
00:32:27,450 --> 00:32:28,620
And it'll check all of them.

714
00:32:28,620 --> 00:32:30,070
It does check them in order.

715
00:32:30,070 --> 00:32:33,526
And so if you have assets that are
named the same thing under the same path

716
00:32:33,526 --> 00:32:36,150
but they're in different directories,
be aware that one of them

717
00:32:36,150 --> 00:32:37,800
might get tripped and not the other.

718
00:32:37,800 --> 00:32:38,840
And they'll be in order.

719
00:32:38,840 --> 00:32:42,190
So that is kind of something to
keep in mind when you're debugging.

720
00:32:42,190 --> 00:32:46,320
Now, moving onto our urls.py, I left
the comments up there at the top.

721
00:32:46,320 --> 00:32:49,130


722
00:32:49,130 --> 00:32:51,050
There are these URL patterns.

723
00:32:51,050 --> 00:32:53,690
So we import from web.

724
00:32:53,690 --> 00:32:57,500
So this basically says, take the
web application that we made,

725
00:32:57,500 --> 00:33:00,440
and then take its URLs
file, and import that.

726
00:33:00,440 --> 00:33:02,630
We alias it to web_urls.

727
00:33:02,630 --> 00:33:04,640
I think this is generally
a decent practice.

728
00:33:04,640 --> 00:33:06,997
But you're welcome to do
whatever you'd like for it.

729
00:33:06,997 --> 00:33:08,330
I think it's just very readable.

730
00:33:08,330 --> 00:33:09,900
And then we have urlpatterns.

731
00:33:09,900 --> 00:33:13,650
And this is kind of just my default
for the root of the urlpatterns

732
00:33:13,650 --> 00:33:15,920
is I tell it to include
all of our static assets,

733
00:33:15,920 --> 00:33:19,100
include admin, and include
them in this order.

734
00:33:19,100 --> 00:33:21,980
Now, Django does care a little
bit about your urlpatterns

735
00:33:21,980 --> 00:33:27,020
being roughly in order, well,
actually exactly in order.

736
00:33:27,020 --> 00:33:29,130
It'll search them in
order top to bottom.

737
00:33:29,130 --> 00:33:33,320
So if you have two conflicting paths,
only the top one will ever be gotten

738
00:33:33,320 --> 00:33:38,300
to, as in if I had admin/ and admin/,
and they went to two different places,

739
00:33:38,300 --> 00:33:40,590
well, we would only get to the top one.

740
00:33:40,590 --> 00:33:42,740
So then we have the static assets here.

741
00:33:42,740 --> 00:33:45,680
And then I just include all my
other urlpatterns down here.

742
00:33:45,680 --> 00:33:50,420
Now, I am generally a fan of using
just some sort of regular expression

743
00:33:50,420 --> 00:33:54,380
version of a path or generally
a path, either/or, to get us

744
00:33:54,380 --> 00:33:58,460
to certain applications underneath.

745
00:33:58,460 --> 00:34:02,960
I like to use this regular expression
path with an empty string to match all,

746
00:34:02,960 --> 00:34:07,280
so that any URL that is
typed in will get us to that.

747
00:34:07,280 --> 00:34:11,389
Now, include means, actually, this
isn't exactly where my URLs are.

748
00:34:11,389 --> 00:34:12,889
Go look at the web URLs.

749
00:34:12,889 --> 00:34:16,230
They're all configured particularly
for the web application.

750
00:34:16,230 --> 00:34:20,120
That'll tell you more about how
to match things and what to do.

751
00:34:20,120 --> 00:34:22,729
So this is pretty general.

752
00:34:22,729 --> 00:34:25,520
It's not going to tell us too much
about how what works underneath.

753
00:34:25,520 --> 00:34:29,029
But it allows us to separate
out, our web URLs live in web,

754
00:34:29,029 --> 00:34:34,100
our API URLs live in the API,
our email URLs live in email.

755
00:34:34,100 --> 00:34:37,580
And that way, we can separate out
functionality a little bit cleaner.

756
00:34:37,580 --> 00:34:40,310
This just tells us what
to do, where we go.

757
00:34:40,310 --> 00:34:43,130
You might include some
sort of directory here.

758
00:34:43,130 --> 00:34:45,380
I think for web, that should
actually be the default.

759
00:34:45,380 --> 00:34:48,920
But it is pretty
reasonable to include api/.

760
00:34:48,920 --> 00:34:52,219
And then anytime they go
to like api/ blahbity-blah,

761
00:34:52,219 --> 00:34:55,350
they actually get directed to a
different part of your application.

762
00:34:55,350 --> 00:34:56,230
Cool.

763
00:34:56,230 --> 00:34:57,960
So we now have that.

764
00:34:57,960 --> 00:35:00,070
urls.py has been examined.

765
00:35:00,070 --> 00:35:04,617
Now we go into web, which is going to
have all sorts of other things in it.

766
00:35:04,617 --> 00:35:06,700
It has these migrations
which we mentioned before.

767
00:35:06,700 --> 00:35:08,810
They're not going to be
super useful to us yet.

768
00:35:08,810 --> 00:35:10,570
But we'll get there.

769
00:35:10,570 --> 00:35:12,010
And then we have admin.py.

770
00:35:12,010 --> 00:35:13,900
Again, not going to
matter too much to us

771
00:35:13,900 --> 00:35:15,610
right now or probably throughout this.

772
00:35:15,610 --> 00:35:17,741
But it is a very useful
thing to understand.

773
00:35:17,741 --> 00:35:19,990
This allows you to take all
the models that you build,

774
00:35:19,990 --> 00:35:22,090
all of those beautiful
classes in Python,

775
00:35:22,090 --> 00:35:24,490
and put them onto an
admin interface that

776
00:35:24,490 --> 00:35:27,220
is usable by the general
user of your site

777
00:35:27,220 --> 00:35:29,990
who doesn't necessarily need to
understand a whole lot of Python.

778
00:35:29,990 --> 00:35:33,160
It also lets you create instances
of models and stuff like that.

779
00:35:33,160 --> 00:35:34,142
You have apps.py.

780
00:35:34,142 --> 00:35:36,600
We're not going to talk too
much about apps.py or tests.py,

781
00:35:36,600 --> 00:35:37,699
though they are useful.

782
00:35:37,699 --> 00:35:39,490
And then you have
models.py, which is where

783
00:35:39,490 --> 00:35:43,060
we're going to actually create all of
our database structures and interfaces

784
00:35:43,060 --> 00:35:44,020
there.

785
00:35:44,020 --> 00:35:45,610
We'll get there in a little while.

786
00:35:45,610 --> 00:35:50,257
We have urls.py, which is very generally
built. It does very little right now.

787
00:35:50,257 --> 00:35:52,840
But we are going to point out
that it imports all of the views

788
00:35:52,840 --> 00:35:54,610
from this application.

789
00:35:54,610 --> 00:35:57,430
And then it does that same kind
of catch-all pattern matching

790
00:35:57,430 --> 00:36:00,190
to just say, hey, anything
that comes through here,

791
00:36:00,190 --> 00:36:02,980
throw that to this, which is index.

792
00:36:02,980 --> 00:36:06,850
Now, index is something that I
assume I imported from web.views.

793
00:36:06,850 --> 00:36:09,730
If I was a better developer, I
probably would have explicitly stated

794
00:36:09,730 --> 00:36:11,860
that index was imported from web.views.

795
00:36:11,860 --> 00:36:13,440
I am, however, a lazy developer.

796
00:36:13,440 --> 00:36:15,190
This is not necessarily
the best practice.

797
00:36:15,190 --> 00:36:18,230
It's not clear to me immediately
where index came from.

798
00:36:18,230 --> 00:36:21,550
However, I think that
it's tolerable for now.

799
00:36:21,550 --> 00:36:23,480
If you wanted to be a
much better developer,

800
00:36:23,480 --> 00:36:26,800
you would be very clear as to where
exactly index came from, otherwise

801
00:36:26,800 --> 00:36:29,570
it seems kind of magical.

802
00:36:29,570 --> 00:36:32,680
And then, speaking of where index
came from, we'll look at views.

803
00:36:32,680 --> 00:36:37,330
And within views.py, we
actually have access to index.

804
00:36:37,330 --> 00:36:39,696
So if you're confused
about how views work,

805
00:36:39,696 --> 00:36:42,820
they're actually something very similar
to something you probably hopefully

806
00:36:42,820 --> 00:36:45,220
already understand, which
is Python functions.

807
00:36:45,220 --> 00:36:47,567
And all they take in,
at least by default--

808
00:36:47,567 --> 00:36:49,150
and they can be expanded quite a bit--

809
00:36:49,150 --> 00:36:53,180
is this request objects, so that's your
HTTP request, it's either get, post.

810
00:36:53,180 --> 00:36:57,070
Oh, there's a bunch of other ones
like put, patch, and a few other ones.

811
00:36:57,070 --> 00:36:59,200
We'll talk mostly about get and post.

812
00:36:59,200 --> 00:37:04,540
And then it returns this very basic HTTP
response which just takes in some HTML

813
00:37:04,540 --> 00:37:07,184
as a string and puts that
back out to the user.

814
00:37:07,184 --> 00:37:09,850
And this is independent of whether
it's a get, post, put, patch.

815
00:37:09,850 --> 00:37:11,080
It doesn't matter.

816
00:37:11,080 --> 00:37:14,550
It will do this every single
time it receives a request.

817
00:37:14,550 --> 00:37:19,000
And I imported HTTP response
from Django's HTTP submodule.

818
00:37:19,000 --> 00:37:21,520
That's generally, I think,
a decent way to start.

819
00:37:21,520 --> 00:37:24,220
It lets me just know that I
got things working correctly.

820
00:37:24,220 --> 00:37:27,110
And speaking of getting
things working correctly,

821
00:37:27,110 --> 00:37:30,790
let's go ahead and verify
that that's actually true.

822
00:37:30,790 --> 00:37:33,460
We'll run the same command
that we ran before.

823
00:37:33,460 --> 00:37:36,610
It's going to print out the same
error about unapplied migrations.

824
00:37:36,610 --> 00:37:37,152
It's correct.

825
00:37:37,152 --> 00:37:38,609
We have not applied our migrations.

826
00:37:38,609 --> 00:37:40,420
We don't really have
a whole lot to apply.

827
00:37:40,420 --> 00:37:44,350
And when I reload the page, I get to
Hello comma world, exclamation point.

828
00:37:44,350 --> 00:37:45,190
Hello, world!

829
00:37:45,190 --> 00:37:46,390
And so I have gotten here.

830
00:37:46,390 --> 00:37:47,560
It's very ugly.

831
00:37:47,560 --> 00:37:49,000
It's mostly white space.

832
00:37:49,000 --> 00:37:52,730
But we do have that in the
upper left-hand corner.

833
00:37:52,730 --> 00:37:54,790
And that should make
sense to us, because we

834
00:37:54,790 --> 00:37:58,330
created a view that controlled
any sort of response

835
00:37:58,330 --> 00:38:00,850
so that after I put in
the URL into my browser

836
00:38:00,850 --> 00:38:07,720
and it sends a request to our basic
127.0.0.1:8.8.8.8, then Django said,

837
00:38:07,720 --> 00:38:12,100
OK, well, we should go and match
that to whatever matches first here.

838
00:38:12,100 --> 00:38:13,840
It doesn't match admin at least.

839
00:38:13,840 --> 00:38:15,670
It doesn't match anything in static.

840
00:38:15,670 --> 00:38:18,450
But it does match the
everything wildcard.

