HTTP request

A HTTP request message from a client to a server includes, within the first line of that message, the method to be applied to the resource, the identifier of the resource, and the protocol version in use.

Each HTTP request consists of 3 sections: request line, headers and body. An HTTP client sends an HTTP request to a server in the form of a request message.

Whenever your web browser fetches a file (a page, a picture, etc) from a web server, it does so using HTTP – that’s "Hypertext Transfer Protocol". HTTP is a request/response protocol, which means your computer sends a request for some file (e.g. "Get me the file ‘home.html’"), and the web server sends back a response ("Here’s the file", followed by the file itself).

That request which your computer sends to the web server contains all sorts of (potentially) interesting information. We’ll now examine the HTTP request your computer just sent to this web server, see what it contains, and find out what it tells me about you.

HTTP request includes following format:

• A Request-line

• Zero or more header (General|Request|Entity) fields followed by CRLF

• An empty line (i.e., a line with nothing preceding the CRLF) indicating the end of the header fields

• Optionally a message-body

The following sections explain each of the entities used in an HTTP request message.