- Introduction to HTTP 1:22
- Building a Case for HTTP 2:41
- Intro to HTTP 2 questions
- HTTP Requests Using Telnet 7:08
- HTTP Request Format 3:01
- HTTP Headers 1 question
- HTTP Response Format 3:42
- HTTP Response Format 1 question
- Sending Data with a GET Request 4:11
- Sending Data with a GET Request 1 question
- Sending Data with a POST Request 5:57
- Sending Data with a POST Request 1 question
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HTTP Request Format
3:01Now that you've seen HTTP in action, it's time to cover the details of both the request and the subsequent response. In this video, we cover the format of the request. In general, there are four parts: (1) the request line, (2) a series of headers with name/value pairs on separate lines, (3) a blank line, and (4) if the request is a POST request, a body or payload.
Now that you've seen a few sample
HTTP requests using telnet,
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I'd like to show you the overall
format of an HTTP request
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as stated in the specifications which
I've linked to in the teacher's notes.
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Here's how an HTTP request needs to look.
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HTTP request begin with request line.
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This starts with what's called
the request method, get or post.
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Know that there are other request
methods available on HTTP.
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They're outside the scope
of this course but
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I've linked to them in
case you're curious.
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In general the get request
method is used when you want to
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view a resource on the server
without making any changes.
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And post request are used for
actually making a change or
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update to the listed resource.
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We'll look at post request
later in the course.
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Speaking of the resource,
that's what's listed next, the URI, or
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again, Uniform Resource Identifier.
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If you want to view the root, or
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what's typically the home page,
you'll use a single slash here.
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Finally, HTTP is listed as the protocol
in use followed by a slash and
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ending with the version of HTTP,
currently 1.1.
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As a side note and heads up,
HTTP/2 is on the way.
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Don't worry though,
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HTTP/2 won't change any of the stuff
we're discussing in this course.
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And you'll be able to continue using
HTTP/1.1 likely for many years to come.
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For more info on HTTP/2,
check the teacher's notes.
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The next line begins with what's called
the header section of the request.
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This communicates information related
to the request being made, and
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can include all sorts of info.
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In this example, you see it includes
the host which we've discussed.
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The user agent which identifies
the exact device making the request
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I've listed telnet here and
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accept language which tells the server
which language we prefer for the response.
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There are lots of other
headers available and
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we'll see a bunch more throughout
the best of the course.
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Following the headers is a blank line.
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Then concluding the request,
is the request body, or
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what's frequently called the payload.
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If the headers refer to the information
related to the request,
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the payload refers to the data being
transferred in the request, if any.
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As we'll see, data needs to be transferred
when the purpose of the request
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is to change a resource on the server.
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For example,
consider the scenario of using a form to
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edit the first name of a contact
saved in your address book online.
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When you submit those changes,
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a post request is sent containing
the new first name in the payload.
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In general,
the exact changes to be made on the server
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will be contained in the payload
of the post request.
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You won't see a payload
in the get request.
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And there you have it,
the format for any HTTP request.
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With that said,
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let's turn to the other side of this
web conversation, the response.
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