841
00:38:18,450 --> 00:38:20,590
And that says, go into weburls.

842
00:38:20,590 --> 00:38:22,300
OK, so let's go to weburls.

843
00:38:22,300 --> 00:38:26,846
And that says, match anything, then take
that request, and hand it off to index.

844
00:38:26,846 --> 00:38:27,970
And that's in our views.py.

845
00:38:27,970 --> 00:38:28,840
So we look at index.

846
00:38:28,840 --> 00:38:30,820
And we say, OK, we take in some request.

847
00:38:30,820 --> 00:38:32,800
That was the HTTP request that we got.

848
00:38:32,800 --> 00:38:37,210
And regardless of what it was, just
return this open-handed hello world

849
00:38:37,210 --> 00:38:39,650
using the first type of header.

850
00:38:39,650 --> 00:38:40,949
That was a mouthful.

851
00:38:40,949 --> 00:38:41,990
And that's what happened.

852
00:38:41,990 --> 00:38:43,720
So I am very glad.

853
00:38:43,720 --> 00:38:46,220
I don't know if you're very
glad, but hopefully you are too.

854
00:38:46,220 --> 00:38:49,511
I'm particularly glad
that worked beautifully.

855
00:38:49,511 --> 00:38:54,390
And so yes, that actually is what
ended up going on underneath the hood.

856
00:38:54,390 --> 00:38:59,240
And we roughly understand a lot
about how Django works generally.

857
00:38:59,240 --> 00:39:02,330
Now, I say that the URLs can be
configured to be kind of magical.

858
00:39:02,330 --> 00:39:05,267
And we're going to see
that in a hot second.

859
00:39:05,267 --> 00:39:07,850
That is kind of a weird expression
in English, just as an FYI.

860
00:39:07,850 --> 00:39:11,980
So we're going to go up into stage 2.

861
00:39:11,980 --> 00:39:14,440
Cool, we have very
similar things in stage 2.

862
00:39:14,440 --> 00:39:15,700
We haven't modified much.

863
00:39:15,700 --> 00:39:18,079
I tried to make these
pretty reasonable stages

864
00:39:18,079 --> 00:39:20,120
but we're going to actually
write some HTML here.

865
00:39:20,120 --> 00:39:23,920
And so the way HTML and templating
in general works in Django

866
00:39:23,920 --> 00:39:26,560
is it uses Django's
built-in templating engine.

867
00:39:26,560 --> 00:39:29,020
You can actually modify
the engines underneath.

868
00:39:29,020 --> 00:39:31,210
Django's settings.py
is extremely versatile.

869
00:39:31,210 --> 00:39:34,030
It allows you to configure all
sorts of environment variables

870
00:39:34,030 --> 00:39:36,540
and just variables in general
for Django to be using.

871
00:39:36,540 --> 00:39:40,370
And anything in Django,
any subapp, any subfile

872
00:39:40,370 --> 00:39:42,370
can actually access all
of the settings configs.

873
00:39:42,370 --> 00:39:43,661
And we'll see that in a second.

874
00:39:43,661 --> 00:39:49,360
Actually, we saw that
in rango's urls.py.

875
00:39:49,360 --> 00:39:51,680
We import settings up here at the top.

876
00:39:51,680 --> 00:39:54,520
And you can access any of the
conflict variables in settings

877
00:39:54,520 --> 00:39:58,900
with settings.configvariablename,
just something useful to know.

878
00:39:58,900 --> 00:40:01,780
So we didn't really change
this urls.py very much.

879
00:40:01,780 --> 00:40:04,270
We don't need to in
order to add templating.

880
00:40:04,270 --> 00:40:06,190
Static has not really
changed a whole lot.

881
00:40:06,190 --> 00:40:09,250
Nothing in rango, the base
app, has really changed.

882
00:40:09,250 --> 00:40:12,430
However, in web, we have modified
a little bit of what's going on.

883
00:40:12,430 --> 00:40:14,320
Now, we have built some templates.

884
00:40:14,320 --> 00:40:15,970
In fact, we've built two.

885
00:40:15,970 --> 00:40:18,549
They're index.html and posts.html.

886
00:40:18,549 --> 00:40:21,340
We're building a randomized blog,
because I thought that was funny,

887
00:40:21,340 --> 00:40:22,720
and it made for a cool name.

888
00:40:22,720 --> 00:40:26,530
So it makes sense that we would have
some home page or index and some posts

889
00:40:26,530 --> 00:40:29,800
page that lets us deliver our posts.

890
00:40:29,800 --> 00:40:32,870
Now, I wanted to be a little bit
contrived in classic CS style.

891
00:40:32,870 --> 00:40:35,950
So this is kind of a derpy page.

892
00:40:35,950 --> 00:40:37,340
It's got very little in it.

893
00:40:37,340 --> 00:40:39,880
In its body, I've got container fluid.

894
00:40:39,880 --> 00:40:40,840
That's from Bootstrap.

895
00:40:40,840 --> 00:40:44,807
But I basically just display "Hello,
this is rango, the random Django blog."

896
00:40:44,807 --> 00:40:47,140
And then there's a bunch of
other stuff that's included.

897
00:40:47,140 --> 00:40:48,160
This is just--

898
00:40:48,160 --> 00:40:51,490
I basically just copied it
from Bootstrap's documentation.

899
00:40:51,490 --> 00:40:53,660
I like Bootstrap quite a bit.

900
00:40:53,660 --> 00:40:56,735
I think that generally, you should
build a web app from complete scratch

901
00:40:56,735 --> 00:40:59,110
before you actually start
using some of those frameworks.

902
00:40:59,110 --> 00:41:01,550
It helps give you a better
intuition for what's going on.

903
00:41:01,550 --> 00:41:03,070
But there's some other
tags up here that we're not

904
00:41:03,070 --> 00:41:04,480
going to worry too much about.

905
00:41:04,480 --> 00:41:08,800
And then I copied and pasted
which, according to see CS51 here,

906
00:41:08,800 --> 00:41:11,020
you should never ever do in code.

907
00:41:11,020 --> 00:41:14,500
I think it's like a
never, ever with a star.

908
00:41:14,500 --> 00:41:16,380
Generally, try not to.

909
00:41:16,380 --> 00:41:19,141
And as a good rule of thumb, if
you're copying and pasting code,

910
00:41:19,141 --> 00:41:21,640
you could probably abstract
something out or build something

911
00:41:21,640 --> 00:41:22,714
a little bit better.

912
00:41:22,714 --> 00:41:25,630
It's almost like I'm foreshadowing
what we're going to do in a second.

913
00:41:25,630 --> 00:41:28,570
But I copied and pasted this code.

914
00:41:28,570 --> 00:41:31,420
And so we have basically the
same page, except in its body,

915
00:41:31,420 --> 00:41:36,370
it displays whatever the content
of that page is, a rango post,

916
00:41:36,370 --> 00:41:38,620
because rango Django, random Django.

917
00:41:38,620 --> 00:41:41,290
But in here, we have a paragraph tag.

918
00:41:41,290 --> 00:41:44,980
And we have this curly brace
curly brace, variable name,

919
00:41:44,980 --> 00:41:46,320
curly brace curly brace.

920
00:41:46,320 --> 00:41:48,820
And I say variable name like
that because it's not intuitive

921
00:41:48,820 --> 00:41:50,500
that that is a variable name.

922
00:41:50,500 --> 00:41:52,700
But this is templating syntax.

923
00:41:52,700 --> 00:41:55,750
It's the first of a little
bit that we will see.

924
00:41:55,750 --> 00:41:57,370
It's the only one on this page.

925
00:41:57,370 --> 00:42:03,190
And what it says is that somewhere in
this nebulous Django templating engine,

926
00:42:03,190 --> 00:42:05,780
post_content has been defined.

927
00:42:05,780 --> 00:42:08,980
If it hasn't, Django just
goes, oops, and just runs it,

928
00:42:08,980 --> 00:42:12,310
because it's a little bit weird
to display some sort of error.

929
00:42:12,310 --> 00:42:15,310
Django actually does have
templating errors that can occur.

930
00:42:15,310 --> 00:42:16,570
And those are great.

931
00:42:16,570 --> 00:42:19,810
The more errors that you can catch
and the more modular and atomic they

932
00:42:19,810 --> 00:42:22,060
are, the better, because
then I can know, oh,

933
00:42:22,060 --> 00:42:24,040
exactly what I'm trying to fix.

934
00:42:24,040 --> 00:42:26,140
The generalist catch-all,
which we actually

935
00:42:26,140 --> 00:42:31,450
do do later in the views.py
where we do try except:,

936
00:42:31,450 --> 00:42:34,030
there's no exception in
particular that is caught.

937
00:42:34,030 --> 00:42:34,696
That's awful.

938
00:42:34,696 --> 00:42:36,820
How are you going to know
what exception was there?

939
00:42:36,820 --> 00:42:38,167
How do you know what went wrong?

940
00:42:38,167 --> 00:42:40,750
It's really good for making sure
that your application doesn't

941
00:42:40,750 --> 00:42:41,610
stumble and fall.

942
00:42:41,610 --> 00:42:43,780
It just kind of stumbles,
looks around, and hopes

943
00:42:43,780 --> 00:42:45,430
no one noticed and then keeps going.

944
00:42:45,430 --> 00:42:48,850
But generally, you want to
know, when you're developing,

945
00:42:48,850 --> 00:42:52,300
what exactly went wrong
as precisely as possible.

946
00:42:52,300 --> 00:42:54,310
So templating errors are really cool.

947
00:42:54,310 --> 00:42:56,530
And the reason that
those can occur in Django

948
00:42:56,530 --> 00:43:00,700
is because templates get rendered
before they ever get sent to the user.

949
00:43:00,700 --> 00:43:03,160
So this will never be
visible to the user.

950
00:43:03,160 --> 00:43:06,070
This will get replaced with
whatever it is as a variable.

951
00:43:06,070 --> 00:43:09,010
And you use this curly
brace-curly brace to indicate

952
00:43:09,010 --> 00:43:10,670
that I want this to be in there.

953
00:43:10,670 --> 00:43:13,210
It's generally used for
some sort of content.

954
00:43:13,210 --> 00:43:15,820
And so this should be
probably some sort of string,

955
00:43:15,820 --> 00:43:18,640
because it's going into
a P tag or paragraph tag.

956
00:43:18,640 --> 00:43:23,860
And so hopefully, knock on wood, the
developer who built this-- that's me--

957
00:43:23,860 --> 00:43:26,310
made sure that this was
some sort of string.

958
00:43:26,310 --> 00:43:29,560
And you might be wondering,
cool, cool, where?

959
00:43:29,560 --> 00:43:30,834
Where was this defined?

960
00:43:30,834 --> 00:43:32,000
And that's a great question.

961
00:43:32,000 --> 00:43:33,083
I'm really glad you asked.

962
00:43:33,083 --> 00:43:36,540
So if you go into your views.py,
we've modified that too.

963
00:43:36,540 --> 00:43:37,300
Go, us!

964
00:43:37,300 --> 00:43:39,760
And so we actually have this same index.

965
00:43:39,760 --> 00:43:42,100
But we have, also, posts.

966
00:43:42,100 --> 00:43:44,020
And you might be going,
you said the same.

967
00:43:44,020 --> 00:43:44,777
You lied.

968
00:43:44,777 --> 00:43:45,610
That's not the same.

969
00:43:45,610 --> 00:43:49,780
This is no longer an HTTP
response, at least not explicitly.

970
00:43:49,780 --> 00:43:51,740
It's a render.

