Dynamic cookie domain per request

[braindeaf]

Motivation / Background

We've recently been looking at authentication across multiple applications where a multi-tenanted application needs to set a specific cookie domain e.g .tenant1.company.name for the application. Since this needs to work across multiple applications whether it be auth.tenant1.company.name, jam.tenant1.company.name we need just a little more flexibility and the :tld_length option won't cut it. Hence using a proc to set the cookie domain.

This pull request allows option[:domain] to be a proc

Detail

This is a small change to actionpack/lib/action_dispatch/middleware/cookies.rb, coping with that additional option.

Checklist

Before submitting the PR make sure the following are checked:

• This Pull Request is related to one change. Changes that are unrelated should be opened in separate PRs.
• Commit message has a detailed description of what changed and why. If this PR fixes a related issue include it in the commit message. Ex: [Fix #issue-number]
• Tests are added or updated if you fix a bug or add a feature.
• CHANGELOG files are updated for the changed libraries if there is a behavior change or additional feature. Minor bug fixes and documentation changes should not be included.

[ghiculescu]

Thanks for the PR. Could you please update the changelog, and squash your commits down to one?

[braindeaf]

@ghiculescu Added the CHANGELOG, just tried to squash into a single commit and now I've got 5 commits total :S. I don't think I've had to squash within the same branch before, only at the point of merging a PR from one branch to another.

[braindeaf]

Scratch that, I've sorted it :)

[byroot]

LGTM. Can you rebase to fix the conflict and let me know?

[braindeaf]

Sorry @byroot busy day. Rebased now :)

[byroot]

No worries, there was no rush. Thanks for the PR!