[http-foudation] Better accept header parsing
merged branch jfsimon/accept-header-parsing (PR #5841)

This PR was squashed before being merged into the master branch (closes #5841).

Commits
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6b601bd [http-foudation] Better accept header parsing

Discussion
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[http-foudation] Better accept header parsing

Bug fix: no
Feature addition: yes
Backwards compatibility break: yes
Symfony2 tests pass: yes

**Quality:**
The special `q` item attribute represents its quality. I had to make some choices:
*  if I set `q` attribute, it's assigned to quality property, but not to attributes
*  the `__toString()` method only render `q` attribute if quality is less than 1

**BC break:**
The return of `Request::splitHttpAcceptHeader()` has changed. It's result was an array of qualities indexed by an accept value, it now returns an array of `AcceptHeaderItem` indexed by its value.

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by jfsimon at 2012-10-26T08:35:55Z

As dicussed in https://github.com/symfony/symfony/pull/5711.

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by Seldaek at 2012-10-27T10:35:49Z

Maybe you can pull https://github.com/Seldaek/symfony/commit/5e8a5267f67428e18fa6dc38cccefd9f3ca9738f into your branch (for some reason I can't send a PR to your repo, it doesn't show up in github's repo selector.. looks like they don't like projects with too many forks). It allows you to use usort() which hopefully is faster than your merge sort, though I did not bench it. I also added tests to confirm the functionality.

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by Seldaek at 2012-10-27T10:40:27Z

Sorry please check https://github.com/Seldaek/symfony/commit/376dd93c569362a162bd2e79c7eea115ac5e355e instead, I missed a few tests in the RequestTest class.

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by jfsimon at 2012-10-29T16:26:03Z

@fabpot do you think the introduced BC break is acceptable?

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by fabpot at 2012-10-29T16:37:06Z

@jfsimon Are all getAccept*() method BC?

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by jfsimon at 2012-10-29T16:39:26Z

@fabpot nope, just `Request::splitHttpAcceptHeader()`

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by jfsimon at 2012-10-29T16:43:18Z

@fabpot I think missunderstood... only `Request::splitHttpAcceptHeader()` breaks BC.

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by fabpot at 2012-10-29T16:53:22Z

So, a BC break on just splitHttpAcceptHeader is possible... but should be documented properly. Another option would be to deprecate the current method (and keep it as is), and just use the new version everywhere. Sounds better as it won"t introduce any BC breaks.

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by jfsimon at 2012-10-29T16:55:57Z

@fabpot Okay, I'll update this PR according to your second option.

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by jfsimon at 2012-10-29T20:14:46Z

@fabpot done.

As you can see here: https://github.com/symfony/symfony/pull/5841/files#L5L1029 value returned by `Request::splitHttpAcceptHeader()` is not **exactly** the same as before because all attributes are present (not only those before the `q` one).

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by fabpot at 2012-10-30T06:16:23Z

The last thing missing before I can merge is a PR to update the documentation (should probably be just a note somewhere with the example you have in the UPGRADE file).

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by jfsimon at 2012-10-30T07:07:08Z

@fabpot I could add this example here: http://symfony.com/doc/current/components/http_foundation/introduction.html#request after `Accessing the session`, what do you think?

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by fabpot at 2012-10-30T07:14:10Z

Yes, looks good to me.