971
00:43:51,740 --> 00:43:55,090
And then we have passed than and
the request itself as well as

972
00:43:55,090 --> 00:43:56,980
the name of one of our templates.

973
00:43:56,980 --> 00:44:00,900
Now, there's a lot that had to change
in Django to get this to happen.

974
00:44:00,900 --> 00:44:05,600
But let's say that we went and we
return render of request index.html.

975
00:44:05,600 --> 00:44:08,360
And then we do this weird
context as a dictionary.

976
00:44:08,360 --> 00:44:12,020
And then we say context
at post_content--

977
00:44:12,020 --> 00:44:13,610
hey, that looks familiar--

978
00:44:13,610 --> 00:44:17,137
is defined as this long
string of lorem ipsum.

979
00:44:17,137 --> 00:44:18,720
I pulled that from an API, by the way.

980
00:44:18,720 --> 00:44:19,700
I did not build it myself.

981
00:44:19,700 --> 00:44:21,056
I also did not manually type it.

982
00:44:21,056 --> 00:44:22,430
I can't type nearly that quickly.

983
00:44:22,430 --> 00:44:24,170
I'd still be typing it.

984
00:44:24,170 --> 00:44:27,050
And so then we have
return the rendering of--

985
00:44:27,050 --> 00:44:29,360
this is very similar up to this point--

986
00:44:29,360 --> 00:44:34,220
of the return above where we render--
this is the request that was passed in.

987
00:44:34,220 --> 00:44:37,501
It lets us set session IDs and variables
and caches and cookies and things.

988
00:44:37,501 --> 00:44:40,250
And then this is where we're
actually going, like what web page do

989
00:44:40,250 --> 00:44:41,800
we actually return to the user.

990
00:44:41,800 --> 00:44:47,910
And then this, context=context is a
very convenient way that Django passes,

991
00:44:47,910 --> 00:44:49,580
things into the templating engine.

992
00:44:49,580 --> 00:44:54,200
So I've defined, as one of the keys of
the context dictionary, post_content.

993
00:44:54,200 --> 00:44:56,420
And its value is this string.

994
00:44:56,420 --> 00:44:59,540
And you'll notice that we have
guaranteed, kind of by hard coding,

995
00:44:59,540 --> 00:45:02,070
that this will be a string.

996
00:45:02,070 --> 00:45:06,620
And so by doing that, we now have
access to this post_content variable

997
00:45:06,620 --> 00:45:08,510
within our Django templating engine.

998
00:45:08,510 --> 00:45:10,205
And hopefully we're very happy.

999
00:45:10,205 --> 00:45:12,080
However, if you were to
just do these things,

1000
00:45:12,080 --> 00:45:13,580
it still would not entirely work.

1001
00:45:13,580 --> 00:45:16,160
We have to make sure that Django
knows how to get to posts.

1002
00:45:16,160 --> 00:45:19,830
I still use this general catch-all
to get us to index, or our home page.

1003
00:45:19,830 --> 00:45:27,930
However, if you pass in posts now,
you actually go to the posts view.

1004
00:45:27,930 --> 00:45:29,390
I'm still using import*.

1005
00:45:29,390 --> 00:45:33,380
However, it would be equivalent
and probably better coding to do

1006
00:45:33,380 --> 00:45:35,780
posts,index.

1007
00:45:35,780 --> 00:45:37,010
That's not what I wanted.

1008
00:45:37,010 --> 00:45:38,050
Cool.

1009
00:45:38,050 --> 00:45:40,160
And then you might be going, excellent.

1010
00:45:40,160 --> 00:45:41,750
This will now work perfectly.

1011
00:45:41,750 --> 00:45:45,440
And you'd be almost correct, except
it won't, because templates is not

1012
00:45:45,440 --> 00:45:47,880
something we explicitly
tell Django to go look for,

1013
00:45:47,880 --> 00:45:50,870
at least a we might not have
noticed where we told it to do that.

1014
00:45:50,870 --> 00:45:54,110
We told it that in
settings.py in our root app.

1015
00:45:54,110 --> 00:45:56,930
But we actually never installed web.

1016
00:45:56,930 --> 00:45:59,960
So we're going to want to go up
into rango, under settings.py.

1017
00:45:59,960 --> 00:46:01,850
And we're going to look
into installed apps.

1018
00:46:01,850 --> 00:46:04,110
And you'll notice web is now there.

1019
00:46:04,110 --> 00:46:06,740
And the reason for
that is because Django

1020
00:46:06,740 --> 00:46:12,200
will check each of these things, each
of these apps for a templates directory.

1021
00:46:12,200 --> 00:46:15,440
And it'll say, hey, if you
have a templates directory,

1022
00:46:15,440 --> 00:46:17,330
kick those into the
things that we actually

1023
00:46:17,330 --> 00:46:19,240
check in order to render templates.

1024
00:46:19,240 --> 00:46:23,150
So when I say return render a
request and some template name,

1025
00:46:23,150 --> 00:46:26,180
it's going to look in these
ones' templates directories.

1026
00:46:26,180 --> 00:46:27,892
And then we'll go, oh, bummer.

1027
00:46:27,892 --> 00:46:29,600
And it's very common
for people to forget

1028
00:46:29,600 --> 00:46:32,510
to do this, yours truly
included, even now.

1029
00:46:32,510 --> 00:46:34,130
And then they go, why.

1030
00:46:34,130 --> 00:46:35,150
I made this template.

1031
00:46:35,150 --> 00:46:35,749
Where is it?

1032
00:46:35,749 --> 00:46:36,540
I don't understand.

1033
00:46:36,540 --> 00:46:38,336
Why is Django not working?

1034
00:46:38,336 --> 00:46:40,460
It's the equivalent of
yelling at the compiler when

1035
00:46:40,460 --> 00:46:42,890
you're doing C development.

1036
00:46:42,890 --> 00:46:45,020
It's not my fault. It's
your fault. And then you're

1037
00:46:45,020 --> 00:46:46,311
yelling at an inanimate object.

1038
00:46:46,311 --> 00:46:47,600
And people think you're weird.

1039
00:46:47,600 --> 00:46:48,930
Welcome to computer science.

1040
00:46:48,930 --> 00:46:52,181
So installing this saves you a
lot of trouble and frustration.

1041
00:46:52,181 --> 00:46:53,930
And it makes you look
a little less weird.

1042
00:46:53,930 --> 00:46:56,180
So just remember to do it.

1043
00:46:56,180 --> 00:47:00,110
And now everything is all
wired together correctly.

1044
00:47:00,110 --> 00:47:04,010
So we might go, OK, excellent manage.py.

1045
00:47:04,010 --> 00:47:06,509
And this command should
become second nature to you.

1046
00:47:06,509 --> 00:47:09,050
I'm actually going to stop
manually typing it out after this.

1047
00:47:09,050 --> 00:47:13,260
Oh, no, this is why you stop
manually typing that out.

1048
00:47:13,260 --> 00:47:14,234
There we go.

1049
00:47:14,234 --> 00:47:16,650
And you'll notice, if we open
up that output a little bit,

1050
00:47:16,650 --> 00:47:19,910
I still have 15 unapplied
migrations, unsurprising.

1051
00:47:19,910 --> 00:47:22,080
I kind of am deliberately ignoring that.

1052
00:47:22,080 --> 00:47:23,640
And we might re-render this.

1053
00:47:23,640 --> 00:47:27,400
It'll take a little bit longer, because
it's actually rendering something now.

1054
00:47:27,400 --> 00:47:30,626
And it's doing its job
a little bit better.

1055
00:47:30,626 --> 00:47:32,750
Yeah, the other thing
about live demos, anytime

1056
00:47:32,750 --> 00:47:35,150
you're doing real
coding or just anything

1057
00:47:35,150 --> 00:47:37,290
that depends on some
sort of time constraint

1058
00:47:37,290 --> 00:47:39,290
live, it's kind of like
when you need a printer.

1059
00:47:39,290 --> 00:47:40,940
It'll never work.

1060
00:47:40,940 --> 00:47:43,190
The internet stops
working just perpetually.

1061
00:47:43,190 --> 00:47:45,950
And this is a locally
hosted thing, and it still

1062
00:47:45,950 --> 00:47:47,690
stops working, which is ridiculous.

1063
00:47:47,690 --> 00:47:49,910
So you'll notice, in even
smaller text, because I

1064
00:47:49,910 --> 00:47:51,701
thought you guys needed
a little bit of eye

1065
00:47:51,701 --> 00:47:55,790
exercise, you'll see, "Hello, this
is rango, the random Django blog."

1066
00:47:55,790 --> 00:47:56,780
I think I'm funny.

1067
00:47:56,780 --> 00:48:01,010
And nothing else, so it's ugly as
heck would be a way to say that.

1068
00:48:01,010 --> 00:48:04,190
But if we going to posts, this
should change, fingers crossed.

1069
00:48:04,190 --> 00:48:07,400
And we get there, and this is a
rango post in much bigger text.

1070
00:48:07,400 --> 00:48:12,590
And then you get the cool lorem
ipsum blah, blah, blah there.

1071
00:48:12,590 --> 00:48:14,999
And that is exactly what
we hopefully expected,

1072
00:48:14,999 --> 00:48:17,540
because we didn't do any real
fancy formatting with Bootstrap

1073
00:48:17,540 --> 00:48:18,630
or anything of the sort.

1074
00:48:18,630 --> 00:48:21,020
So we get this.

1075
00:48:21,020 --> 00:48:26,510
And so we now have successfully looped
up some of what Django actually does,

1076
00:48:26,510 --> 00:48:29,780
which is fantastic for us.

1077
00:48:29,780 --> 00:48:33,590
Now that we've gotten through there,
we're going to go through stage 3.

1078
00:48:33,590 --> 00:48:36,932
And you'll notice, hopefully,
that as we kind of get going,

1079
00:48:36,932 --> 00:48:39,890
we'll get going a little bit faster
and faster, because things will not

1080
00:48:39,890 --> 00:48:40,635
really--

1081
00:48:40,635 --> 00:48:42,260
we won't have to change as many places.

1082
00:48:42,260 --> 00:48:44,059
And we'll just be changing a little bit.

1083
00:48:44,059 --> 00:48:46,850
Also, you guys will have a very
good intuition for what's going on.

1084
00:48:46,850 --> 00:48:49,391
Or y'all will have a very good
intuition for what's going on.

1085
00:48:49,391 --> 00:48:52,610
And we won't have to explain nearly
as much of what exactly is changing.

1086
00:48:52,610 --> 00:49:00,000
Now, in stage 3, we've said, OK, it was
really annoying to re-copy and paste.

1087
00:49:00,000 --> 00:49:02,867
I alluded to this at the very
beginning of the last stage.

1088
00:49:02,867 --> 00:49:04,950
I said, you know what, we
actually should probably

1089
00:49:04,950 --> 00:49:06,360
make this a little bit more extensible.

1090
00:49:06,360 --> 00:49:07,860
Our developers are all in a mess.

1091
00:49:07,860 --> 00:49:12,300
They all keep complaining that I change
code, and then Sally changes code,

1092
00:49:12,300 --> 00:49:15,510
and then Bob changes code, and no
one knows who changed what or when

1093
00:49:15,510 --> 00:49:16,260
or who's on first.

1094
00:49:16,260 --> 00:49:18,130
So it's really frustrating.

1095
00:49:18,130 --> 00:49:18,930
So we do this.

1096
00:49:18,930 --> 00:49:20,580
Now, there's all these curly braces.

1097
00:49:20,580 --> 00:49:22,704
And you're like, dude, you
just changed everything.

