Add utm query parameters onto links for comments/messages

Link.tracking_link adds utm query parameters onto links inside reddit
to track which button was clicked, what component type contains the button
(e.g. post listing, inbox, post listing embedded on a comments page),
what page type the user is visiting, and the page's subreddit.

This feature is enabled via feature flag and disabled by admin mode.

This commit affects programmatically-generated links to comments and messages.

Author: jewel-andraia

r2/example.ini

@@ -963,3 +963,4 @@ feature_mobile_native_targeting = {"employee": true}
 feature_pause_ads = on
 feature_ads_auction = {"employee": true}
 feature_cpc_pricing = off
+feature_utm_comment_links = off

r2/r2/lib/pages/pages.py

@@ -1991,7 +1991,7 @@ def cache_key(self):
         elif num > 100:
             num = (num / 10) * 10
 
-        _id = make_key_id(
+        cache_key_args = [
             self.article._fullname,
             self.article.contest_mode,
             self.article.locked,
@@ -2007,7 +2007,12 @@ def cache_key(self):
             c.can_embed,
             self.max_depth,
             self.edits_visible,
-        )
+        ]
+
+        if feature.is_enabled("utm_comment_links"):
+            cache_key_args.append("utm_comment_links")
+
+        _id = make_key_id(*cache_key_args)
         key = "pane:%s" % _id
         return key
 

r2/r2/models/link.py

@@ -28,6 +28,9 @@
     Thing, Relation, NotFound, MultiRelation, CreationError)
 from r2.lib.db.operators import desc
 from r2.lib.errors import RedditError
+from r2.lib.tracking import (
+    get_site,
+)
 from r2.lib.utils import (
     base_url,
     domain,
@@ -471,6 +474,62 @@ def markdown_link_slow(self):
         title = title.replace("]", r"\]")
         return "[%s](%s)" % (title, self.make_permalink_slow())
 
+    @classmethod
+    def tracking_link(cls,
+                      link,
+                      wrapped_thing=None,
+                      element_name=None,
+                      context=None,
+                      site_name=None):
+        """Add utm query parameters to reddit.com links to track navigation.
+
+        context => ?utm_medium (listing page, post listing on hybrid page)
+        site_name => ?utm_name (subreddit that user is currently browsing)
+        element_name => ?utm_content (what element leads to this link)
+        """
+
+        if (c.user_is_admin or
+                not feature.is_enabled('utm_comment_links')):
+            return link
+
+        urlparser = UrlParser(link)
+        if not urlparser.path:
+            # `href="#some_anchor"`
+            return link
+        if urlparser.scheme == 'javascript':
+            return link
+        if not urlparser.is_reddit_url():
+            return link
+
+        query_params = {}
+
+        query_params["utm_source"] = "reddit"
+
+        if context is None:
+            if (hasattr(wrapped_thing, 'context') and
+                    wrapped_thing.context != cls.get_default_context()):
+                context = wrapped_thing.context
+            else:
+                context = request.route_dict["controller"]
+        if context:
+            query_params["utm_medium"] = context
+
+        if element_name:
+            query_params["utm_content"] = element_name
+
+        if site_name is None:
+            site_name = get_site()
+        if site_name:
+            query_params["utm_name"] = site_name
+
+        query_params = {k: v for (k, v) in query_params.iteritems() if (
+                        v is not None)}
+
+        if query_params:
+            urlparser.update_query(**query_params)
+            return urlparser.unparse()
+        return link
+
     def _gild(self, user):
         now = datetime.now(g.tz)
 
@@ -885,6 +944,10 @@ def add_props(cls, user, wrapped):
         # Run this last
         Printable.add_props(user, wrapped)
 
+    @classmethod
+    def get_default_context(cls):
+        return request.route_dict["action_name"]
+
     @property
     def post_hint(self):
         """Returns a string that suggests the content of this link.

r2/r2/models/subreddit.py

@@ -1777,6 +1777,7 @@ def __init__(self):
 
 
 class _DefaultSR(FakeSubreddit):
+    analytics_name = 'frontpage'
     #notice the space before reddit.com
     name = ' reddit.com'
     path = '/'

r2/r2/templates/comment.html

@@ -44,7 +44,10 @@
 </%def>
 
 <%def name="link()" buffered="True">
-  <a href="${thing.link.url}" class="title"
+  <%
+    url = thing.link.tracking_link(thing.link.url, thing, "title", site_name=False)
+  %>
+  <a href="${url}" class="title"
      %if thing.nofollow:
        rel="nofollow"
      %endif

r2/r2/templates/link.html

@@ -49,10 +49,11 @@
 <%def name="make_link(name, css_class, tabindex=0)">
   <%
     media_override = thing.link_child and getattr(thing, 'media_override', False)
+    url = thing.tracking_link(thing.href_url, thing, name)
   %>
   <a class="${css_class} may-blank ${ c.user_is_loggedin and 'loggedin' or ''}
             ${ media_override and 'open-expando' or '' }"
-     href="${thing.href_url}"
+     href="${url}"
      %if tabindex:
        tabindex="${tabindex}"
      %endif

r2/r2/templates/morerecursion.html

@@ -21,10 +21,13 @@
 ###############################################################################
 
 <%inherit file="comment_skeleton.html"/>
+<%!
+    from r2.models import Link
+%>
 
 
 <%def name="commentBody()">
-<span class="deepthread"><a href="${thing.parent_permalink}">${_("continue this thread")}</a></span>
+<span class="deepthread"><a href="${Link.tracking_link(thing.parent_permalink, thing, context='continue_thread')}">${_("continue this thread")}</a></span>
 </%def>
 
 <%def name="midcol(cls='')">

r2/r2/templates/printablebuttons.html

@@ -763,7 +763,7 @@
   <% data_attrs = {"event-action": event_action} if event_action else None %>
   ${plain_link(
       title,
-      link,
+      Link.tracking_link(link, thing, element_name=event_action),
       _class=a_class,
       rel="nofollow",
       _sr_path=sr_path,

r2/r2/templates/trendingsubredditsbar.html

@@ -20,14 +20,18 @@
 ## reddit Inc. All Rights Reserved.
 ###############################################################################
 
+<%!
+    from r2.models import Link
+%>
+
 <div class="trending-subreddits">
   <div class="rank-spacer"></div>
   <div class="midcol-spacer"></div>
   <div class="trending-subreddits-content">
     <strong>${_('trending subreddits')}</strong>
     <ul>
     %for i, subreddit_name in enumerate(thing.subreddit_names):
-      <li><a href="/r/${subreddit_name}?ref=trending_sr_${i+1}" target="_blank">/r/${subreddit_name}</a></li>
+      <li><a href="${Link.tracking_link('/r/%s'%subreddit_name, context='trending_subreddits_bar', element_name='trending_sr_%s'%(i+1))}" target="_blank">/r/${subreddit_name}</a></li>
     %endfor
     </ul>
     <a href="${thing.comment_url}" class="${thing.comment_label_cls}">${thing.comment_label}</a>