URL specifies either the URI being requested (for server requests) or the URL to access (for client requests).

For server requests the URL is parsed from the URI supplied on the Request-Line as stored in RequestURI. For most requests, fields other than Path and RawQuery will be empty. (See RFC 2616, Section 5.1.2)

For client requests, the URL's Host specifies the server to connect to, while the Request's Host field optionally specifies the Host header value to send in the HTTP request.