1098
00:49:22,704 --> 00:49:23,580
Nothing is the same.

1099
00:49:23,580 --> 00:49:24,810
What the heck?

1100
00:49:24,810 --> 00:49:26,250
And you'd be roughly right.

1101
00:49:26,250 --> 00:49:28,840
So what we've done is
actually quite a bit.

1102
00:49:28,840 --> 00:49:32,400
We've said, hey, there's this
curly brace percent sign,

1103
00:49:32,400 --> 00:49:34,260
not a double curly brace anymore.

1104
00:49:34,260 --> 00:49:38,040
And what that means is this is like
Django templating run a function.

1105
00:49:38,040 --> 00:49:39,660
So we run the extends function.

1106
00:49:39,660 --> 00:49:42,720
That can only be done once
at the top of the template.

1107
00:49:42,720 --> 00:49:44,400
You can only extend one other template.

1108
00:49:44,400 --> 00:49:46,660
But you can chain a bunch of extends.

1109
00:49:46,660 --> 00:49:48,840
And so we extend base.html.

1110
00:49:48,840 --> 00:49:51,060
And you're like, Nick, we
didn't write a base.html.

1111
00:49:51,060 --> 00:49:52,200
And I'm like, you're right.

1112
00:49:52,200 --> 00:49:53,820
We're going to go
point out what that is.

1113
00:49:53,820 --> 00:49:56,430
However, you might intuit that
that is going to just kind of,

1114
00:49:56,430 --> 00:49:59,310
do a general layout for what's going on.

1115
00:49:59,310 --> 00:50:00,690
Then we do this load static.

1116
00:50:00,690 --> 00:50:02,402
And you're like dude what the--

1117
00:50:02,402 --> 00:50:03,360
where'd that come from?

1118
00:50:03,360 --> 00:50:04,530
And I would agree.

1119
00:50:04,530 --> 00:50:05,610
It's a little confusing.

1120
00:50:05,610 --> 00:50:07,880
But this is alluding
to our static files.

1121
00:50:07,880 --> 00:50:14,040
It's generally a good thing to include
if you're going to use your own custom

1122
00:50:14,040 --> 00:50:15,820
static, which is what we did here.

1123
00:50:15,820 --> 00:50:17,040
Now, there's these blocks.

1124
00:50:17,040 --> 00:50:18,748
And we'll see what
those are in a second,

1125
00:50:18,748 --> 00:50:22,460
because they're actually defined
more similarly or more understandably

1126
00:50:22,460 --> 00:50:23,910
in base.html.

1127
00:50:23,910 --> 00:50:25,612
We have a block title.

1128
00:50:25,612 --> 00:50:27,820
Hopefully, intuitively,
that's the title of the page.

1129
00:50:27,820 --> 00:50:29,310
This is home, because it's index.

1130
00:50:29,310 --> 00:50:30,420
This is a block CSS.

1131
00:50:30,420 --> 00:50:33,390
It contains all of our custom
CSS that we don't necessarily

1132
00:50:33,390 --> 00:50:35,670
want to import to every
single page but we

1133
00:50:35,670 --> 00:50:37,540
want to import it whenever we need to.

1134
00:50:37,540 --> 00:50:39,520
So it gets included here.

1135
00:50:39,520 --> 00:50:41,910
And then this is just
our custom style sheet.

1136
00:50:41,910 --> 00:50:45,570
And since it's locally hosted,
it's defined by our own static.

1137
00:50:45,570 --> 00:50:49,350
We actually use this static tag
which will regenerate the URL based

1138
00:50:49,350 --> 00:50:51,240
on where our static
assets live, which makes

1139
00:50:51,240 --> 00:50:55,907
static assets being locally hosted
versus a CDN hosted very plug-and-play.

1140
00:50:55,907 --> 00:50:57,240
You just swap out the back ends.

1141
00:50:57,240 --> 00:51:00,210
And no one else notices.

1142
00:51:00,210 --> 00:51:03,010
And then we list out it's relative path.

1143
00:51:03,010 --> 00:51:06,040
And we have block body,
which is the body.

1144
00:51:06,040 --> 00:51:09,480
And it has all the same content as
before with a little bit more styling

1145
00:51:09,480 --> 00:51:11,390
due to bootstrap.

1146
00:51:11,390 --> 00:51:13,890
I don't like things looking too ugly.

1147
00:51:13,890 --> 00:51:18,092
And so I included some cuter
snippets here, whatever.

1148
00:51:18,092 --> 00:51:20,550
And then we look in posts, and
it's something very similar.

1149
00:51:20,550 --> 00:51:22,716
But you'll notice, it's a
lot less code them before.

1150
00:51:22,716 --> 00:51:25,830
We're at around 20 lines for
roughly the same content,

1151
00:51:25,830 --> 00:51:28,050
even though it'll look
a little bit prettier.

1152
00:51:28,050 --> 00:51:30,187
And so you'll see the post
content is still here.

1153
00:51:30,187 --> 00:51:31,770
This is under body, which makes sense.

1154
00:51:31,770 --> 00:51:34,722
We include the same style sheet.

1155
00:51:34,722 --> 00:51:36,180
And then we have a different title.

1156
00:51:36,180 --> 00:51:37,230
This is posts.

1157
00:51:37,230 --> 00:51:39,670
And we load static and extend base.html.

1158
00:51:39,670 --> 00:51:41,919
I don't know why I went
through that in reverse order.

1159
00:51:41,919 --> 00:51:44,940
If that was confusing, just watch
the YouTube video in reverse.

1160
00:51:44,940 --> 00:51:47,010
And then we're going
to go look up at rango.

1161
00:51:47,010 --> 00:51:50,877
And notice, it also has a
templates directory now.

1162
00:51:50,877 --> 00:51:52,710
And when we go into
that, there's base.html.

1163
00:51:52,710 --> 00:51:54,960
And you're like, oh, thank
god, that's where it went.

1164
00:51:54,960 --> 00:51:59,850
And this has all of our standard
doctype, html, charset, all this.

1165
00:51:59,850 --> 00:52:02,530
And then you'll notice
these empty blocks.

1166
00:52:02,530 --> 00:52:04,540
This is a CSS block
that has nothing in it.

1167
00:52:04,540 --> 00:52:06,150
And then you'll go, oh, of course.

1168
00:52:06,150 --> 00:52:08,560
When we did our index.html
and our post.html,

1169
00:52:08,560 --> 00:52:12,100
we wrapped it in the same block CSS
and block, but we put stuff in there.

1170
00:52:12,100 --> 00:52:13,530
We put stuff in the middle here.

1171
00:52:13,530 --> 00:52:17,190
And that actually just
gets copy-pasted onto this.

1172
00:52:17,190 --> 00:52:18,090
Same thing for title.

1173
00:52:18,090 --> 00:52:22,210
It does the exact same functionality,
except this is in the title tag.

1174
00:52:22,210 --> 00:52:23,400
And then I added a nav bar.

1175
00:52:23,400 --> 00:52:25,127
Don't worry too much about what that is.

1176
00:52:25,127 --> 00:52:26,710
I just copy and pasted from Bootstrap.

1177
00:52:26,710 --> 00:52:27,390
Bootstrap's great.

1178
00:52:27,390 --> 00:52:29,098
They do all sorts of
cool coding for you.

1179
00:52:29,098 --> 00:52:30,810
Just copy and paste it in.

1180
00:52:30,810 --> 00:52:32,970
And then I added the block body here.

1181
00:52:32,970 --> 00:52:34,540
And we added this JavaScript block.

1182
00:52:34,540 --> 00:52:35,373
We don't use it yet.

1183
00:52:35,373 --> 00:52:38,340
But it's a decent practice for not
including all of your JavaScript

1184
00:52:38,340 --> 00:52:40,230
all the time at every page.

1185
00:52:40,230 --> 00:52:41,700
It can be very heavy to include.

1186
00:52:41,700 --> 00:52:44,400
And by heavy, I mean it
takes a while over a network.

1187
00:52:44,400 --> 00:52:47,640
So again, I'm going to stop
typing that out by hand.

1188
00:52:47,640 --> 00:52:49,230
We're going to again run run server.

1189
00:52:49,230 --> 00:52:51,124
We again, have unapplied migrations.

1190
00:52:51,124 --> 00:52:52,790
None of that should be counterintuitive.

1191
00:52:52,790 --> 00:52:54,480
What you'll note is that it
looks a little bit prettier now.

1192
00:52:54,480 --> 00:52:55,620
We're still on posts.

1193
00:52:55,620 --> 00:52:57,900
We have a nav bar, which is great.

1194
00:52:57,900 --> 00:53:00,360
Rango, Random Django, Rango.

1195
00:53:00,360 --> 00:53:02,610
And then we have a jumbotron going on.

1196
00:53:02,610 --> 00:53:03,870
That's a bootstrap thing.

1197
00:53:03,870 --> 00:53:05,670
And we have cooler formatting.

1198
00:53:05,670 --> 00:53:08,232
It looks a little bit
prettier, give or take.

1199
00:53:08,232 --> 00:53:08,940
It was a low bar.

1200
00:53:08,940 --> 00:53:10,410
It was very easy to
make it look prettier.

1201
00:53:10,410 --> 00:53:11,993
And we can now switch between the two.

1202
00:53:11,993 --> 00:53:14,970
However, this is not a great blog,
in that we only have one post.

1203
00:53:14,970 --> 00:53:16,890
It's a hardcoded post.

1204
00:53:16,890 --> 00:53:19,770
And that's kind of derpy, not
that this whole thing isn't derpy.

1205
00:53:19,770 --> 00:53:21,839
But it's a little derpier than usual.

1206
00:53:21,839 --> 00:53:23,130
So we're going to go back here.

1207
00:53:23,130 --> 00:53:27,430
And sorry if I speed up a little, but I
don't want to run out of too much time.

1208
00:53:27,430 --> 00:53:29,280
And we'll go to stage 4.

1209
00:53:29,280 --> 00:53:33,757
And we'll say, OK, so we've gotten some
things working a little bit better.

1210
00:53:33,757 --> 00:53:35,340
Also, I didn't explain this very well.

1211
00:53:35,340 --> 00:53:37,250
And I will stop and
explain it for a second.

1212
00:53:37,250 --> 00:53:40,110
The reason I put this
base.html in the root project

1213
00:53:40,110 --> 00:53:45,630
is, generally speaking, my whole web app
should be pretty consistent, I think.

1214
00:53:45,630 --> 00:53:50,612
And so I want to put this base.html
in the thing that governs everything.

1215
00:53:50,612 --> 00:53:53,070
I think that that makes a lot
of sense if you're inheriting

1216
00:53:53,070 --> 00:53:55,350
something that is standard across.

1217
00:53:55,350 --> 00:53:58,140
No matter what kind of other
applications we have running here,

1218
00:53:58,140 --> 00:53:59,430
they should all look the same.

1219
00:53:59,430 --> 00:54:01,090
It should be very user-consistent.

1220
00:54:01,090 --> 00:54:05,010
I don't want my user to be jarred
by like banana slug orange.

1221
00:54:05,010 --> 00:54:06,000
Yellow?

1222
00:54:06,000 --> 00:54:08,700
And so that's why I
actually rationalized

1223
00:54:08,700 --> 00:54:10,890
putting this template set here.

1224
00:54:10,890 --> 00:54:14,490
In CS50, we use layout.html
instead of base.html.

1225
00:54:14,490 --> 00:54:16,530
I just think base is more
intuitive for myself.

1226
00:54:16,530 --> 00:54:19,321
And I think in general, it doesn't
change much about the semantics.

