Ruby on Rails Thursday, July 29, 2010

Hi all,

I am encountering some unexpected behavior in the Rails 3.0.0.rc which
I think may be incorrect.

In my controller, I have the following:

class FeedsController < ApplicationController
def recent
respond_to do |format|
format.atom
end
end
end

Likewise, I have a view (feeds/recent.atom.builder):

xml.tag!('feed', :xmlns => "http://www.w3.org/2005/Atom") do
xml.text!("...")
end

and I have a route:

match('feeds/recent' => 'feeds#recent')

If I try to fetch this with no Accept header, I get a 406 error:

$ curl -i http://localhost:3000/feeds/recent -H "Accept:"
HTTP/1.1 406 Not Acceptable
[ ... ]

This is probably not correct, since RFC 2616 (sec 14.1) reads:

| If no Accept header field is present, then it is assumed that the
| client accepts all media types.

Moving on.

If I try to fetch this with an "Accept: */*" header or "Accept:
application/atom+xml", it works as expected. Likewise all works well
if I use an "Accept: */*, text/html" header

However, if I change the order of the formats, to "Accept: text/html,
*/*", I get a 406:

$ curl -i http://localhost:3000/feeds/recent -H "Accept: text/html, */*"
HTTP/1.1 406 Not Acceptable
[ ... ]

But a "text/html, */*" Accept header should be equivalent to a "*/*,
text/html" header, since order does not matter. (This is a contrived,
but similar Accept headers are used by Firefox, with q values.)

Getting further into the bowels of RFC 2616, an "Accept:
application/*" header gives me a 406, when it should be acceptable,
because I have a response of type "application/atom+xml".

One final thing. I add a format.any entry to the controller (I am not
entirely sure the meaning of this):

def recent
respond_to do |format|
format.atom
format.any
end
end

And now I get a 200 with "Accept: */*" and "Accept:
application/atom+xml", but template errors with any other Accept
header including a "*/*".

Does anybody have any thoughts about this? It does not seem to me that
Rails is not doing the right thing here.

best, Erik Hetzner

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