Summary:
Ref T12612. This updates the rate limiting code to:
- Support a customizable token, like the client's X-Forwarded-For address, rather than always using `REMOTE_ADDR`.
- Support APCu.
- Report a little more rate limiting information.
- Not reference nonexistent documentation (removed in D16403).
I'm planning to put this into production on `secure` for now and then we can deploy it more broadly if things work well.
Test Plan:
- Enabled it locally, used `ab -n 100` to hit the limit, saw the limit enforced.
- Waited a while, was allowed to browse again.
Reviewers: chad, amckinley
Reviewed By: amckinley
Maniphest Tasks: T12612
Differential Revision: https://secure.phabricator.com/D17758
3698e4a14f