1227
00:54:19,321 --> 00:54:21,390
So that is what's going on there.

1228
00:54:21,390 --> 00:54:23,510
We are now in stage 4.

1229
00:54:23,510 --> 00:54:26,679
And what's going on
here is very similar.

1230
00:54:26,679 --> 00:54:29,970
We're actually now changing a little bit
about what's going on in the back end.

1231
00:54:29,970 --> 00:54:32,897
So we go into views.py.

1232
00:54:32,897 --> 00:54:34,230
And we haven't changed too much.

1233
00:54:34,230 --> 00:54:37,320
But I've been putting this requests
library, which, for some reason,

1234
00:54:37,320 --> 00:54:39,570
I thought was included
by default in Python.

1235
00:54:39,570 --> 00:54:43,990
I'd just deluded myself by having
it installed on my base computer.

1236
00:54:43,990 --> 00:54:48,410
So if we go into here, we'll see
posts has changed a little bit.

1237
00:54:48,410 --> 00:54:50,199
And so I use this list
comprehension here.

1238
00:54:50,199 --> 00:54:52,740
If it doesn't make any sense,
I'll explain it really briefly.

1239
00:54:52,740 --> 00:54:55,150
But what is worth shouting
out is lorem ipsum--

1240
00:54:55,150 --> 00:54:59,089
or loripsum-- hmm, never
really read that. loripsum.net,

1241
00:54:59,089 --> 00:55:00,380
they built all their own stuff.

1242
00:55:00,380 --> 00:55:01,296
Theirs is really cool.

1243
00:55:01,296 --> 00:55:02,490
I take no credit for that.

1244
00:55:02,490 --> 00:55:07,710
I'm just using their API to get a bunch
of blog posts for our random Django

1245
00:55:07,710 --> 00:55:10,060
application.

1246
00:55:10,060 --> 00:55:12,520
And then you'll notice that
my context is now a list.

1247
00:55:12,520 --> 00:55:15,311
So we're going to go look at how
that changed our templating engine

1248
00:55:15,311 --> 00:55:18,240
syntax, which is now a list
of each of those posts.

1249
00:55:18,240 --> 00:55:19,887
I do like this element.strip.

1250
00:55:19,887 --> 00:55:21,720
That just takes off new
lines and whitespace

1251
00:55:21,720 --> 00:55:23,130
on either side of the string.

1252
00:55:23,130 --> 00:55:26,310
It assumes that it's a
string for element in.

1253
00:55:26,310 --> 00:55:29,550
This is the response that we
got from our beautiful API.

1254
00:55:29,550 --> 00:55:31,440
The text version of
that response, I happen

1255
00:55:31,440 --> 00:55:34,790
to know it delivers text, the
plain text part of their API.

1256
00:55:34,790 --> 00:55:36,197
And then I split it by lines.

1257
00:55:36,197 --> 00:55:39,030
And I stripped off all the whitespace
on either side of those lines.

1258
00:55:39,030 --> 00:55:41,520
And as long as there is an
actual element there-- so in case

1259
00:55:41,520 --> 00:55:43,311
they had a double new
line somewhere, which

1260
00:55:43,311 --> 00:55:45,600
would end up being its own
element in this list, that

1261
00:55:45,600 --> 00:55:48,480
just gets ignored, because it gets
counted in Python as not existing

1262
00:55:48,480 --> 00:55:50,200
or IF fails.

1263
00:55:50,200 --> 00:55:52,230
So this is just kind of
a really convenient way.

1264
00:55:52,230 --> 00:55:54,920
It's pretty readable, I think,
once you get used to it,

1265
00:55:54,920 --> 00:55:57,584
for just going through and
doing that very quickly.

1266
00:55:57,584 --> 00:55:59,250
And then we do the same thing as before.

1267
00:55:59,250 --> 00:56:00,300
We deliver this request.

1268
00:56:00,300 --> 00:56:03,060
We have our posts.html
and then our context.

1269
00:56:03,060 --> 00:56:06,422
And that all should hopefully
make sense to everyone.

1270
00:56:06,422 --> 00:56:09,130
So then we're going to go look at
how that changed our templates.

1271
00:56:09,130 --> 00:56:11,896
So if we go into templates,
posts, most things

1272
00:56:11,896 --> 00:56:13,270
haven't really changed that much.

1273
00:56:13,270 --> 00:56:14,490
We've added JavaScript.

1274
00:56:14,490 --> 00:56:17,739
And we're not going to talk about that
too much, because this is about Django.

1275
00:56:17,739 --> 00:56:19,980
But I thought it was
kind of cute and quirky.

1276
00:56:19,980 --> 00:56:21,340
I'm a huge fan of randomness.

1277
00:56:21,340 --> 00:56:23,980
So then this has
changed, though, for us.

1278
00:56:23,980 --> 00:56:28,830
So what's going on here is, it's roughly
like writing Python, just in HTML.

1279
00:56:28,830 --> 00:56:32,100
And the reason I say roughly like
that is because we're not actually

1280
00:56:32,100 --> 00:56:33,870
writing Python in HTML.

1281
00:56:33,870 --> 00:56:37,500
There's no running of some sort
of Python code in the browser.

1282
00:56:37,500 --> 00:56:42,090
But on our side, on the server side,
we do actually execute some code

1283
00:56:42,090 --> 00:56:43,680
and generate some HTML.

1284
00:56:43,680 --> 00:56:46,080
And this might not
seem too big of a deal

1285
00:56:46,080 --> 00:56:48,466
to those of us who grew
up in this generation.

1286
00:56:48,466 --> 00:56:50,340
However, as someone who
used to not know what

1287
00:56:50,340 --> 00:56:53,940
this was, what templating engines were
and wrote out all of his own HTML,

1288
00:56:53,940 --> 00:56:54,790
it sucked.

1289
00:56:54,790 --> 00:56:55,630
It was awful.

1290
00:56:55,630 --> 00:56:57,900
So writing this is much more eloquent.

1291
00:56:57,900 --> 00:57:00,240
I can do things very extensively.

1292
00:57:00,240 --> 00:57:02,940
And it's a much more
dynamic way of writing code.

1293
00:57:02,940 --> 00:57:06,240
So we do four posts in posts.

1294
00:57:06,240 --> 00:57:09,840
Now, you'll notice posts is the new
variable that I actually send in.

1295
00:57:09,840 --> 00:57:12,510
It's defined as a key in
our context dictionary.

1296
00:57:12,510 --> 00:57:15,570
And when I go through posts,
it's going to just take

1297
00:57:15,570 --> 00:57:19,950
each item in that list, which is the
value of posts in our dictionary.

1298
00:57:19,950 --> 00:57:23,490
And it will give me access
to that variable here.

1299
00:57:23,490 --> 00:57:28,500
And so I now can run and do all
sorts of actual dynamic generation

1300
00:57:28,500 --> 00:57:29,492
of a bunch of posts.

1301
00:57:29,492 --> 00:57:30,950
I can change how many get rendered.

1302
00:57:30,950 --> 00:57:32,910
That's totally reasonable for us.

1303
00:57:32,910 --> 00:57:35,040
This is Rango Post #.

1304
00:57:35,040 --> 00:57:37,080
And then I do the forloop.counter.

1305
00:57:37,080 --> 00:57:39,960
I believe it's counter 0 if you
want a zero-indexed counter.

1306
00:57:39,960 --> 00:57:42,810
Otherwise, for loops in Django's
templating engine syntax

1307
00:57:42,810 --> 00:57:45,420
actually are one-indexed.

1308
00:57:45,420 --> 00:57:48,030
I don't know the reason
for that, but I don't mind.

1309
00:57:48,030 --> 00:57:49,610
Again, more unapplied migrations.

1310
00:57:49,610 --> 00:57:50,777
We're ignoring that for now.

1311
00:57:50,777 --> 00:57:52,609
We'll get to it, I
think, in the next stage.

1312
00:57:52,609 --> 00:57:54,330
But hey, we now have a bunch of posts.

1313
00:57:54,330 --> 00:57:56,970
And you know when I said that
the JavaScript was kind of cute,

1314
00:57:56,970 --> 00:57:58,490
it changes the--

1315
00:57:58,490 --> 00:58:00,330
eh, yeah, they're different colors.

1316
00:58:00,330 --> 00:58:02,220
But you'll notice we have all 10 posts.

1317
00:58:02,220 --> 00:58:02,940
And that's great.

1318
00:58:02,940 --> 00:58:03,990
That's what we would expect to see.

1319
00:58:03,990 --> 00:58:06,150
If we reload the page,
they'll all be different.

1320
00:58:06,150 --> 00:58:08,130
And that's because the API
just generates them randomly.

1321
00:58:08,130 --> 00:58:08,850
So that's very cool.

1322
00:58:08,850 --> 00:58:09,558
It's very random.

1323
00:58:09,558 --> 00:58:11,130
It's very Django rango.

1324
00:58:11,130 --> 00:58:12,150
And if we go to Home.

1325
00:58:12,150 --> 00:58:12,870
That should still work.

1326
00:58:12,870 --> 00:58:14,400
It hasn't really changed a whole lot.

1327
00:58:14,400 --> 00:58:15,750
I think I might have changed
some words or something.

1328
00:58:15,750 --> 00:58:16,710
Who knows?

1329
00:58:16,710 --> 00:58:19,680
But the main focus being here
that we now have a list of posts.

1330
00:58:19,680 --> 00:58:21,292
They're all separated out.

1331
00:58:21,292 --> 00:58:22,500
You might think this is ugly.

1332
00:58:22,500 --> 00:58:23,430
I might agree.

1333
00:58:23,430 --> 00:58:25,290
We can all just move on.

1334
00:58:25,290 --> 00:58:32,280
And so we can now go on
to stage 5, which is here.

1335
00:58:32,280 --> 00:58:33,430
There we go.

1336
00:58:33,430 --> 00:58:36,369
And when we go on to stage
5, we might be saying, OK,

1337
00:58:36,369 --> 00:58:37,410
what else is there to do.

1338
00:58:37,410 --> 00:58:39,210
You've really taken
this contrived concept.

1339
00:58:39,210 --> 00:58:40,501
You've beat it into the ground.

1340
00:58:40,501 --> 00:58:42,515
You've drilled it into our heads.

1341
00:58:42,515 --> 00:58:44,390
And we're going to do
that a little bit more.

1342
00:58:44,390 --> 00:58:48,850
So now, when we go into web,
same directory structure.

1343
00:58:48,850 --> 00:58:51,040
You should be like, yes,
we are familiar with this.

1344
00:58:51,040 --> 00:58:52,160
Don't say it again.

1345
00:58:52,160 --> 00:58:53,860
And I'll be like, yes, you're right.

1346
00:58:53,860 --> 00:58:58,087
We've added another one so that we can
actually modify what's going on here.

1347
00:58:58,087 --> 00:58:59,670
Now, this looks quite a bit different.

1348
00:58:59,670 --> 00:59:01,930
But you'll notice it's
actually not too bad.

1349
00:59:01,930 --> 00:59:03,260
It's the same thing here.

1350
00:59:03,260 --> 00:59:04,640
This is what we've seen before.

1351
00:59:04,640 --> 00:59:06,181
But I've added another version of it.

1352
00:59:06,181 --> 00:59:07,150
There's also this one.

1353
00:59:07,150 --> 00:59:10,150
It uses another API, very
well written, not mine.

1354
00:59:10,150 --> 00:59:12,550
I did not build any of that API.

1355
00:59:12,550 --> 00:59:15,040
That was built by Samir Kumar.

1356
00:59:15,040 --> 00:59:17,650
And that's all I have on that one.

