saved searches: add 'last refreshed' column to index page.

app/models/saved_search.rb

@@ -1,5 +1,5 @@
 class SavedSearch < ApplicationRecord
-  REDIS_EXPIRY = 3600
+  REDIS_EXPIRY = 1.hour
   QUERY_LIMIT = 1000
 
   def self.enabled?
@@ -7,6 +7,8 @@ class SavedSearch < ApplicationRecord
   end
 
   concerning :Redis do
+    extend Memoist
+
     class_methods do
       extend Memoist
 
@@ -24,7 +26,7 @@ class SavedSearch < ApplicationRecord
           if redis.exists(redis_key)
             sub_ids = redis.smembers(redis_key).map(&:to_i)
             post_ids.merge(sub_ids)
-            redis.expire(redis_key, REDIS_EXPIRY)
+            redis.expire(redis_key, REDIS_EXPIRY.to_i)
           else
             PopulateSavedSearchJob.perform_later(query)
           end
@@ -32,6 +34,13 @@ class SavedSearch < ApplicationRecord
         post_ids.to_a.sort.last(QUERY_LIMIT)
       end
     end
+
+    def refreshed_at
+      ttl = SavedSearch.redis.ttl("search:#{query}")
+      return nil if ttl < 0
+      (REDIS_EXPIRY.to_i - ttl).seconds.ago
+    end
+    memoize :refreshed_at
   end
 
   concerning :Labels do
@@ -109,7 +118,7 @@ class SavedSearch < ApplicationRecord
 
           if post_ids.present?
             redis.sadd(redis_key, post_ids)
-            redis.expire(redis_key, REDIS_EXPIRY)
+            redis.expire(redis_key, REDIS_EXPIRY.to_i)
           end
         end
       end

app/views/saved_searches/index.html.erb

@@ -18,6 +18,7 @@
         <tr>
           <th data-sort="string">Query</th>
           <th data-sort="string">Labels</th>
+          <th>Last Refreshed</th>
           <th class="links"></th>
         </tr>
       </thead>
@@ -31,6 +32,13 @@
                 <%= link_to label, posts_path(:tags => "search:#{label}") %>
               <% end %>          
             </td>
+            <td>
+              <% if ss.refreshed_at.present? %>
+                <%= time_ago_in_words_tagged ss.refreshed_at %>
+              <% else %>
+                &gt;<%= SavedSearch::REDIS_EXPIRY.inspect %> ago
+              <% end %>
+            </td>
             <td class="links">
               <%= link_to "edit", edit_saved_search_path(ss) %>
                 | <%= link_to "delete", saved_search_path(ss), :method => :delete, :remote => true %>