Package documentation URL not compatible with hoogle/old hackage

[bennofs]

Currently, hoogle generates URLs like the following:

http://hackage.haskell.org/package/HUnit/docs/Test-HUnit-Base.html#v:test

This is no longer a valid URL with hackage2. Should the documentation URLs be compatible with old hackage?

[aslatter]

It looks like we have a redirect in place from http://beta.hackage.haskell.org/packages/archive/QuickCheck/latest/doc/html/Test-QuickCheck-Test.html#v:test to http://beta.hackage.haskell.org/package/QuickCheck/docs/Test-QuickCheck-Test.html#v:test except that the second URL doesn't work.

The following link does work, however: http://beta.hackage.haskell.org/package/QuickCheck-2.6/docs/Test-QuickCheck-Test.html .

I think we used to be able to get from the "docs with no version" path to the "most recent version of docs", but that must have disappeared at some point.

[dcoutts]

BTW, to avoid other people being confused, hoogle actually points to:

http://hackage.haskell.org/packages/archive/HUnit/latest/doc/html/Test-HUnit-Base.html#v:test

@aslatter Right, we could add in a redirect from the unversioned link. Notice that we actually do have a redirect from http://beta.hackage.haskell.org/package/QuickCheck/docs/ but it goes into an infinte redirect loop...

So looks like all we have to do is fix that and while we're at it make things below that redirect too, and we're sorted.

[dcoutts]

BTW, a related problem is that search engines etc always index a specific version of the docs and then in practice that means users going via google get sent to an older version of the docs than necessary. It'd be nice if we could think of some way to encourage search engines to give people the unversioned links.

[aslatter]

It looks like we can specify a canonical URL in HTTP headers:
https://support.google.com/webmasters/answer/139394?hl=en

That we would only do this for the most-recent set of haddocks.

[dcoutts]

@aslatter yes I'm aware of the rel=canonical thing, but it's not clear to me that it would help us here. We would have to use canonical to point to a url that does a temporary redirect. I fear the google indexer would not like us.

[dcoutts]

Fixed and code running on the sever.