The request message consists of the following:

► Request line, such as GET /images/logo.png HTTP/1.1, which requests a resource called /images/logo.png from server

► Headers, such as Accept-Language: en

► An empty line

► An optional message body

The request line and headers must all end with <CR><LF> (that is, a carriage return followed by a line feed). The empty line must consist of only <CR><LF> and no other whitespace. In the HTTP/1.1 protocol, all headers except Host are optional.

A request line containing only the path name is accepted by servers to maintain compatibility with HTTP clients before the HTTP/1.0 specification in RFC1945