Expose the user's permissions through a header

[RubenVerborgh]

Implements #246 with WAC-Allow: user="read write append",public="read".

[csarven]

Good stuff!

Would "WAC-Mode" be preferable just to keep it closer to *nix's mode bits?

[RubenVerborgh]

@csarven The header name was chosen in a discussion with @timbl and @dmitrizagidulin yesterday (see #246). I don't mind the naming either way (although I still think "WAC" is cryptic).

[dmitrizagidulin]

I just realized we want to do WAC-Allow, minus the ed on the end. (To match the HTTP Allow: header). Sorry bout that :)

[timbl]

On the whiteboard we had spaces or commas to separate the modes, to mimic other headers. In this code we have semicolons... was that a conscious decision?

[RubenVerborgh]

Which of these would you prefer? I don't mind either way; I was following what @dmitrizagidulin wrote down of our discussion in #246.

[csarven]

To stick close to convention (like in Web Linking for relation types), probably best to use space as a delimiter. Plus, it is easier to read.

[RubenVerborgh]

Makes sense! Are the quotes needed?

[csarven]

I think the quotes might make it easier for consumers to tokenise. It can also help to escape characters or have specialised modes or something in the future.

[RubenVerborgh]

Okay, mandatory quotes it is.

[RubenVerborgh]

250e513 brings spaces.

[RubenVerborgh]

Currently on hold because of #552.

[RubenVerborgh]

#552 has been merged, so this one is ready for review and merge.

[dmitrizagidulin]

This has been a much-requested feature! Nicely done!