Mime::Type.parse ignores accept-params in the HTTP_ACCEPT header

In the case that a client sends only a single media-range but nevertheless includes accept-params, as in

Accept: text/xml; q=1

Mime::Type.parse fails to recognize this as the :xml mime type as parse just looks up the raw string in Mime::Type.lookup. See here: https://github.com/rails/rails/blob/2-3-stable/actionpack/lib/actio...

It does seem odd that a client would send a header like this, but we encountered it in real life. Reading the HTTP 1.1 spec http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html it seems that the header is valid.

This is in Rails 2.3.8. A patch is forthcoming.