1357
00:59:17,650 --> 00:59:18,970
But it's a really good thing.

1358
00:59:18,970 --> 00:59:20,886
And it has a bunch of
geeky jokes that I think

1359
00:59:20,886 --> 00:59:22,750
are really funny,
because, you know, geeky.

1360
00:59:22,750 --> 00:59:26,854
And so that one just takes the first 10.

1361
00:59:26,854 --> 00:59:29,020
This underscore just means
don't actually assign it.

1362
00:59:29,020 --> 00:59:30,220
Don't do a variable for it.

1363
00:59:30,220 --> 00:59:31,630
Just count through 10.

1364
00:59:31,630 --> 00:59:36,140
Range is what you use in Python to
iterate through a range of numbers.

1365
00:59:36,140 --> 00:59:40,650
And so then this says, if post_type
equals equals geeky, which is a string.

1366
00:59:40,650 --> 00:59:42,550
And you're like, where is post_type?

1367
00:59:42,550 --> 00:59:44,091
Where do you keep getting these from?

1368
00:59:44,091 --> 00:59:45,681
And I'm like, yeah, you're right.

1369
00:59:45,681 --> 00:59:47,680
And so you'll notice, I
actually defined context

1370
00:59:47,680 --> 00:59:51,460
up here so that I can append
to it down here if I need to.

1371
00:59:51,460 --> 00:59:53,600
And then I have post_type.

1372
00:59:53,600 --> 00:59:56,990
And you're like, wait, didn't you say
that this only takes in a request,

1373
00:59:56,990 --> 00:59:58,676
returns HTTP response?

1374
00:59:58,676 --> 00:59:59,800
And I will say, yes, I did.

1375
00:59:59,800 --> 01:00:01,966
I'm retracting that, kind
of like your chem teachers

1376
01:00:01,966 --> 01:00:03,970
did once you got to college.

1377
01:00:03,970 --> 01:00:05,410
Things have been changed here.

1378
01:00:05,410 --> 01:00:06,940
And I'm going to explain why.

1379
01:00:06,940 --> 01:00:09,940
So if you'll recall, I
said that URLs in Django

1380
01:00:09,940 --> 01:00:12,760
can actually be used to do all
sorts of really cool things.

1381
01:00:12,760 --> 01:00:15,280
In fact, you can use
them to pass parameters

1382
01:00:15,280 --> 01:00:17,780
to the function that
deals with it, the view.

1383
01:00:17,780 --> 01:00:20,440
And so that's what we've done
here is I defined some string.

1384
01:00:20,440 --> 01:00:23,110
And I matched it with
post_type equals equals geeky.

1385
01:00:23,110 --> 01:00:25,630
And then I do something
different based on that.

1386
01:00:25,630 --> 01:00:28,980
Otherwise, just go back to our
default, which is lorem ipsum.

1387
01:00:28,980 --> 01:00:32,987
And so you look in urls.py, things
have been modified a little bit.

1388
01:00:32,987 --> 01:00:34,570
So we've done a couple of things here.

1389
01:00:34,570 --> 01:00:38,980
But we're going to focus on this
first path thing, which is posts/.

1390
01:00:38,980 --> 01:00:42,054
And this takes in these like
less than, greater than signs.

1391
01:00:42,054 --> 01:00:43,720
I don't know the general term for these.

1392
01:00:43,720 --> 01:00:46,330
And it causes me a lot
of angst when I'm trying

1393
01:00:46,330 --> 01:00:50,080
to explain stuff to people,
because I'm like, this, this thing.

1394
01:00:50,080 --> 01:00:52,657
And I use less than, greater than.

1395
01:00:52,657 --> 01:00:54,490
If someone knows that,
someone will tell me,

1396
01:00:54,490 --> 01:00:56,560
I'm sure, in the left while doing so.

1397
01:00:56,560 --> 01:00:59,430
So what this says is,
if you go to posts/,

1398
01:00:59,430 --> 01:01:03,640
and whatever you put here is going to be
called post_type and sent as a variable

1399
01:01:03,640 --> 01:01:06,077
or passed as a parameter
to our view posts.

1400
01:01:06,077 --> 01:01:09,160
And that's what we've done is we've
said, hey, whatever gets passed there,

1401
01:01:09,160 --> 01:01:11,440
match that with either
geeky or anything.

1402
01:01:11,440 --> 01:01:13,534
And then do different
things accordingly.

1403
01:01:13,534 --> 01:01:14,950
And that's really important to us.

1404
01:01:14,950 --> 01:01:16,840
Now, you'll also notice,
hey, where'd this come from.

1405
01:01:16,840 --> 01:01:18,890
This is random and
doesn't make any sense.

1406
01:01:18,890 --> 01:01:21,040
I added a different view,
because I am sneaky.

1407
01:01:21,040 --> 01:01:24,347
And I said, hey, actually anytime
you add a favorite, pass in the quote

1408
01:01:24,347 --> 01:01:25,180
that you want to do.

1409
01:01:25,180 --> 01:01:26,800
And you're like, what is this.

1410
01:01:26,800 --> 01:01:27,880
This is so random.

1411
01:01:27,880 --> 01:01:31,300
And I will say, random, Django, rango.

1412
01:01:31,300 --> 01:01:33,220
And so yes, what
actually is going on here

1413
01:01:33,220 --> 01:01:35,800
is we are also adding in
the functionality of being

1414
01:01:35,800 --> 01:01:37,992
able to select certain
posts as our favorites

1415
01:01:37,992 --> 01:01:39,700
and have them get
stored to the database.

1416
01:01:39,700 --> 01:01:41,110
And you're like, database?

1417
01:01:41,110 --> 01:01:42,760
And I'm like, database.

1418
01:01:42,760 --> 01:01:44,720
And we're going to build a model.

1419
01:01:44,720 --> 01:01:48,280
And so when we get to models.py,
this is what's going on.

1420
01:01:48,280 --> 01:01:51,790
I built a class, because, hey,
models are just Python classes.

1421
01:01:51,790 --> 01:01:54,150
favorite(models.Model).

1422
01:01:54,150 --> 01:01:57,040
Yeah, models gets imported
by default. So that's cool.

1423
01:01:57,040 --> 01:02:00,011
And this just extends the
model base class from Django.

1424
01:02:00,011 --> 01:02:03,010
And then we say body, which is actually
going to be a field in the model

1425
01:02:03,010 --> 01:02:07,000
or an aspect of our class or, if you're
really thinking ahead, you're like,

1426
01:02:07,000 --> 01:02:11,590
wait a second, that's a column
in our table called favorite.

1427
01:02:11,590 --> 01:02:12,610
And you're right.

1428
01:02:12,610 --> 01:02:17,380
And so they follow the same general
practices as Python classes do.

1429
01:02:17,380 --> 01:02:18,850
You generally will capitalize them.

1430
01:02:18,850 --> 01:02:22,990
They will be not camel case but just
uppercase every word, no spaces,

1431
01:02:22,990 --> 01:02:23,980
certainly no spaces.

1432
01:02:23,980 --> 01:02:24,970
That's absurd.

1433
01:02:24,970 --> 01:02:27,130
But no underscores either.

1434
01:02:27,130 --> 01:02:28,750
Generally, you'll see this.

1435
01:02:28,750 --> 01:02:31,510
I only have one field here,
because again, contrived

1436
01:02:31,510 --> 01:02:33,370
random Django example, rango.

1437
01:02:33,370 --> 01:02:35,110
And we do models.TextField.

1438
01:02:35,110 --> 01:02:39,311
There's a great reference
on Django's documentation

1439
01:02:39,311 --> 01:02:41,310
that explains all of these
different fields, all

1440
01:02:41,310 --> 01:02:42,560
of their different parameters.

1441
01:02:42,560 --> 01:02:43,600
And they take a million.

1442
01:02:43,600 --> 01:02:46,300
And then I also define this
underscore underscore string.

1443
01:02:46,300 --> 01:02:48,910
It's a cool attribute
to define for classes.

1444
01:02:48,910 --> 01:02:51,640
It overrides the default
and says, actually, just

1445
01:02:51,640 --> 01:02:55,690
return favorite quotes
number of this item's ID.

1446
01:02:55,690 --> 01:03:01,450
That way, it doesn't do the weird
this of objects, favorite object,

1447
01:03:01,450 --> 01:03:02,632
or whatever it is.

1448
01:03:02,632 --> 01:03:05,090
So that's actually a really
convenient way of doing things.

1449
01:03:05,090 --> 01:03:09,250
And I would definitely recommend
it as a generalist practice.

1450
01:03:09,250 --> 01:03:10,600
So cool.

1451
01:03:10,600 --> 01:03:12,790
That also, I realize,
might not make any sense,

1452
01:03:12,790 --> 01:03:15,414
because it's on the admin interface,
which I didn't talk about.

1453
01:03:15,414 --> 01:03:18,600
And so if you were really curious
about where this comes into play,

1454
01:03:18,600 --> 01:03:20,308
go ahead and explore
the admin interface.

1455
01:03:20,308 --> 01:03:22,390
And that's really cool.

1456
01:03:22,390 --> 01:03:23,620
So we've created a model.

1457
01:03:23,620 --> 01:03:27,966
And then you're like, wait, but you also
called this addfavorite thing in views.

1458
01:03:27,966 --> 01:03:29,590
And I deliberately didn't show us that.

1459
01:03:29,590 --> 01:03:30,050
And you're right.

1460
01:03:30,050 --> 01:03:30,700
It's here.

1461
01:03:30,700 --> 01:03:33,790
In fact, we do this really bad
exception practicing where we say,

1462
01:03:33,790 --> 01:03:38,770
hey, any exception that ever
occurs, just return false, yay.

1463
01:03:38,770 --> 01:03:40,735
And so we're returning
JSON responses now.

1464
01:03:40,735 --> 01:03:42,250
And you're like, well, that's new.

1465
01:03:42,250 --> 01:03:44,090
And I'm like, yeah, you're right.

1466
01:03:44,090 --> 01:03:46,110
And so what basically
is happening here--

1467
01:03:46,110 --> 01:03:48,750
I'll try and get that
all on this screen--

1468
01:03:48,750 --> 01:03:51,800
is, if for our method is get, if
the request that's given to us

1469
01:03:51,800 --> 01:03:53,780
is actually a get
request, then we're going

1470
01:03:53,780 --> 01:03:57,590
to create a new favorite object,
set its body equivalent to whatever

1471
01:03:57,590 --> 01:04:00,800
the quote was, and remember,
that's the pattern or the thing

1472
01:04:00,800 --> 01:04:02,060
that we passed in here.

1473
01:04:02,060 --> 01:04:05,810
That's the variable from
our actual URL, Django URLs.

1474
01:04:05,810 --> 01:04:08,960
And then we're going to
save it to our database

1475
01:04:08,960 --> 01:04:13,730
and then return back to whoever sent
this request as a response, a JSON

1476
01:04:13,730 --> 01:04:17,270
response, which is
imported up here, and have

1477
01:04:17,270 --> 01:04:22,040
that be just the dictionary mapping
the key data to the value true,

1478
01:04:22,040 --> 01:04:23,180
because all of it worked.

1479
01:04:23,180 --> 01:04:24,306
Everything was good.

1480
01:04:24,306 --> 01:04:26,930
Otherwise, anytime an error
occurred or things were unexpected,

1481
01:04:26,930 --> 01:04:28,200
just return false.

1482
01:04:28,200 --> 01:04:30,560
Now, I think you can hopefully
see how this could maybe

1483
01:04:30,560 --> 01:04:32,450
be built a little bit more eloquently.

