Added the :if option to all validations that can either use a block or a...

Added the :if option to all validations that can either use a block or a method pointer to determine whether the validation should be run or not. #1324 [Duane Johnson/jhosteny]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@1340 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/CHANGELOG

 *SVN*
 
+* Added the :if option to all validations that can either use a block or a method pointer to determine whether the validation should be run or not. #1324 [Duane Johnson/jhosteny]. Examples:
+
+  Conditional validations such as the following are made possible:
+    validates_numericality_of :income, :if => :employed?
+
+  Conditional validations can also solve the salted login generator problem:
+    validates_confirmation_of :password, :if => :new_password?
+  
+  Using blocks:
+    validates_presence_of :username, :if => Proc.new { |user| user.signup_step > 1 }
+
 * Fixed use of construct_finder_sql when using :join #1288 [dwlt@dwlt.net]
 
 * Fixed that :delete_sql in has_and_belongs_to_many associations couldn't access record properties #1299 [Rick Olson]

activerecord/lib/active_record/validations.rb

@@ -227,6 +227,29 @@ def validate_on_update(*methods, &block)
         write_inheritable_set(:validate_on_update, methods)
       end
 
+      def condition_block?(condition)
+        condition.respond_to?("call") && (condition.arity == 1 || condition.arity == -1)
+      end
+
+      # Determine from the given condition (whether a block, procedure, method or string)
+      # whether or not to validate the record.  See #validates_each.
+      def evaluate_condition(condition, record)
+        case condition
+          when Symbol: record.send(condition)
+          when String: eval(condition, binding)
+          else
+            if condition_block?(condition)
+              condition.call(record)
+            else
+              raise(
+                ActiveRecordError,
+                "Validations need to be either a symbol, string (to be eval'ed), proc/method, or " +
+                "class implementing a static validation method"
+              )
+            end
+          end
+      end
+
       # Validates each attribute against a block.
       #
       #   class Person < ActiveRecord::Base
@@ -238,12 +261,17 @@ def validate_on_update(*methods, &block)
       # Options:
       # * <tt>on</tt> - Specifies when this validation is active (default is :save, other options :create, :update)
       # * <tt>allow_nil</tt> - Skip validation if attribute is nil.
+      # * <tt>if</tt> - Specifies a method, proc or string to call to determine if the validation should
+      # occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }).  The
+      # method, proc or string should return or evaluate to a true or false value.
       def validates_each(*attrs)
         options = attrs.last.is_a?(Hash) ? attrs.pop.symbolize_keys : {}
         attrs = attrs.flatten
 
         # Declare the validation.
         send(validation_method(options[:on] || :save)) do |record|
+          # Don't validate when there is an :if condition and that condition is false
+          unless options[:if] && !evaluate_condition(options[:if], record)
             attrs.each do |attr|
               value = record.send(attr)
               next if value.nil? && options[:allow_nil]
@@ -251,6 +279,7 @@ def validates_each(*attrs)
             end
           end
         end
+      end
 
       # Encapsulates the pattern of wanting to validate a password or email address field with a confirmation. Example:
       #
@@ -271,6 +300,9 @@ def validates_each(*attrs)
       # Configuration options:
       # * <tt>message</tt> - A custom error message (default is: "doesn't match confirmation")
       # * <tt>on</tt> - Specifies when this validation is active (default is :save, other options :create, :update)
+      # * <tt>if</tt> - Specifies a method, proc or string to call to determine if the validation should
+      # occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }).  The
+      # method, proc or string should return or evaluate to a true or false value.
       def validates_confirmation_of(*attr_names)
         configuration = { :message => ActiveRecord::Errors.default_error_messages[:confirmation], :on => :save }
         configuration.update(attr_names.pop) if attr_names.last.is_a?(Hash)
@@ -297,6 +329,9 @@ def validates_confirmation_of(*attr_names)
       # * <tt>on</tt> - Specifies when this validation is active (default is :save, other options :create, :update)
       # * <tt>accept</tt> - Specifies value that is considered accepted.  The default value is a string "1", which
       # makes it easy to relate to an HTML checkbox.
+      # * <tt>if</tt> - Specifies a method, proc or string to call to determine if the validation should
+      # occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }).  The
+      # method, proc or string should return or evaluate to a true or false value.
       def validates_acceptance_of(*attr_names)
         configuration = { :message => ActiveRecord::Errors.default_error_messages[:accepted], :on => :save, :allow_nil => true, :accept => "1" }
         configuration.update(attr_names.pop) if attr_names.last.is_a?(Hash)
@@ -313,6 +348,9 @@ def validates_acceptance_of(*attr_names)
       # Configuration options:
       # * <tt>message</tt> - A custom error message (default is: "has already been taken")
       # * <tt>on</tt> - Specifies when this validation is active (default is :save, other options :create, :update)
+      # * <tt>if</tt> - Specifies a method, proc or string to call to determine if the validation should
+      # occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }).  The
+      # method, proc or string should return or evaluate to a true or false value.
       def validates_presence_of(*attr_names)
         configuration = { :message => ActiveRecord::Errors.default_error_messages[:empty], :on => :save }
         configuration.update(attr_names.pop) if attr_names.last.is_a?(Hash)
@@ -321,10 +359,12 @@ def validates_presence_of(*attr_names)
         # while errors.add_on_empty can	
         attr_names.each do |attr_name|
           send(validation_method(configuration[:on])) do |record|
+            unless configuration[:if] and not evaluate_condition(configuration[:if], record)
               record.errors.add_on_empty(attr_name,configuration[:message])
             end
           end
         end
+      end
 
