Headers should be lower-cased

[opqdonut]

Currently, ring-http-response uses header names like "Content-Type". However, the ring spec defines that headers should be lower-cased: https://github.com/ring-clojure/ring/blob/master/SPEC.md#headers-1

This is important in case there are middleware in the pipeline that expect to be able to parse eg. the content-type header, and are looking for it under the "content-type" name.

I think we should label this fix as a breaking change, since somebody might've been relying on the exact naming of the headers.

[opqdonut]

Interesting, the "Content-Type" header comes directly from ring.util.response:

https://github.com/ring-clojure/ring/blob/f7dfe7c9b98c335e4573e61d94c523d5df9a6667/ring-core/src/ring/util/response.clj#L184

[opqdonut]

Let's keep this open while the original ring bug is open.

[weavejester]

Thanks for discovering this bug. The error was in the spec. It looks like when I converted it to markdown the "lowercased" adjective was added to the response header definition erroneously. I've since fixed this and the spec should now be correct.

[opqdonut]

Yeah, thanks for the clarification!

[opqdonut]

The original fix was reverted in #37