HTTP protocol

HTTP message format

The HTTP generic message format is as follows:

<start-line>
<message-headers>
<empty-line>
[<message-body>]
[<message-trailers>]

HTTP Request message format

<request-line>: <METHOD> <request-uri> <HTTP-VERSION>
<general-headers>: 
<request-headers>
<entity-headers>
<empty-line>
[<message-body>]
[<message-trailers>]

http request message format

To know more about METHOD, link

HTTP Response message format

<status-line>: <HTTP-VERSION> <status-code> <reason-phrase>
<general-headers>
<response-headers>
<entity-headers>
<empty-line>
[<message-body>]
[<message-trailers>]

http response message format

To know more about status-code : reason-phrase, link

Multiple HTTP request over one TCP session

Chunked transfer

<chunk-1-length>
<chunk-1-data>
<chunk-2-length>
<chunk-2-data>
...
0
<message-trailers>

Example HTTP Response Using Content-Length Header

HTTP/1.1 200 OK
Date: Mon, 22 Mar 2004 11:15:03 GMT
Content-Type: text/html
Content-Length: 129
Expires: Sat, 27 Mar 2004 21:12:00 GMT

<html><body><p>The file you requested is 3,400 bytes long and was last modified: Sat, 20 Mar 2004 21:12:00 GMT.</p></body></html>

Example HTTP Response Using Chunked Transfer Encoding

HTTP/1.1 200 OK
Date: Mon, 22 Mar 2004 11:15:03 GMT
Content-Type: text/html
Transfer-Encoding: chunked
Trailer: Expires

29
<html><body><p>The file you requested is 
5
3,400
23
bytes long and was last modified: 
1d
Sat, 20 Mar 2004 21:12:00 GMT
13
.</p></body></html>
0
Expires: Sat, 27 Mar 2004 21:12:00 GMT