Header type equality comparison

[psibi]

The equality comparison is case insensitive according to the HTTP specs. Right now, we don't make that distinction.

[snoyberg]

Header keys are wrapped in the CI type constructor, which ensures a case insensitive comparison. Is there a specific counterexample?

[psibi]

@snoyberg I think this Header is not wrapped in CI type constructor: https://www.stackage.org/haddock/lts-8.22/yesod-core-1.4.35/Yesod-Core.html#t:Header

[psibi]

I think it would be better to just wrap it in CI type constructor instead of doing Eq instance fix.

[paul-rouse]

At the moment the code in #1417 would still need to be changed to use Eq on Header - does this actually go any wider than that code, or would it be best just to use CI for case-insensitivity there, for that one comparison?

[psibi]

I would vote for using CI for case-insensitivity there as that's the most easiest thing to do. :)

[snoyberg]

@psibi Up until now, there has been no comparison performed there that I'm aware of. 20/20 hindsight, it would make sense to use CI ByteString, but I'd rather not break the API for this.