Subreddit settings: Use subreddit multi for related subreddits

Use a multi to manage a subreddit's related subreddits.

r2/r2/controllers/api.py

@@ -2500,7 +2500,7 @@ class ApiController(RedditController):
             pass
         elif form.has_errors('comment_score_hide_mins', errors.BAD_NUMBER):
             pass
-        elif form.has_errors('related_subreddits',
+        elif form.has_errors('related_subreddits', errors.SUBREDDIT_NOEXIST,
                              errors.BAD_SR_NAME, errors.TOO_MANY_SUBREDDITS):
             pass
         elif form.has_errors('hide_ads', errors.GOLD_ONLY_SR_REQUIRED):

r2/r2/lib/jsontemplates.py

@@ -299,10 +299,6 @@ class SubredditJsonTemplate(ThingJsonTemplate):
             if thing.community_rules:
                 return thing.community_rules.split('\n')
             return []
-        elif attr == 'related_subreddits':
-            if thing.related_subreddits:
-                return thing.related_subreddits.split('\n')
-            return []
         else:
             return ThingJsonTemplate.thing_attr(self, thing, attr)
 
@@ -1133,6 +1129,9 @@ class SubredditSettingsTemplate(ThingJsonTemplate):
     def thing_attr(self, thing, attr):
         if attr.startswith('site.') and thing.site:
             return getattr(thing.site, attr[5:])
+        if attr == 'related_subreddits':
+            # string used for form input
+            return '\n'.join(thing.related_subreddits)
         return ThingJsonTemplate.thing_attr(self, thing, attr)
 
     def raw_data(self, thing):

r2/r2/lib/validator/validator.py

@@ -2766,11 +2766,11 @@ class VSubredditList(Validator):
 
     def run(self, subreddits):
         if not subreddits:
-            return ''
+            return []
 
         # extract subreddit name if path provided
         subreddits = [sr_path_rx.sub('\g<name>', sr.strip())
-                      for sr in subreddits.lower().splitlines()]
+                      for sr in subreddits.lower().strip().splitlines() if sr]
 
         for name in subreddits:
             valid_name = Subreddit.is_valid_name(
@@ -2778,14 +2778,19 @@ class VSubredditList(Validator):
             if not valid_name:
                 return self.set_error(errors.BAD_SR_NAME, code=400)
 
-        # unique nonempty subreddits, preserve order
-        subreddits = list(OrderedDict.fromkeys([''] + subreddits))[1:]
+        unique_srs = set(subreddits)
 
-        if len(subreddits) > self.limit:
+        if subreddits:
+            valid_srs = set(Subreddit._by_name(subreddits).keys())
+            if unique_srs - valid_srs:
+                return self.set_error(errors.SUBREDDIT_NOEXIST, code=400)
+
+        if len(unique_srs) > self.limit:
             return self.set_error(
                 errors.TOO_MANY_SUBREDDITS, {'max': self.limit}, code=400)
 
-        return '\n'.join(subreddits)
+        # return list of subreddit names as entered
+        return subreddits
 
     def param_docs(self):
         return {

r2/r2/models/subreddit.py

@@ -261,10 +261,16 @@ class Subreddit(Thing, Printable, BaseSite):
         banner_img='',
         banner_size=None,
         community_rules='',
-        related_subreddits='',
         key_color='',
         hide_ads=False,
     )
+
+    # special attributes that shouldn't set Thing data attributes because they
+    # have special setters that set other data attributes
+    _derived_attrs = (
+        'related_subreddits',
+    )
+
     _essentials = ('type', 'name', 'lang')
     _data_int_props = Thing._data_int_props + ('mod_actions', 'reported',
                                                'wiki_edit_karma', 'wiki_edit_age',
@@ -316,6 +322,12 @@ class Subreddit(Thing, Printable, BaseSite):
         ('#0079d3', N_('alien blue')),
     ])
 
+    def __setattr__(self, attr, val, make_dirty=True):
+        if attr in self._derived_attrs:
+            object.__setattr__(self, attr, val)
+        else:
+            Thing.__setattr__(self, attr, val, make_dirty=make_dirty)
+
     # note: for purposely unrenderable reddits (like promos) set author_id = -1
     @classmethod
     def _new(cls, name, title, author_id, ip, lang = g.lang, type = 'public',
@@ -557,6 +569,40 @@ class Subreddit(Thing, Printable, BaseSite):
     def hide_contributors(self):
         return self.type in {'employees_only', 'gold_only'}
 
+    @property
+    def _related_multipath(self):
+        return '/r/%s/m/related' % self.name.lower()
+
+    @property
+    def related_subreddits(self):
+        try:
+            multi = LabeledMulti._byID(self._related_multipath)
+        except tdb_cassandra.NotFound:
+            multi = None
+        return  [sr.name for sr in multi.srs] if multi else []
+
+    @related_subreddits.setter
+    def related_subreddits(self, related_subreddits):
+        try:
+            multi = LabeledMulti._byID(self._related_multipath)
+        except tdb_cassandra.NotFound:
+            if not related_subreddits:
+                return
+            multi = LabeledMulti.create(self._related_multipath, self)
+
+        if related_subreddits:
+            srs = Subreddit._by_name(related_subreddits)
+            try:
+                sr_props = {srs[sr_name]: {} for sr_name in related_subreddits}
+            except KeyError as e:
+                raise NotFound, 'Subreddit %s' % e.args[0]
+
+            multi.clear_srs()
+            multi.add_srs(sr_props)
+            multi._commit()
+        else:
+            multi.delete()
+
     def get_accounts_active(self):
         fuzzed = False
         count = AccountsActiveBySR.get_count(self)

r2/r2/templates/createsubreddit.html

@@ -478,7 +478,7 @@ try participating in other communities on reddit for a little while first before
           <a href=""></a>
           <button class="remove-sr" onclick="remove_related_sr(this.parentNode)">${_('remove')}</button>
         </li>
-        %for sr in thing.site.related_subreddits.split('\n'):
+        %for sr in thing.site.related_subreddits:
           %if sr:
             <li data-name="${sr.lower()}">
               <a href="/r/${sr}">/r/${sr}</a>
@@ -493,10 +493,11 @@ try participating in other communities on reddit for a little while first before
       </form>
       %endif
       <textarea id="related_subreddits" name="related_subreddits" style="display:none;">
-        ${keep_space(thing.site.related_subreddits)}
+        ${keep_space('\n'.join(thing.site.related_subreddits))}
       </textarea>
       ${error_field("BAD_SR_NAME", "related_subreddits")}
       ${error_field("TOO_MANY_SUBREDDITS", "related_subreddits")}
+      ${error_field("SUBREDDIT_NOEXIST", "related_subreddits")}
       <script type="text/javascript">
         function add_related_sr(form) {
           $('.SUBREDDIT_NOEXIST.field-sr').hide();