check for matching media type params is negated about negotiator

[jdeerhake]

I looked at this a little, but it's hard to wrap my head around the use of these params. The RFC is pretty vague about exactly how they should be used and matched against.

Searching around for content negotiation doesn't yield much information about them either. The best reference I could find are these apache docs which seem to indicate that when apache does content negotiation it only even bothers to look for a level param? The RFC says there can be multiple media range params, but it too only uses level in the examples.

I'm not really sure what should happen when there are multiple params, or whether q values should take precedence over specificity of the params?

[federomero]

Thank you @therigu and @jdeerhake.

First of all, I think this discussion is pretty theoretic because I believe these params have no real practical use (please correct me if I'm wrong).

That being said, I agree with @therigu that negotiator is not handling this case correctly. I'm not 100% convinced how it handle it though. Consider the following cases:

Let's say we have Accept: text/html;attribute=value.
Is text/html an acceptable media type? What about text/html;attribute=other?

I think strictly speaking, it should probably reject both. But maybe it's preferable to accept the first one, or maybe both. I can't really find anything on the RFC that indicates which is the right solution.

What do you guys think?

Regarding specificity vs. q value, I think specificity takes precedence.

[jdeerhake]

I tend to think that as long as they don't have the same attribute with conflicting values, then it's a match. The RFC makes it clear that if we had Accept: text/html then text/html;level=3 would be an acceptable response, so it makes sense to me that the reverse would be true.

I started to refactor it to function like that and kinda ended up rewriting the whole file. https://github.com/jdeerhake/negotiator/commit/a1e142bd81d3d91782664e0ca9131f63f8d99939

[federomero]

I don't think the reverse necessary holds. Saying Accept: text/html is like saying I want a car and Accept: text/html;level=3 is like saying I want a red car. It makes sense to me that if you ask for a car, a red car would be an acceptable response, but not the other way around.

[federomero]

I ended up handling this strictly since I think that most consistent with how content negotiation works in general.

This commit 334105a takes care of that.

Thanks