Implements MongoidExt::Tags module using mongodb's aggregation framework

Signed-off-by: Jorge Cuadrado <kuadrosxx@gmail.com>

Gemfile.lock

@@ -1,18 +1,18 @@
 GEM
   remote: http://rubygems.org/
   specs:
-    activemodel (3.2.7)
-      activesupport (= 3.2.7)
+    activemodel (3.2.12)
+      activesupport (= 3.2.12)
       builder (~> 3.0.0)
-    activesupport (3.2.7)
+    activesupport (3.2.12)
       i18n (~> 0.6)
       multi_json (~> 1.0)
-    builder (3.0.0)
+    builder (3.0.4)
     coderay (1.0.7)
     differ (0.1.2)
     encryptor (1.1.3)
     git (1.2.5)
-    i18n (0.6.0)
+    i18n (0.6.4)
     jeweler (1.8.4)
       bundler (~> 1.0)
       git (>= 1.2.5)
@@ -22,20 +22,20 @@ GEM
     json (1.7.4)
     metaclass (0.0.1)
     method_source (0.8)
-    mime-types (1.19)
+    mime-types (1.21)
     mocha (0.11.4)
       metaclass (~> 0.0.1)
-    mongoid (3.0.2)
-      activemodel (~> 3.1)
-      moped (~> 1.1.3)
-      origin (~> 1.0.3)
+    mongoid (3.1.2)
+      activemodel (~> 3.2)
+      moped (~> 1.4.2)
+      origin (~> 1.0)
       tzinfo (~> 0.3.22)
-    mongoid-grid_fs (1.3.1)
+    mongoid-grid_fs (1.7.0)
       mime-types (~> 1.19)
-      mongoid (~> 3.0.1)
-    moped (1.1.5)
-    multi_json (1.3.6)
-    origin (1.0.4)
+      mongoid (~> 3.0)
+    moped (1.4.3)
+    multi_json (1.6.1)
+    origin (1.0.11)
     pry (0.9.10)
       coderay (~> 1.0.5)
       method_source (~> 0.8)
@@ -47,7 +47,7 @@ GEM
     shoulda (2.11.3)
     slop (3.3.2)
     timecop (0.4.1)
-    tzinfo (0.3.33)
+    tzinfo (0.3.36)
     uuidtools (2.1.3)
     yard (0.6.8)
 

lib/mongoid_ext/tags.rb

@@ -11,10 +11,19 @@ def self.included(klass)
 
     module ClassMethods
       def tag_cloud(conditions = {}, limit = 30)
-        Mongoid.session(:default).command({
-          :eval => "function(collection, q,l) { return tag_cloud(collection, q,l); }",
-          :args => [self.collection_name, conditions, limit]
-        })['retval']
+        pipeline = []
+        if !conditions.blank?
+          match = {:$match => conditions }
+          pipeline << match
+        end
+
+        pipeline <<  {:$project => {:tags => 1}}
+        pipeline <<  {:$unwind => "$tags"}
+        pipeline <<  {:$group => {:_id => "$tags", :count => { :$sum => 1}}}
+        pipeline <<  {:$project => {:_id => 0, :name => '$_id', :count => 1}}
+        pipeline <<  {:$sort => {:count => -1}}
+        pipeline <<  {:$limit => limit}
+        self.collection.aggregate(pipeline)
       end
 
       # Model.find_with_tags("budget", "big").limit(4)
@@ -23,10 +32,25 @@ def find_with_tags(*tags)
       end
 
       def find_tags(regex, conditions = {}, limit = 30)
-        Mongoid.session(:default).command({
-          :eval => "function(collection, a,b,c) { return find_tags(collection, a,b,c); }",
-          :args => [self.collection_name, regex, conditions, limit]
-        })['retval']
+        pipeline = []
+        if regex.is_a? String
+          regex = /#{Regexp.escape(regex)}/
+        end
+        match = {:$match => {:tags => {:$in => [regex]}}}
+
+        if !conditions.blank?
+          match[:$match].merge! conditions
+        end
+        pipeline << match
+
+        pipeline <<  {:$project => {:tags => 1}}
+        pipeline <<  {:$unwind => "$tags"}
+        pipeline <<  {:$match => {:tags => regex}}
+        pipeline <<  {:$group => {:_id => "$tags", :count => { :$sum => 1}}}
+        pipeline <<  {:$project => {:_id => 0, :name => '$_id', :count => 1}}
+        pipeline <<  {:$sort => {:count => -1}}
+        pipeline <<  {:$limit => limit}
+        self.collection.aggregate(pipeline)
       end
     end
   end