[Improvement] Add params to Challenge

At the moment, Challenge only contains the auth scheme name and realm. To provide authentication other than Basic, this is not enough. For instance, for Digest auth, there are various parameters which have to be parsed and processed.

I suggest to improve the Challenge class so that it contains not only auth scheme name and realm, but also a list of auth parameters, so that implementors don’t have to parse WWW-Authenticate again and can use okhttp’s Challenge instead, which would reduce redundancy. Logically, it sounds reasonable for me that a HTTP framework prepares authentication challenges in a way that they’re already usable by authenticators.

For a suggested layout of Challenge, please have a look at this HttpUtils.AuthScheme. It contains the auth scheme name, parsed unnamed parameters and parsed named parameters.

For a suggested parsing algorithm of WWW-Authenticate that generates such parameterized challenge instances, please see HttpUtils.parseWwwAuthenticate and its tests. It handles challenges without parameters, with RFC-compliant parameters (param=value), and with unnamed parameters (like used in Negotiate).

[rfc2822]

Yes, the dav4android methods are designed to be independent of the actual authentication method.

To implement my suggestion, I’d

• enhance Challenge to also store unnamed and named parameters so that authenticators can use response.challanges() to get all required information without parsing headers itself;
• change the List<Challenge> parseChallenges(Headers responseHeaders, String challengeHeader) method so that it extracts name and parameters from challengeHeader.

[swankjesse]

Fixed by https://github.com/square/okhttp/pull/4252