1484
01:04:32,450 --> 01:04:34,200
And I will agree with you there.

1485
01:04:34,200 --> 01:04:35,340
I pointed it out.

1486
01:04:35,340 --> 01:04:38,900
And so we'll talk about
that in a second maybe.

1487
01:04:38,900 --> 01:04:42,110
But if we go into
posts.html, you'll notice

1488
01:04:42,110 --> 01:04:45,530
we included a second
JavaScript, favorites.js.

1489
01:04:45,530 --> 01:04:52,220
We're writing all of those into
our rango, static, web, js, boom.

1490
01:04:52,220 --> 01:04:56,339
And once we get there, we might
say something like, OK, cool.

1491
01:04:56,339 --> 01:04:57,380
It does a bunch of stuff.

1492
01:04:57,380 --> 01:04:59,170
It does some Ajax requesting.

1493
01:04:59,170 --> 01:05:00,710
And we'll briefly cover that.

1494
01:05:00,710 --> 01:05:01,522
It looks like this.

1495
01:05:01,522 --> 01:05:04,730
We're not really going to discuss what
exactly is going on here, because it's

1496
01:05:04,730 --> 01:05:06,650
not relevant to Django explicitly.

1497
01:05:06,650 --> 01:05:09,020
But it is worth going
through and understanding.

1498
01:05:09,020 --> 01:05:12,800
And it uses our add_favorite url,
which is really the point of this.

1499
01:05:12,800 --> 01:05:14,717
And then it appends text to it.

1500
01:05:14,717 --> 01:05:16,550
That's the quote that
we wanted to favorite.

1501
01:05:16,550 --> 01:05:21,020
So now, if we do this
whole run server shebang,

1502
01:05:21,020 --> 01:05:25,160
this one will actually tell us that
we have no unapplied migrations.

1503
01:05:25,160 --> 01:05:27,200
I don't think that's true.

1504
01:05:27,200 --> 01:05:31,430
So we're going to talk about what
it means to apply a migration,

1505
01:05:31,430 --> 01:05:33,072
to make a migration, to migrate.

1506
01:05:33,072 --> 01:05:34,280
We don't mean like the birds.

1507
01:05:34,280 --> 01:05:36,880
We mean like Django.

1508
01:05:36,880 --> 01:05:39,594
Got to love all the weird animal
references in coding for Python,

1509
01:05:39,594 --> 01:05:42,260
because it's like a snake, but
it's also a programming language.

1510
01:05:42,260 --> 01:05:43,250
I think that's funny.

1511
01:05:43,250 --> 01:05:44,140
Ignore my jokes.

1512
01:05:44,140 --> 01:05:48,530
Manage.py, management interface,
we're going to make migrations.

1513
01:05:48,530 --> 01:05:50,040
And no changes were detected.

1514
01:05:50,040 --> 01:05:52,790
So I must have done this by
accident when I was tired.

1515
01:05:52,790 --> 01:05:53,597
But that's OK.

1516
01:05:53,597 --> 01:05:55,430
That is going to be the
first step that says

1517
01:05:55,430 --> 01:05:59,240
take all of the database changes of the
changes to models.py, and update them.

1518
01:05:59,240 --> 01:06:00,890
And then we're going to migrate across.

1519
01:06:00,890 --> 01:06:04,820
And so you'll notice it applies across
admin, off content type, sessions.

1520
01:06:04,820 --> 01:06:06,020
Those are all built-ins.

1521
01:06:06,020 --> 01:06:08,150
And web, which is good,
because we included that.

1522
01:06:08,150 --> 01:06:11,210
You can also migrate particular apps
by passing them in as a parameter.

1523
01:06:11,210 --> 01:06:13,682
Just apply web migrations.

1524
01:06:13,682 --> 01:06:15,140
Things like that are really useful.

1525
01:06:15,140 --> 01:06:18,720
You can also roll back migrations, roll
forward migrations, things like that.

1526
01:06:18,720 --> 01:06:22,160
And so we might then
say, OK, cool, cool.

1527
01:06:22,160 --> 01:06:24,140
I was doing a reverse
search, by the way.

1528
01:06:24,140 --> 01:06:26,470
And that was entirely useless.

1529
01:06:26,470 --> 01:06:27,830
We can just go up, boom.

1530
01:06:27,830 --> 01:06:30,300
Running the server,
nothing else to check.

1531
01:06:30,300 --> 01:06:31,550
We just get a bunch of output.

1532
01:06:31,550 --> 01:06:34,550
And we're going to go, OK, this
will hopefully do something.

1533
01:06:34,550 --> 01:06:35,700
Cool, we got Rango.

1534
01:06:35,700 --> 01:06:38,514
And so you'll notice,
actually, in our nav bar--

1535
01:06:38,514 --> 01:06:39,430
it looks really small.

1536
01:06:39,430 --> 01:06:41,020
I'm sorry if I'm straining your eyes.

1537
01:06:41,020 --> 01:06:43,220
We have both lorem
ipsum and geeky quotes.

1538
01:06:43,220 --> 01:06:46,400
Lorem ipsum has not changed.

1539
01:06:46,400 --> 01:06:48,059
This is ugly, and it's off to the side.

1540
01:06:48,059 --> 01:06:49,850
I don't think I corrected
it in this stage.

1541
01:06:49,850 --> 01:06:51,680
It's corrected in the next stage.

1542
01:06:51,680 --> 01:06:53,330
I generally prefer to center stuff.

1543
01:06:53,330 --> 01:06:54,840
And we have quote one.

1544
01:06:54,840 --> 01:06:55,790
I can click favorite.

1545
01:06:55,790 --> 01:06:58,380
And it'll say, hey, quote one
was favorited successfully.

1546
01:06:58,380 --> 01:06:59,732
And I'm like, woo!

1547
01:06:59,732 --> 01:07:01,190
And then we can go to geeky quotes.

1548
01:07:01,190 --> 01:07:06,260
And we can say, oh, Chuck Norris
can touch MC Hammer, funny.

1549
01:07:06,260 --> 01:07:09,980
And so these are just kind of a funny
set of jokes that are kind of cute.

1550
01:07:09,980 --> 01:07:12,170
Again, pulled from an
API that I did not write.

1551
01:07:12,170 --> 01:07:15,050
And we might say, if by some
incredible spacetime paradox,

1552
01:07:15,050 --> 01:07:17,390
Chuck Norris would ever fight
himself, he'd win, period.

1553
01:07:17,390 --> 01:07:20,112
That's hilarious.

1554
01:07:20,112 --> 01:07:23,320
We can then favorite it and say, cool,
we thought that was hilarious as heck.

1555
01:07:23,320 --> 01:07:25,710
We get an alert that says it
was favorited successfully.

1556
01:07:25,710 --> 01:07:27,260
So we might say, cool.

1557
01:07:27,260 --> 01:07:30,620
You'll get all this output here,
because we're copying quotes into a URL.

1558
01:07:30,620 --> 01:07:32,120
There are better ways of doing that.

1559
01:07:32,120 --> 01:07:35,030
But we're not going to
really discuss them here.

1560
01:07:35,030 --> 01:07:36,480
Oh, I'm a dummy.

1561
01:07:36,480 --> 01:07:41,090
Control-C, Control-L to stop
and then clear up content.

1562
01:07:41,090 --> 01:07:44,240
And then we're going to go
into stage 6 very briefly,

1563
01:07:44,240 --> 01:07:46,380
because I am roughly out of time.

1564
01:07:46,380 --> 01:07:51,830
So in stage 6, we have done a little bit
of what is roughly the right wrap-up.

1565
01:07:51,830 --> 01:07:53,810
We haven't implemented
all of the features that

1566
01:07:53,810 --> 01:07:55,020
are on the latest version.

1567
01:07:55,020 --> 01:07:56,480
You can look at those in stage 7.

1568
01:07:56,480 --> 01:07:58,300
But we have implemented quite a bit.

1569
01:07:58,300 --> 01:08:02,030
So in stage 6, we've said,
you know what, we should also

1570
01:08:02,030 --> 01:08:03,540
be able to look at the favorites.

1571
01:08:03,540 --> 01:08:05,330
We're just saving them to the database.

1572
01:08:05,330 --> 01:08:06,380
What the heck, man?

1573
01:08:06,380 --> 01:08:09,635
I want to actually understand
what our favorites were.

1574
01:08:09,635 --> 01:08:10,760
What did other people like?

1575
01:08:10,760 --> 01:08:11,426
What did I like?

1576
01:08:11,426 --> 01:08:12,420
Things like that.

1577
01:08:12,420 --> 01:08:15,930
And so we'll see, hey, we
rendered some favorites.html.

1578
01:08:15,930 --> 01:08:18,170
And you're like, oh, that makes sense.

1579
01:08:18,170 --> 01:08:20,420
And so again, we're just
extending from base.

1580
01:08:20,420 --> 01:08:22,160
This should all be fairly familiar.

1581
01:08:22,160 --> 01:08:23,870
We just changed the title to favorites.

1582
01:08:23,870 --> 01:08:27,859
And then we say, all right,
iterate through every favorite.

1583
01:08:27,859 --> 01:08:29,779
Call it favorite number whatever.

1584
01:08:29,779 --> 01:08:33,000
We're giving them some ID now so I
can use JavaScript to deal with them.

1585
01:08:33,000 --> 01:08:34,399
And we do favorite.body.

1586
01:08:34,399 --> 01:08:36,179
OK, so that's a little new.

1587
01:08:36,179 --> 01:08:39,470
And you're like, hmm, I don't know where
that might have intuitively come from.

1588
01:08:39,470 --> 01:08:41,890
And everything else
has just not changed.

1589
01:08:41,890 --> 01:08:44,850
And so I would then say, OK, cool.

1590
01:08:44,850 --> 01:08:47,140
Let's look at posts, make
sure nothing here changed.

1591
01:08:47,140 --> 01:08:48,279
Yeah, seems about right.

1592
01:08:48,279 --> 01:08:53,200
So then when we go into views.py,
index is still the same.

1593
01:08:53,200 --> 01:08:56,556
We import all the same stuff, except
we also import our models here.

1594
01:08:56,556 --> 01:08:59,430
We did that before as well, but it's
just kind of worth pointing out.

1595
01:08:59,430 --> 01:09:00,479
And we go through.

1596
01:09:00,479 --> 01:09:01,529
Posts looks right.

1597
01:09:01,529 --> 01:09:02,250
That's good.

1598
01:09:02,250 --> 01:09:04,200
Favorites, OK, that's cool.

1599
01:09:04,200 --> 01:09:06,210
Favorite objects all, huh.

1600
01:09:06,210 --> 01:09:08,819
So this is how you actually
interface with retrieving things

1601
01:09:08,819 --> 01:09:10,082
from the database in Django.

1602
01:09:10,082 --> 01:09:12,540
I always love feigning surprise
when I look at my own code.

1603
01:09:12,540 --> 01:09:14,460
I'm like, wow, that's new.

1604
01:09:14,460 --> 01:09:18,060
So basically, what we're doing here is
whenever we get to favorites, the view,

1605
01:09:18,060 --> 01:09:20,294
then we're going to say,
hey, here's our context,

1606
01:09:20,294 --> 01:09:23,460
favorites-- that makes sense, because
we remember what we wrote in our HTML.

1607
01:09:23,460 --> 01:09:24,990
And then we do favorite.objects.all.

1608
01:09:24,990 --> 01:09:29,040
And we take just all of the objects
that are in the favorites table, so

1609
01:09:29,040 --> 01:09:30,149
basically just every row.

