From ac9c7680e564353b72fa52c887980ebc26fb9696 Mon Sep 17 00:00:00 2001
From: Ernie Miller <ernie@metautonomo.us>
Date: Mon, 12 Apr 2010 08:53:11 -0400
Subject: [PATCH] Allow ActiveRelation where condition hashes to access additional Arel predicates

Similar to 'table.column' => 'value', this patch enables 'column#method' => 'value'.

For instance, Article.where('title#matches' => 'Hello%') generates SQL like:

SELECT "articles".* FROM "articles" WHERE ("articles"."title" LIKE 'Hello%')
---
 .../active_record/relation/predicate_builder.rb    |   43 +++++++++++++++----
 activerecord/test/cases/relations_test.rb          |   11 +++++
 2 files changed, 45 insertions(+), 9 deletions(-)

diff --git a/activerecord/lib/active_record/relation/predicate_builder.rb b/activerecord/lib/active_record/relation/predicate_builder.rb
index d0efa21..5cba418 100644
--- a/activerecord/lib/active_record/relation/predicate_builder.rb
+++ b/activerecord/lib/active_record/relation/predicate_builder.rb
@@ -14,30 +14,55 @@ module ActiveRecord
           build_from_hash(value, table)
         else
           column = column.to_s
+          method = method_from_value(value)
 
           if column.include?('.')
             table_name, column = column.split('.', 2)
             table = Arel::Table.new(table_name, :engine => @engine)
           end
+          
+          if column.include?('#')
+            column, method = column.split('#', 2)
+          end
 
           unless attribute = table[column]
             raise StatementInvalid, "No attribute named `#{column}` exists for table `#{table.name}`"
           end
-
-          case value
-          when Array, ActiveRecord::Associations::AssociationCollection, ActiveRecord::Relation
-            values = value.to_a
-            attribute.in(values)
-          when Range
-            attribute.in(value)
-          else
-            attribute.eq(value)
+          
+          unless valid_comparison_method?(method)
+            raise StatementInvalid, "No comparison method named `#{method}` exists for column `#{column}`"
           end
+
+          attribute.send(method, *args_for_predicate(method.to_s, value))
         end
       end
 
       predicates.flatten
     end
+    
+    private
+    
+    def args_for_predicate(method, value)
+      value = [Array, ActiveRecord::Associations::AssociationCollection, ActiveRecord::Relation].include?(value.class) ? value.to_a : value
+      if method =~ /_(any|all)$/ && value.is_a?(Array)
+        value
+      else
+        [value]
+      end
+    end
+    
+    def method_from_value(value)
+      case value
+      when Array, Range, ActiveRecord::Associations::AssociationCollection, ActiveRecord::Relation
+        :in
+      else
+        :eq
+      end
+    end
+    
+    def valid_comparison_method?(method)
+      Arel::Attribute::Predications.instance_methods.map(&:to_s).include?(method.to_s)
+    end
 
   end
 end
diff --git a/activerecord/test/cases/relations_test.rb b/activerecord/test/cases/relations_test.rb
index 7b9e680..2791867 100644
--- a/activerecord/test/cases/relations_test.rb
+++ b/activerecord/test/cases/relations_test.rb
@@ -81,6 +81,17 @@ class RelationTest < ActiveRecord::TestCase
     assert_equal ['Mary'],  Author.where(["name = ?", 'Mary']).map(&:name)
     assert_equal ['Mary'],  Author.where("name = ?", 'Mary').map(&:name)
   end
+  
+  def test_finding_with_advanced_hash_conditions
+    assert_equal ["David"], Author.where('authors.name' => 'David').map(&:name)
+    assert_equal ["David"], Author.where('authors.name#matches' => 'D%').map(&:name)
+  end
+  
+  def test_finding_with_hash_conditions_checks_predicate_method
+    assert_raise ActiveRecord::StatementInvalid do
+      Author.where('authors.name#nosuchmethod' => 'David').map(&:name)
+    end
+  end
 
   def test_finding_with_order
     topics = Topic.order('id')
-- 
1.6.4.4