Headers are not treated as case insensitive

[fragsalat]

I'm submitting a bug report

• Library Version: 1.0.0

Please tell us about your environment:

• Operating System: Ubuntu 16.04
• Node Version: 6.3.1
• NPM Version: 3.10.3
• JSPM OR Webpack AND Version any
• Browser: all | Chrome | Firefox
• Language: all

Current behavior: The current implementation of Headers isn't case-insensitive since the get(key: string) function just uses the argument as an key without any normalization. If the response header name was ETag and I try to get etag the function has(key: string) returns true because it's case insensitive, but get(key: string) returns false because it's case sensitive.

Expected/desired behavior: Regarding the RF2616 section 4.2 standard all message header names (general-, request-, response- and entity-headers) has to be handled as case insensitive.

• What is the expected behavior? With response header ETag: soemthing the function get(key: string) and has(key: string) should return true with the parameter etag, ETAG, ETag and any other case combination.
• What is the motivation / use case for changing the behavior? Firefox 49.0 seem convert the Header names in some abstruse way while Chrome 51.0.2704.79 doesn't. Therefore headers in Chrome are handled properly but not in Firefox and the other way.

[EisenbergEffect]

@fragsalat Any interest in making a PR to fix this?

[fragsalat]

@EisenbergEffect I'll do for sure :smile: But I wanted to have to many construstion sites and wait until https://github.com/aurelia/bundler/pull/144 is done first.

[EisenbergEffect]

Fantastic. Thank you!

[heruan]

This is pretty urgent: starting with the latest Chrome version (53.0.2785.143) all header names are lowercased and it breaks content-type recognition, thus breaking any Aurelia application which trusts http-client's responseType, since it accesses the header with the string Content-Type (see http-client/http-response-message.js#L81).