GET请求上的Content-Type标头是否具有惯常的语义含义？

Question

So I've been embroiled in a discussion as to the appropriate interpretation of Content-Type headers in a GET request. I plan on discarding the value of the Content-Type header on all GET requests to the service, as while it is permissible for a GET request to contain a body, server semantics for a GET request are restricted such that the body has no semantic meaning to the request.

So does the Content-Type of a GET request, which may or may not contain a message body, ever cary semantic meaning?

Can I safely discard it, or is there something I am overlooking?

Answer 1

The Content-Type of a GET request isn't useful and typically is not sent. As you state, if there is no content the type specified is irrelevant.

Conversely, the Accept header tells you what the client expects in return.

Answer 2

RFC 2616 Section 4.3 states:

The presence of a message-body in a request is signaled by the inclusion of a Content-Length or Transfer-Encoding header field in the request's message-headers. A message-body MUST NOT be included in a request if the specification of the request method (section 5.1.1) does not allow sending an entity-body in requests. A server SHOULD read and forward a message-body on any request; if the request method does not include defined semantics for an entity-body, then the message-body SHOULD be ignored when handling the request.

A GET request does not define any semantics for a message body, thus the message body, and its accompanied Content-Type if present, are to be ignored.