       # Validates that the specified attribute matches the length restrictions supplied. Only one option can be used at a time:
       #
@@ -350,6 +390,9 @@ def validates_presence_of(*attr_names)
       # * <tt>wrong_length</tt> - The error message if using the :is method and the attribute is the wrong size (default is: "is the wrong length (should be %d characters)")
       # * <tt>message</tt> - The error message to use for a :minimum, :maximum, or :is violation.  An alias of the appropriate too_long/too_short/wrong_length message
       # * <tt>on</tt> - Specifies when this validation is active (default is :save, other options :create, :update)
+      # * <tt>if</tt> - Specifies a method, proc or string to call to determine if the validation should
+      # occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }).  The
+      # method, proc or string should return or evaluate to a true or false value.
       def validates_length_of(*attrs)
         # Merge given options with defaults.
         options = DEFAULT_SIZE_VALIDATION_OPTIONS.dup
@@ -408,6 +451,9 @@ def validates_length_of(*attrs)
       # Configuration options:
       # * <tt>message</tt> - Specifies a custom error message (default is: "has already been taken")
       # * <tt>scope</tt> - Ensures that the uniqueness is restricted to a condition of "scope = record.scope"
+      # * <tt>if</tt> - Specifies a method, proc or string to call to determine if the validation should
+      # occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }).  The
+      # method, proc or string should return or evaluate to a true or false value.
       def validates_uniqueness_of(*attr_names)
         configuration = { :message => ActiveRecord::Errors.default_error_messages[:taken] }
         configuration.update(attr_names.pop) if attr_names.last.is_a?(Hash)
@@ -436,6 +482,9 @@ def validates_uniqueness_of(*attr_names)
       # * <tt>message</tt> - A custom error message (default is: "is invalid")
       # * <tt>with</tt> - The regular expression used to validate the format with (note: must be supplied!)
       # * <tt>on</tt> Specifies when this validation is active (default is :save, other options :create, :update)
+      # * <tt>if</tt> - Specifies a method, proc or string to call to determine if the validation should
+      # occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }).  The
+      # method, proc or string should return or evaluate to a true or false value.
       def validates_format_of(*attr_names)
         configuration = { :message => ActiveRecord::Errors.default_error_messages[:invalid], :on => :save, :with => nil }
         configuration.update(attr_names.pop) if attr_names.last.is_a?(Hash)
@@ -458,6 +507,9 @@ def validates_format_of(*attr_names)
       # * <tt>in</tt> - An enumerable object of available items
       # * <tt>message</tt> - Specifies a customer error message (default is: "is not included in the list")
       # * <tt>allow_nil</tt> - If set to true, skips this validation if the attribute is null (default is: false)
+      # * <tt>if</tt> - Specifies a method, proc or string to call to determine if the validation should
+      # occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }).  The
+      # method, proc or string should return or evaluate to a true or false value.
       def validates_inclusion_of(*attr_names)
         configuration = { :message => ActiveRecord::Errors.default_error_messages[:inclusion], :on => :save }
         configuration.update(attr_names.pop) if attr_names.last.is_a?(Hash)
@@ -482,6 +534,9 @@ def validates_inclusion_of(*attr_names)
       # * <tt>in</tt> - An enumerable object of items that the value shouldn't be part of
       # * <tt>message</tt> - Specifies a customer error message (default is: "is reserved")
       # * <tt>allow_nil</tt> - If set to true, skips this validation if the attribute is null (default is: false)
+      # * <tt>if</tt> - Specifies a method, proc or string to call to determine if the validation should
+      # occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }).  The
+      # method, proc or string should return or evaluate to a true or false value.
       def validates_exclusion_of(*attr_names)
         configuration = { :message => ActiveRecord::Errors.default_error_messages[:exclusion], :on => :save }
         configuration.update(attr_names.pop) if attr_names.last.is_a?(Hash)
@@ -516,6 +571,9 @@ def validates_exclusion_of(*attr_names)
       #
       # Configuration options:
       # * <tt>on</tt> Specifies when this validation is active (default is :save, other options :create, :update)
+      # * <tt>if</tt> - Specifies a method, proc or string to call to determine if the validation should
+      # occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }).  The
+      # method, proc or string should return or evaluate to a true or false value.
       def validates_associated(*attr_names)
         configuration = { :message => ActiveRecord::Errors.default_error_messages[:invalid], :on => :save }
         configuration.update(attr_names.pop) if attr_names.last.is_a?(Hash)
@@ -539,6 +597,9 @@ def validates_associated(*attr_names)
       # * <tt>on</tt> Specifies when this validation is active (default is :save, other options :create, :update)
       # * <tt>only_integer</tt> Specifies whether the value has to be an integer, e.g. an integral value (default is false)
       # * <tt>allow_nil</tt> Skip validation if attribute is nil (default is false). Notice that for fixnum and float columsn empty strings are converted to nil
+      # * <tt>if</tt> - Specifies a method, proc or string to call to determine if the validation should
+      # occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }).  The
+      # method, proc or string should return or evaluate to a true or false value.
       def validates_numericality_of(*attr_names)
         configuration = { :message => ActiveRecord::Errors.default_error_messages[:not_a_number], :on => :save,
                            :only_integer => false, :allow_nil => false }

