Add hooks into comment/vote endpoints.

This stuff is needed for the server naming subreddit overrides.

Would love to see it replaced with custom Thing subclasses in the
future.

r2/r2/controllers/api.py

@@ -1355,6 +1355,9 @@ class ApiController(RedditController, OAuth2ResourceController):
             if not link.promoted and parent_age.days > g.REPLY_AGE_LIMIT:
                 c.errors.add(errors.TOO_OLD, field = "parent")
 
+            hooks.get_hook("comment.validate").call(sr=sr, link=link,
+                           parent_comment=parent_comment)
+
         #remove the ratelimit error if the user's karma is high
         if not should_ratelimit:
             c.errors.remove((errors.RATELIMIT, 'ratelimit'))
@@ -1550,6 +1553,8 @@ class ApiController(RedditController, OAuth2ResourceController):
         if not thing or thing._deleted:
             return
 
+        hooks.get_hook("vote.validate").call(thing=thing)
+
         if vote_info == 'rejected':
             reject_vote(thing)
             store = False

r2/r2/lib/hooks.py

@@ -43,6 +43,19 @@ class Hook(object):
         """
         return [handler(**kwargs) for handler in self.handlers]
 
+    def call_until_return(self, **kwargs):
+        """Call handlers until one returns a non-None value.
+
+        As with call, handlers are called in the same order they are
+        registered.  Only the return value of the first non-None handler is
+        returned.
+
+        """
+        for handler in self.handlers:
+            ret = handler(**kwargs)
+            if ret is not None:
+                return ret
+
 
 def get_hook(name):
     """Return the named hook `name` creating it if necessary."""

r2/r2/models/subreddit.py

@@ -50,6 +50,7 @@ from r2.models.wiki import WikiPage
 from r2.lib.merge import ConflictException
 from r2.lib.cache import CL_ONE
 from r2.lib.contrib.rcssmin import cssmin
+from r2.lib import hooks
 from r2.models.query_cache import MergedCachedQuery
 import pycassa
 
@@ -423,6 +424,12 @@ class Subreddit(Thing, Printable, BaseSite):
     def can_comment(self, user):
         if c.user_is_admin:
             return True
+
+        override = hooks.get_hook("subreddit.can_comment").call_until_return(
+                                                            sr=self, user=user)
+
+        if override is not None:
+            return override
         elif self.is_banned(user):
             return False
         elif self.type == 'gold_restricted' and user.gold: