General HTTP response rules

A server may send an HTTP Redirect message (using HTTP response codes as defined in IETF RFC 2616) to an absolute URL that is different from the valid request URL that was sent by the client. HTTP Redirect causes the client to issue a new HTTP request for the new URL. Several redirects could in theory occur. Practically speaking, the redirect sequence ends when the server responds with a WMS response. The final response shall be a WMS response that corresponds exactly to the original request (or a service exception).

Response objects shall be accompanied by the appropriate Multipurpose Internet Mail Extensions (MIME) type (IETF RFC 2045) for that object. Allowable types for operation responses and service exceptions are discussed below. The basic structure of a MIME type is a string of the form "type/subtype". MIME allows additional parameters in a string of the form "type/subtype; param1=value1; param2=value2". server may include parameterized MIME types in its list of supported output formats. In addition to any parameterized variants, the server should offer the basic unparameterized version of the format.

Response objects should be accompanied by other HTTP entity headers as appropriate and to the extent possible. In particular, the Expires and Last-Modified headers provide important information for caching; Content-Length may be used by clients to know when data transmission is complete and to efficiently allocate space for results, and Content-Encoding or Content-Transfer-Encoding may be necessary for proper interpretation of the results.