Add dynamic find_or_create_by_{attribute}! method.

activerecord/CHANGELOG.md

@@ -155,6 +155,8 @@
 
 ## Rails 3.2.3 (unreleased) ##
 
+*   Added find_or_create_by_{attribute}! dynamic method. *Andrew White*
+
 *   Whitelist all attribute assignment by default. Change the default for newly generated applications to whitelist all attribute assignment.  Also update the generated model classes so users are reminded of the importance of attr_accessible. *NZKoz*
 
 *   Update ActiveRecord::AttributeMethods#attribute_present? to return false for empty strings. *Jacobkg*

activerecord/lib/active_record/dynamic_finder_match.rb

@@ -7,7 +7,7 @@ module ActiveRecord
   class DynamicFinderMatch
     def self.match(method)
       method = method.to_s
-      klass = [FindBy, FindByBang, FindOrInitializeCreateBy].find do |_klass|
+      klass = klasses.find do |_klass|
         _klass.matches?(method)
       end
       klass.new(method) if klass
@@ -17,6 +17,10 @@ module ActiveRecord
       method =~ self::METHOD_PATTERN
     end
 
+    def self.klasses
+      [FindBy, FindByBang, FindOrInitializeCreateBy, FindOrCreateByBang]
+    end
+
     def initialize(method)
       @finder = :first
       @instantiator = nil
@@ -47,6 +51,14 @@ module ActiveRecord
       arguments.size >= @attribute_names.size
     end
 
+    def save_record?
+      @instantiator == :create
+    end
+
+    def save_method
+      bang? ? :save! : :save
+    end
+
     private
 
     def initialize_from_match_data(match_data)
@@ -81,4 +93,16 @@ module ActiveRecord
       arguments.size == 1 && arguments.first.is_a?(Hash) || super
     end
   end
+
+  class FindOrCreateByBang < DynamicFinderMatch
+    METHOD_PATTERN = /^find_or_create_by_([_a-zA-Z]\w*)\!$/
+
+    def initialize_from_match_data(match_data)
+      @instantiator = :create
+    end
+
+    def bang?
+      true
+    end
+  end
 end

activerecord/lib/active_record/relation/finder_methods.rb

@@ -290,7 +290,7 @@ module ActiveRecord
           r.assign_attributes(unprotected_attributes_for_create, :without_protection => true)
         end
         yield(record) if block_given?
-        record.save if match.instantiator == :create
+        record.send(match.save_method) if match.save_record?
       end
 
       record

activerecord/test/cases/dynamic_finder_match_test.rb

@@ -83,6 +83,14 @@ module ActiveRecord
       assert_equal :create, m.instantiator
     end
 
+    def test_find_or_create!
+      m = DynamicFinderMatch.match(:find_or_create_by_foo!)
+      assert_equal :first, m.finder
+      assert m.bang?, 'should be banging'
+      assert_equal %w{ foo }, m.attribute_names
+      assert_equal :create, m.instantiator
+    end
+
     def test_find_or_initialize
       m = DynamicFinderMatch.match(:find_or_initialize_by_foo)
       assert_equal :first, m.finder

activerecord/test/cases/finder_respond_to_test.rb

@@ -56,6 +56,16 @@ class FinderRespondToTest < ActiveRecord::TestCase
     assert_respond_to Topic, :find_or_create_by_title_and_author_name
   end
 
+  def test_should_respond_to_find_or_create_from_one_attribute_bang
+    ensure_topic_method_is_not_cached(:find_or_create_by_title!)
+    assert_respond_to Topic, :find_or_create_by_title!
+  end
+
+  def test_should_respond_to_find_or_create_from_two_attributes_bang
+    ensure_topic_method_is_not_cached(:find_or_create_by_title_and_author_name!)
+    assert_respond_to Topic, :find_or_create_by_title_and_author_name!
+  end
+
   def test_should_not_respond_to_find_by_one_missing_attribute
     assert !Topic.respond_to?(:find_by_undertitle)
   end

activerecord/test/cases/finder_test.rb

@@ -862,6 +862,28 @@ class FinderTest < ActiveRecord::TestCase
     assert another.persisted?
   end
 
+  def test_find_or_create_from_one_attribute_bang
+    number_of_companies = Company.count
+    assert_raises(ActiveRecord::RecordInvalid) { Company.find_or_create_by_name!("") }
+    assert_equal number_of_companies, Company.count
+    sig38 = Company.find_or_create_by_name!("38signals")
+    assert_equal number_of_companies + 1, Company.count
+    assert_equal sig38, Company.find_or_create_by_name!("38signals")
+    assert sig38.persisted?
+  end
+
+  def test_find_or_create_from_two_attributes_bang
+    number_of_companies = Company.count
+    assert_raises(ActiveRecord::RecordInvalid) { Company.find_or_create_by_name_and_firm_id!("", 17) }
+    assert_equal number_of_companies, Company.count
+    sig38 = Company.find_or_create_by_name_and_firm_id!("38signals", 17)
+    assert_equal number_of_companies + 1, Company.count
+    assert_equal sig38, Company.find_or_create_by_name_and_firm_id!("38signals", 17)
+    assert sig38.persisted?
+    assert_equal "38signals", sig38.name
+    assert_equal 17, sig38.firm_id
+  end
+
   def test_find_or_create_from_two_attributes_with_one_being_an_aggregate
     number_of_customers = Customer.count
     created_customer = Customer.find_or_create_by_balance_and_name(Money.new(123), "Elizabeth")

activerecord/test/cases/relations_test.rb

@@ -462,6 +462,18 @@ class RelationTest < ActiveRecord::TestCase
     assert_equal authors(:david), authors.find_or_create_by_name(:name => 'David')
   end
 
+  def test_dynamic_find_or_create_by_attributes_bang
+    authors = Author.scoped
+
+    assert_raises(ActiveRecord::RecordInvalid) { authors.find_or_create_by_name!('') }
+
+    lifo = authors.find_or_create_by_name!('Lifo')
+    assert_equal "Lifo", lifo.name
+    assert lifo.persisted?
+
+    assert_equal authors(:david), authors.find_or_create_by_name!(:name => 'David')
+  end
+
   def test_find_id
     authors = Author.scoped