activerecord/test/validations_test.rb

@@ -3,6 +3,17 @@
 require 'fixtures/reply'
 require 'fixtures/developer'
 
+# The following methods in Topic are used in test_conditional_validation_*
+class Topic
+  def condition_is_true
+    return true
+  end
+
+  def condition_is_true_but_its_not
+    return false
+  end
+end
+
 class ValidationsTest < Test::Unit::TestCase
   fixtures :topics, :developers
 
@@ -707,4 +718,56 @@ def test_validates_numericality_of_int
     end
   end
 
+  def test_conditional_validation_using_method_true
+    # When the method returns true
+    Topic.validates_length_of( :title, :maximum=>5, :too_long=>"hoo %d", :if => :condition_is_true )
+    t = Topic.create("title" => "uhohuhoh", "content" => "whatever")
+    assert !t.valid?
+    assert t.errors.on(:title)
+    assert_equal "hoo 5", t.errors["title"]
+  end
+
+  def test_conditional_validation_using_method_false
+    # When the method returns false
+    Topic.validates_length_of( :title, :maximum=>5, :too_long=>"hoo %d", :if => :condition_is_true_but_its_not )
+    t = Topic.create("title" => "uhohuhoh", "content" => "whatever")
+    assert t.valid?
+    assert !t.errors.on(:title)      
+  end
+
+  def test_conditional_validation_using_string_true
+    # When the evaluated string returns true
+    Topic.validates_length_of( :title, :maximum=>5, :too_long=>"hoo %d", :if => "a = 1; a == 1" )
+    t = Topic.create("title" => "uhohuhoh", "content" => "whatever")
+    assert !t.valid?
+    assert t.errors.on(:title)
+    assert_equal "hoo 5", t.errors["title"]
+  end
+
+  def test_conditional_validation_using_string_false
+    # When the evaluated string returns false
+    Topic.validates_length_of( :title, :maximum=>5, :too_long=>"hoo %d", :if => "false")
+    t = Topic.create("title" => "uhohuhoh", "content" => "whatever")
+    assert t.valid?
+    assert !t.errors.on(:title)
+  end
+
+  def test_conditional_validation_using_block_true
+    # When the block returns true
+    Topic.validates_length_of( :title, :maximum=>5, :too_long=>"hoo %d",
+      :if => Proc.new { |r| r.content.size > 4 } )
+    t = Topic.create("title" => "uhohuhoh", "content" => "whatever")
+    assert !t.valid?
+    assert t.errors.on(:title)
+    assert_equal "hoo 5", t.errors["title"]
+  end
+
+  def test_conditional_validation_using_block_false
+    # When the block returns false
+    Topic.validates_length_of( :title, :maximum=>5, :too_long=>"hoo %d",
+      :if => Proc.new { |r| r.title != "uhohuhoh"} )
+    t = Topic.create("title" => "uhohuhoh", "content" => "whatever")
+    assert t.valid?
+    assert !t.errors.on(:title)
+  end
 end