Track subreddit participation directly

The previous method of determining whether a user had interacted with a
particular subreddit (to decide whether to send them a "you've been
banned" message or not) was by checking to see whether they had any
karma (positive or negative) in the subreddit, or if they were currently
subscribed to it. This missed a fair number of cases, most significantly
that making self-posts would not count as having interacted with the
subreddit, since they have no effect on karma.

This commit uses a DenormalizedRelation to track whether a user has
interacted with the subreddit (actually *when* they last interacted with
it, though that data is currently unused). It adds one new type of
action that is considered interaction - sending a modmail to the
subreddit.  It also removes the error/warning from the ban page about
trying to send a ban message to someone that has never interacted with
the subreddit, since that should no longer really be a concern.

r2/r2/controllers/api.py

@@ -1041,13 +1041,6 @@ def POST_friend(self, form, jquery, friend,
         if type == "banned":
             if form.has_errors("ban_message", errors.TOO_LONG):
                 return
-
-            # don't let them ban with a custom message if the user won't
-            # actually be messaged
-            if ban_message and not friend.has_interacted_with(container):
-                c.errors.add(errors.USER_BAN_NO_MESSAGE, field="ban_message")
-                form.set_error(errors.USER_BAN_NO_MESSAGE, "ban_message")
-                return
         else:
             ban_message = None
 
@@ -3365,6 +3358,8 @@ def POST_subscribe(self, action, sr):
             Subreddit.subscribe_defaults(c.user)
 
             if action == "sub":
+                SubredditParticipationByAccount.mark_participated(c.user, sr)
+
                 if sr.add_subscriber(c.user):
                     sr._incr('_ups', 1)
                 else:

r2/r2/lib/db/tdb_cassandra.py

@@ -34,6 +34,7 @@
 from pycassa.system_manager import (
     ASCII_TYPE,
     COUNTER_COLUMN_TYPE,
+    DATE_TYPE,
     INT_TYPE,
     SystemManager,
     TIME_UUID_TYPE,

r2/r2/lib/errors.py

@@ -157,7 +157,6 @@
         ('SCRAPER_ERROR', _("unable to scrape provided url")),
         ('NO_SR_TO_SR_MESSAGE', _("can't send a message from a subreddit to another subreddit")),
         ('USER_BLOCKED_MESSAGE', _("can't send message to that user")),
-        ('USER_BAN_NO_MESSAGE', _("that user will not be sent a ban notification, remove note to be able to ban")),
         ('ADMIN_REQUIRED', _("you must be in admin mode for this")),
         ('CANT_CONVERT_TO_GOLD_ONLY', _("to convert an existing subreddit to gold only, send a message to %(admin_modmail)s") 
             % dict(admin_modmail=g.admin_message_acct)),

r2/r2/models/account.py

@@ -165,17 +165,12 @@ def __ne__(self, other):
         return not self.__eq__(other)
 
     def has_interacted_with(self, sr):
-        if not sr:
+        try:
+            r = SubredditParticipationByAccount.fast_query(self, [sr])
+        except tdb_cassandra.NotFound:
             return False
 
-        for type in ('link', 'comment'):
-            if hasattr(self, "%s_%s_karma" % (sr.name, type)):
-                return True
-
-        if sr.is_subscriber(self):
-            return True
-
-        return False
+        return (self, sr) in r
 
     def karma(self, kind, sr = None):
         suffix = '_' + kind + '_karma'
@@ -1067,3 +1062,21 @@ def get_accounts(cls, email_address):
             return []
         account_id36s = cls.get_time_sorted_columns(canonical).keys()
         return Account._byID36(account_id36s, data=True, return_dict=False)
+
+
+class SubredditParticipationByAccount(tdb_cassandra.DenormalizedRelation):
+    _use_db = True
+    _write_last_modified = False
+    _views = []
+    _extra_schema_creation_args = {
+        "key_validation_class": tdb_cassandra.ASCII_TYPE,
+        "default_validation_class": tdb_cassandra.DATE_TYPE,
+    }
+
+    @classmethod
+    def value_for(cls, thing1, thing2):
+        return datetime.now(g.tz)
+
+    @classmethod
+    def mark_participated(cls, account, subreddit):
+        cls.create(account, [subreddit])

r2/r2/models/link.py

@@ -32,7 +32,12 @@
     tup,
     UrlParser,
 )
-from account import Account, DeletedUser, BlockedSubredditsByAccount
+from account import (
+    Account,
+    BlockedSubredditsByAccount,
+    DeletedUser,
+    SubredditParticipationByAccount,
+)
 from subreddit import DefaultSR, DomainSR, Subreddit
 from printable import Printable
 from r2.config import extensions
@@ -210,6 +215,7 @@ def _submit(cls, title, url, author, sr, ip, spam=False, sendreplies=True):
         l._commit()
         l.set_url_cache()
         LinksByAccount.add_link(author, l)
+        SubredditParticipationByAccount.mark_participated(author, sr)
         if author._spam:
             g.stats.simple_event('spam.autoremove.link')
             admintools.spam(l, banner='banned user')
@@ -1000,6 +1006,8 @@ def _new(cls, author, link, parent, body, ip):
             link.update_search_index(boost_only=True)
 
         CommentsByAccount.add_comment(author, c)
+        SubredditParticipationByAccount.mark_participated(
+            author, c.subreddit_slow)
 
         def should_send():
             # don't send the message to author if replying to own comment
@@ -1651,6 +1659,9 @@ def _new(cls, author, to, subject, body, ip, parent=None, sr=None,
         if sr_id and not sr:
             sr = Subreddit._byID(sr_id)
 
+        if to_subreddit:
+            SubredditParticipationByAccount.mark_participated(author, sr)
+
         inbox_rel = []
 
         inbox_hook = hooks.get_hook("message.skip_inbox")

r2/r2/public/static/css/reddit.less

@@ -8211,13 +8211,6 @@ form#banned textarea {
     margin-left: 0;
 }
 
-div.usertable .note {
-  color: #808080;
-  font-size: 0.8em;
-  white-space: normal;
-  margin-bottom: 10px;
-}
-
 .gold-accent h1,
 .gold-accent th {
     color: #6a4d00;

r2/r2/templates/userlisting.html

@@ -36,11 +36,6 @@ <h1>${title}</h1>
     <input type="hidden" name="action" value="add">
     <input type="hidden" name="container" value="${container_name}">
     <input type="hidden" name="type" value="${add_type}">
-    %if add_type == "banned":
-      <div class="note">
-        ${_("note: the banned user will only receive a message notifying them of their ban if they are subscribed to the subreddit or have previously gained or lost any karma (either link or comment) in the subreddit.")}
-      </div>
-    %endif
     %if add_type in ("banned", "wikibanned"):
         <label for="name">${_('who to ban?')} &nbsp;</label>
         <input type="text" class="friend-name" name="name" id="name">
@@ -75,7 +70,6 @@ <h1>${title}</h1>
     ${error_field("USER_DOESNT_EXIST", "name")}
     ${error_field("ALREADY_MODERATOR", "name")}
     ${error_field("BANNED_FROM_SUBREDDIT", "name")}
-    ${error_field("USER_BAN_NO_MESSAGE", "ban_message")}
     %if caller:
       ${caller.body()}
     %endif