Passing aggregation options to the map/reduce ruby driver

lib/mongoid/taggable.rb

@@ -1,3 +1,4 @@
+# -*- coding: utf-8 -*-
 # Copyright (c) 2010 Wilker Lúcio <[email protected]>
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
@@ -17,7 +18,7 @@ module Mongoid::Taggable
 
   included do
     class_attribute :tags_field, :tags_separator, :tag_aggregation,
-      :instance_writer => false
+      :tag_aggregation_options, :instance_writer => false
 
     delegate :convert_string_tags_to_array, :aggregate_tags!, :aggregate_tags?,
       :to => 'self.class'
@@ -38,7 +39,8 @@ module ClassMethods
     #   class Article
     #     include Mongoid::Document
     #     include Mongoid::Taggable
-    #     taggable :keywords, :separator => ' ', :aggregation => true
+    #     taggable :keywords, :separator => ' ', :aggregation => true,
+    #       :aggregation_options => {}
     #   end
     #
     # @param [ Symbol ] field The name of the field for tags.
@@ -49,12 +51,15 @@ module ClassMethods
     # @option options [ true, false ] :aggregation Whether or not to
     #   aggregate counts of tags within the document collection using
     #   map/reduce; defaults to false
+    # @option options [ Hash ] :aggregation_options Options for the
+    #   map/reduce ruby-driver method; defaults to {}
     def taggable(*args)
       options = args.extract_options!
 
       self.tags_field = args.blank? ? :tags : args.shift
       self.tags_separator  = options.delete(:separator) { ',' }
       self.tag_aggregation = options.delete(:aggregation) { false }
+      self.tag_aggregation_options = options.delete(:aggregation_options) { {} }
 
       field tags_field, options.merge(:type => Array)
       index tags_field
@@ -110,7 +115,9 @@ def aggregate_tags!
         return count;
       }"
 
-      collection.master.map_reduce(map, reduce, :out => tags_aggregation_collection)
+      map_reduce_options = { :out => tags_aggregation_collection }.
+        merge(tag_aggregation_options)
+      collection.master.map_reduce(map, reduce, map_reduce_options)
     end
 
   private

spec/mongoid/taggable_spec.rb

@@ -1,3 +1,4 @@
+# -*- coding: utf-8 -*-
 # Copyright (c) 2010 Wilker Lúcio <[email protected]>
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
@@ -39,7 +40,16 @@ class Template
   include Mongoid::Taggable
   include Mongoid::Timestamps
 
-  taggable :aggregation => true
+  taggable :aggregation => true 
+end
+
+class Post
+  include Mongoid::Document
+  include Mongoid::Taggable
+
+  field :published, :type => Boolean
+
+  taggable :aggregation_options => {}
 end
 
 describe Mongoid::Taggable do
@@ -207,6 +217,26 @@ class Template
         Article.keywords_with_weight.should include(['tags', 2])
       end
     end
+
+    context "with aggregation options" do
+      let!(:posts) do 
+        [
+          Post.create!(:tags => "programming",         :published => false),
+          Post.create!(:tags => "sports,leisure",      :published => true),
+          Post.create!(:tags => "programming, sports", :published => true)
+        ]
+      end
+
+      it "counts aggregates with the specified options" do
+        Post.tag_aggregation_options = { :query => { :published => true } }
+        Post.aggregate_tags!
+        Post.tags_with_weight.should == [
+          ['leisure', 1],
+          ['programming', 1],
+          ['sports', 2],
+        ]
+      end
+    end
   end
 
   context "#self.tagged_with" do