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DAVID MALAN: So for
this problem set, you're

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going to implement your
very own web server.

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We've provided you with a bit of
skeleton code that gets you started,

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but ultimately, you're
going to finish it

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up so that it actually
implements the ability

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to serve up web pages, both static
content and also dynamic content,

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via PHP.

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>> Let's take a look, first by
way of the staff solution,

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at what the final result is going to be.

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I'm first going to run
tilda cs50/pset6/server

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and then dash p to specify
a port and then a number

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like 8080, which is pretty common.

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And then the name or
the path to directory

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that I want to use as the web
server's route, where all of the files

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are going to be served up from.

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I'm going to go ahead and hit Enter.

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And you'll see in color text
here that the web server is

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using my public directory and
it's listening on port 8080.

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Now let's go over to a web
browser and actually try

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to connect to this website.

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Notice in the bottom right
hand corner of your appliance,

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that there's been all
this time an IP address.

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That's a unique identifier
for your computer

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that identifies it so
that you can access it

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via web browser or any
number of other tools.

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So I'm going to go ahead and
open up Chrome in the appliance

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and I'm going to visit
http://172.16.254.133 and then

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colon 8080.

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And the colon's important because if
you don't specify that port that I also

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specified at the command
line, you're actually

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going to be talking into
the appliance's own web

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server called Apache,
which is built into it.

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But today we want to focus
on our own web server.

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>> So now when I hit Enter,
you'll notice that 501

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Not Implemented comes
up because I've tried

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to access a directory,
not a particular file.

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Indeed, if you look over to
the left in my terminal window,

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you'll see that while
listening on port 8080,

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the web server saw a request for
GET/HTTP/1.1 and then the web server

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responded, as pictured here in
red, with that 501 Not Implemented.

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>> Curiously though, there's also
this second line in white,

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GET/favicon.ico HTTP/1.1.

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Now I definitely didn't do that
myself, but it turns out that Chrome,

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like a lot of browsers, will
presumptuously assume that your website

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is supposed to have a little
graphical icon up in the tab or next

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to the address bar, like a Harvard
crest or something along those lines,

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and so it's just guessing by
way of this default file name,

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that you might have a file
like that too, which we don't.

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And so 404 Not Found gets spit back.

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>> Well now, notice this.

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In addition to visiting
this address inside

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of the appliance, 172.16.254.133:8080,
but your IP address, to be clear,

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will be different.

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Notice that if I go on my Mac
or my PC to my own browser

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and visit that same URL, I can
see from my own preferred browser

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whether it's Chrome or Firefox
or IE or something else, exactly

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the same results.

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>> OK.

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Let's actually visit a URL that's known
to exist in that public directory.

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Namely, the IP address
colon 8080/cat.jpg.

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Enter.

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And there, indeed, is Happy Cat.

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I know in advance that there's also
a cat.HTLM file, so if I hit Enter,

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I see that one as well.

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And notice, in the
meantime, on the left we

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have a whole bunch of
green outputs signifying

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that these were 200 statuses,
which means they were OK.

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