http - Get "Content-Type" header of request in PHP

Question

I'm implementing a REST service in PHP. This service should be able to support multiple input and output formats (JSON, XML). For that reason I want to check the request headers "Accept" and "Content-Type" for the type of content sent and requested by the client.

Accessing the "Accept" header is a simple as using $_SERVER['HTTP_ACCEPT']. But accessing the "Content-Type" header seems to be a difficult task. I searched the PHP documentation and the web, but the only solution offered was the use of the PHP function apache_request_headers() which is only supported when PHP is installed as an Apache module, which is not true in my case.

So my question now: How can I access the header "Content-Type" of a request?

Answer 1

Normal (GET) requests do not have a Content-Type header. For POST requests it would appear as $_SERVER["CONTENT_TYPE"], with a value like multipart/form-data or application/x-www-form-urlencoded.

This is mandated by the CGI/1.1 specification: http://www.ietf.org/rfc/rfc3875.