Add options to disable comments, the forum, and autocomplete. This is
for personal boorus and potentially for safe mode. Note that disabling
the forum may cause difficulties with creating and approving BURs.
Disabling comments and the forum merely hides them from most areas,
rather than completely removing them.
Refactor controllers so that endpoint rate limits are declared locally,
with the endpoint, instead of globally, in a single method in ApplicationController.
This way an endpoint's rate limit is declared in the same file as the
endpoint itself.
This is so we can add fine-grained rate limits for certain GET requests.
Before rate limits were only for non-GET requests.
* Tie rate limits to both the user's ID and their IP address.
* Make each endpoint have separate rate limits. This means that, for
example, your post edit rate limit is separate from your post vote
rate limit. Before all write actions had a shared rate limit.
* Make all write endpoints have rate limits. Before some endpoints, such
as voting, favoriting, commenting, or forum posting, weren't subject
to rate limits.
* Add stricter rate limits for some endpoints:
** 1 per 5 minutes for creating new accounts.
** 1 per minute for login attempts, changing your email address, or
for creating mod reports.
** 1 per minute for sending dmails, creating comments, creating forum
posts, or creating forum topics.
** 1 per second for voting, favoriting, or disapproving posts.
** These rate limits all have burst factors high enough that they
shouldn't affect normal, non-automated users.
* Raise the default write rate limit for Gold users from 2 per second to
4 per second, for all other actions not listed above.
* Raise the default burst factor to 200 for all other actions not listed
above. Before it was 10 for Members, 30 for Gold, and 60 for Platinum.
Rework the rate limit implementation to make it more flexible:
* Allow setting different rate limits for different actions. Before we
had a single rate limit for all write actions. Now different
controller endpoints can have different limits.
* Allow actions to be rate limited by user ID, by IP address, or both.
Before actions were only limited by user ID, which meant non-logged-in
actions like creating new accounts or attempting to login couldn't be rate
limited. Also, because actions were limited by user ID only, you could
use multiple accounts with the same IP to get around limits.
Other changes:
* Remove the API Limit field from user profile pages.
* Remove the `remaining_api_limit` field from the `/profile.json` endpoint.
* Rename the `X-Api-Limit` header to `X-Rate-Limit` and change it from a
number to a JSON object containing all the rate limit info
(including the refill rate, the burst factor, the cost of the call,
and the current limits).
* Fix a potential race condition where, if you flooded requests fast
enough, you could exceed the rate limit. This was because we checked
and updated the rate limit in two separate steps, which was racy;
simultaneous requests could pass the check before the update happened.
The new code uses some tricky SQL to check and update multiple limits
in a single statement.