1610
01:09:30,149 --> 01:09:35,189
You can think of this as
like select* from favorite.

1611
01:09:35,189 --> 01:09:36,750
And it just pulls them all up.

1612
01:09:36,750 --> 01:09:38,939
It gives you a query set.

1613
01:09:38,939 --> 01:09:40,479
So it's distinct from a list.

1614
01:09:40,479 --> 01:09:42,990
But it's roughly just
an iterable object that

1615
01:09:42,990 --> 01:09:45,750
contains each of those rows as
their own independent objects.

1616
01:09:45,750 --> 01:09:48,990
And because each object is
its own favorite object,

1617
01:09:48,990 --> 01:09:53,090
that's where we actually understood
that we could use, in favorites.html,

1618
01:09:53,090 --> 01:09:57,270
favorite.body, because we know that
as long as we have an actual favorite

1619
01:09:57,270 --> 01:09:59,040
object--

1620
01:09:59,040 --> 01:10:00,810
that's a little bit weird in English--

1621
01:10:00,810 --> 01:10:02,945
we can actually access
its attributes here.

1622
01:10:02,945 --> 01:10:05,070
So that's what we're going
to be allowed to render.

1623
01:10:05,070 --> 01:10:07,050
Now, we've added some favorites.

1624
01:10:07,050 --> 01:10:10,740
And you might be like, OK, but I'm
not getting it to work, Nicholas.

1625
01:10:10,740 --> 01:10:11,940
And I would agree.

1626
01:10:11,940 --> 01:10:14,740
urls.py is still really important to us.

1627
01:10:14,740 --> 01:10:16,890
We're going to want to
make sure that in path, we

1628
01:10:16,890 --> 01:10:21,930
added a way to get any request that
goes to favorites to get to the view

1629
01:10:21,930 --> 01:10:24,100
favorites and deal
something accordingly.

1630
01:10:24,100 --> 01:10:27,242
So in order to prove my point,
we're going to run server.

1631
01:10:27,242 --> 01:10:30,450
And we're going to double check there
are no unapplied migrations, because we

1632
01:10:30,450 --> 01:10:32,408
are actually interfacing
with our database now.

1633
01:10:32,408 --> 01:10:33,900
So we do need those to work.

1634
01:10:33,900 --> 01:10:37,320
And we're going to say, all
right, things should be different.

1635
01:10:37,320 --> 01:10:40,020
And this is just going to render
a bunch of quotes to us again.

1636
01:10:40,020 --> 01:10:43,720
OK, apparently, I didn't
fix this until way later.

1637
01:10:43,720 --> 01:10:45,840
And so now, you'll
notice up in our nav bar,

1638
01:10:45,840 --> 01:10:48,630
we still have home, boom, rango, boom.

1639
01:10:48,630 --> 01:10:51,210
Lorem ipsum and geeky quotes
still exist, unsurprising.

1640
01:10:51,210 --> 01:10:53,130
But favorites is now here.

1641
01:10:53,130 --> 01:10:56,160
And if we click here, we should
have some favorites saved.

1642
01:10:56,160 --> 01:10:57,230
Oh, my god.

1643
01:10:57,230 --> 01:10:59,890
There are a million tests,
because I was testing things.

1644
01:10:59,890 --> 01:11:01,750
And I guess that got saved to this.

1645
01:11:01,750 --> 01:11:06,090
And I think it's kind of cute that they
just kind of change colors randomly,

1646
01:11:06,090 --> 01:11:07,740
because I'm a derp.

1647
01:11:07,740 --> 01:11:11,070
But you'll also notice that
the things that we favorited,

1648
01:11:11,070 --> 01:11:12,750
minus this first one.

1649
01:11:12,750 --> 01:11:13,890
That was a test.

1650
01:11:13,890 --> 01:11:17,190
But these last three things
that we favorited in this demo

1651
01:11:17,190 --> 01:11:19,270
are all here, which is really cool.

1652
01:11:19,270 --> 01:11:22,710
So they are listed as the favorites IDs.

1653
01:11:22,710 --> 01:11:26,464
So this is actually the literally
32nd thing that was favorited.

1654
01:11:26,464 --> 01:11:28,380
And then if you look in
stage 7, I'm not going

1655
01:11:28,380 --> 01:11:29,796
to walk us all the way through it.

1656
01:11:29,796 --> 01:11:31,320
But I will run it.

1657
01:11:31,320 --> 01:11:35,520
Actually, it is running on
rangodjango.herokuapp.com.

1658
01:11:35,520 --> 01:11:37,650
Stage 7 implements some other features.

1659
01:11:37,650 --> 01:11:40,350
And I guess this will be
a good place to leave off.

1660
01:11:40,350 --> 01:11:44,250
It stylizes things a little bit more so
we don't have quite as much whitespace.

1661
01:11:44,250 --> 01:11:46,890
I believe it puts that
favorite icon in the middle.

1662
01:11:46,890 --> 01:11:50,190
It also wraps things in a border.

1663
01:11:50,190 --> 01:11:53,440
There's some contrived and derpy
stylistic changes that were made.

1664
01:11:53,440 --> 01:11:55,440
But if I go and favorite
this thing, it still

1665
01:11:55,440 --> 01:11:57,273
tells me that it was
favorited successfully.

1666
01:11:57,273 --> 01:12:00,420
If i into favorites, I've
actually arranged them

1667
01:12:00,420 --> 01:12:02,880
by the number of likes they've gotten.

1668
01:12:02,880 --> 01:12:05,820
And then you also have a like
button on favorites where I can--

1669
01:12:05,820 --> 01:12:07,020
this one is at 3.

1670
01:12:07,020 --> 01:12:07,710
This one's at 3.

1671
01:12:07,710 --> 01:12:08,610
This one's also at 3.

1672
01:12:08,610 --> 01:12:10,318
But if I click Like,
then that one should

1673
01:12:10,318 --> 01:12:14,649
go to the top, which is what
we'll see as soon as it reloads.

1674
01:12:14,649 --> 01:12:17,190
There are a million other ways
to do this, all in JavaScript,

1675
01:12:17,190 --> 01:12:18,064
things like that.

1676
01:12:18,064 --> 01:12:19,980
But hopefully, you've
gotten a little bit more

1677
01:12:19,980 --> 01:12:24,310
familiar with what
exactly is going on here.

1678
01:12:24,310 --> 01:12:27,660
Yeah, that concludes our whirlwind tour
of very basic web development, very

1679
01:12:27,660 --> 01:12:30,540
basic Django, and very basic Python.

1680
01:12:30,540 --> 01:12:34,740
Hopefully, you understand why I love
using Python, why I love using Django,

1681
01:12:34,740 --> 01:12:37,110
and why I think it makes
web development very easy.

1682
01:12:37,110 --> 01:12:40,650
Despite the fact that this
is not Facebook, for example,

1683
01:12:40,650 --> 01:12:42,960
and certainly not a
super aesthetic app, it

1684
01:12:42,960 --> 01:12:46,840
is definitely very cleanly written
and relatively easy to understand.

1685
01:12:46,840 --> 01:12:50,580
It also does something that is not
entirely contrived, although you

1686
01:12:50,580 --> 01:12:52,240
might look at that and go, yes, it is.

1687
01:12:52,240 --> 01:12:54,073
And I would say, yes,
you're probably right.

1688
01:12:54,073 --> 01:12:56,520
But it is something that you
can certainly build off of.

1689
01:12:56,520 --> 01:12:58,830
I encourage you to
explore Django a lot more.

1690
01:12:58,830 --> 01:13:01,226
The documentation that exist
for Django is fantastic.

1691
01:13:01,226 --> 01:13:03,600
And I don't think that I could
ask for anything better as

1692
01:13:03,600 --> 01:13:05,550
far as good documentation goes.

1693
01:13:05,550 --> 01:13:07,934
Python similarly has
fantastic documentation.

1694
01:13:07,934 --> 01:13:10,350
There are a million and one
things you can do with Django.

1695
01:13:10,350 --> 01:13:13,922
And I would recommend exploring
as many of them as possible.

1696
01:13:13,922 --> 01:13:15,630
This is also super
mobile-friendly thanks

1697
01:13:15,630 --> 01:13:17,400
to Bootstrap, so responsive design.

1698
01:13:17,400 --> 01:13:20,760
Bootstrap is another thing, great
documentation, very nice for beginners,

1699
01:13:20,760 --> 01:13:24,410
and super easy to use and customize.

1700
01:13:24,410 --> 01:13:27,210
And so all of these things,
hopefully, have demonstrated to you

1701
01:13:27,210 --> 01:13:29,310
or motivated to you why
Django is something that

1702
01:13:29,310 --> 01:13:31,020
is worth exploring and figuring out.

1703
01:13:31,020 --> 01:13:33,180
It is a fantastic Python
development framework.

1704
01:13:33,180 --> 01:13:36,240
This is all deployed on Heroku,
which is another great service.

1705
01:13:36,240 --> 01:13:37,830
I particularly love using it.

1706
01:13:37,830 --> 01:13:42,382
I swear I'm not paid by
any of these organizations.

1707
01:13:42,382 --> 01:13:44,590
And I just am kind of walking
advertisement for them,

1708
01:13:44,590 --> 01:13:47,860
because they've help me a lot
in my own personal CS career.

1709
01:13:47,860 --> 01:13:50,560
And then Waitress is another
thing that just is used underneath

1710
01:13:50,560 --> 01:13:52,240
to build all of this.

1711
01:13:52,240 --> 01:13:55,960
All of it is documented in
the GitHub repository, which I

1712
01:13:55,960 --> 01:13:59,190
guess I'll bring back up through here.

1713
01:13:59,190 --> 01:14:01,690
And so yes, you are welcome to
go and explore and see what's

1714
01:14:01,690 --> 01:14:05,590
going on in this Django whirlwind tour.

1715
01:14:05,590 --> 01:14:08,500
I did call it Django rango.

1716
01:14:08,500 --> 01:14:09,220
My apologies.

1717
01:14:09,220 --> 01:14:11,530
You had to hear that
pun, I think, 44 times--

1718
01:14:11,530 --> 01:14:12,760
42 times, sorry.

1719
01:14:12,760 --> 01:14:14,677
And so there's all of that.

1720
01:14:14,677 --> 01:14:15,760
Hopefully, you've enjoyed.

1721
01:14:15,760 --> 01:14:18,700
I really appreciate you watching
this lecture here, now, in the past,

1722
01:14:18,700 --> 01:14:21,162
and in the future.

1723
01:14:21,162 --> 01:14:23,620
And if you have any questions,
then feel free to leave them

1724
01:14:23,620 --> 01:14:25,210
in the comments in the YouTube video.

1725
01:14:25,210 --> 01:14:27,820
I am absolutely awful at answering them.

1726
01:14:27,820 --> 01:14:31,210
There are millions of
people on the internet who

1727
01:14:31,210 --> 01:14:33,370
would love to answer your questions.

1728
01:14:33,370 --> 01:14:35,950
And Stack Overflow, Google,
all sorts of great resources,

1729
01:14:35,950 --> 01:14:38,655
as well as the documentation
for each of these things.

1730
01:14:38,655 --> 01:14:43,180
So yes, this has been Nick
Wong's CS50 seminar for Django.

1731
01:14:43,180 --> 01:14:45,926
And I'm going to leave us on
this cool matrixy background,

1732
01:14:45,926 --> 01:14:47,050
because I think it's nifty.

1733
01:14:47,050 --> 01:14:47,950
Thank you very much.

1734
01:14:47,950 --> 01:14:50,100
I appreciate it.