Basic validation support [Rick Olson]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@5068 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

6 files changed, 184 insertions, 3 deletions

diff --git a/activeresource/CHANGELOG b/activeresource/CHANGELOG
index 2133824488..ef3f3f6a17 100644
--- a/activeresource/CHANGELOG
+++ b/activeresource/CHANGELOG
@@ -1,5 +1,11 @@
 *SVN*
 
+* Basic validation support [Rick Olson]
+
+  Parses the xml response of ActiveRecord::Errors#to_xml with a similar interface to ActiveRecord::Errors.  
+  
+    render :xml => @person.errors.to_xml, :status => '400 Validation Error'
+
 * Deep hashes are converted into collections of resources.  [Jeremy Kemper]
     Person.new :name => 'Bob',
                :address => { :id => 1, :city => 'Portland' },
diff --git a/activeresource/lib/active_resource.rb b/activeresource/lib/active_resource.rb
index 529675a59c..89fd6f7722 100644
--- a/activeresource/lib/active_resource.rb
+++ b/activeresource/lib/active_resource.rb
@@ -35,4 +35,11 @@ unless defined?(ActiveSupport)
 end
 
 require 'active_resource/base'
-require 'active_resource/struct'
\ No newline at end of file
+require 'active_resource/struct'
+require 'active_resource/validations'
+
+module ActiveResource
+  Base.class_eval do
+    include Validations
+  end
+end
\ No newline at end of file
diff --git a/activeresource/lib/active_resource/connection.rb b/activeresource/lib/active_resource/connection.rb
index 22689444b2..132e861292 100644
--- a/activeresource/lib/active_resource/connection.rb
+++ b/activeresource/lib/active_resource/connection.rb
@@ -71,7 +71,9 @@ module ActiveResource
             response
           when 404
             raise(ResourceNotFound.new(response))
-          when 400...500
+          when 400
+            raise(ResourceInvalid.new(response))
+          when 401...500
             raise(ClientError.new(response))
           when 500...600
             raise(ServerError.new(response))
diff --git a/activeresource/lib/active_resource/validations.rb b/activeresource/lib/active_resource/validations.rb
new file mode 100644
index 0000000000..8414e93293
--- /dev/null
+++ b/activeresource/lib/active_resource/validations.rb
@@ -0,0 +1,125 @@
+module ActiveResource
+  class ResourceInvalid < ClientError
+  end
+
+  class Errors
+    include Enumerable
+    attr_reader :errors
+
+    delegate :empty?, :to => :errors
+    
+    def initialize(base) # :nodoc:
+      @base, @errors = base, {}
+    end
+
+    def add_to_base(msg)
+      add(:base, msg)
+    end
+
+    def add(attribute, msg)
+      @errors[attribute.to_s] = [] if @errors[attribute.to_s].nil?
+      @errors[attribute.to_s] << msg
+    end
+
+    # Returns true if the specified +attribute+ has errors associated with it.
+    def invalid?(attribute)
+      !@errors[attribute.to_s].nil?
+    end
+
+    # * Returns nil, if no errors are associated with the specified +attribute+.
+    # * Returns the error message, if one error is associated with the specified +attribute+.
+    # * Returns an array of error messages, if more than one error is associated with the specified +attribute+.
+    def on(attribute)
+      errors = @errors[attribute.to_s]
+      return nil if errors.nil?
+      errors.size == 1 ? errors.first : errors
+    end
+    
+    alias :[] :on
+
+    # Returns errors assigned to base object through add_to_base according to the normal rules of on(attribute).
+    def on_base
+      on(:base)
+    end
+
+    # Yields each attribute and associated message per error added.
+    def each
+      @errors.each_key { |attr| @errors[attr].each { |msg| yield attr, msg } }
+    end
+
+    # Yields each full error message added. So Person.errors.add("first_name", "can't be empty") will be returned
+    # through iteration as "First name can't be empty".
+    def each_full
+      full_messages.each { |msg| yield msg }
+    end
+
+    # Returns all the full error messages in an array.
+    def full_messages
+      full_messages = []
+
+      @errors.each_key do |attr|
+        @errors[attr].each do |msg|
+          next if msg.nil?
+
+          if attr == "base"
+            full_messages << msg
+          else
+            full_messages << [attr.humanize, msg].join(' ')
+          end
+        end
+      end
+      full_messages
+    end
+
+    def clear
+      @errors = {}
+    end
+
+    # Returns the total number of errors added. Two errors added to the same attribute will be counted as such
+    # with this as well.
+    def size
+      @errors.values.inject(0) { |error_count, attribute| error_count + attribute.size }
+    end
+
+    alias_method :count, :size
+    alias_method :length, :size
+    
+    def from_xml(xml)
+      clear
+      humanized_attributes = @base.attributes.keys.inject({}) { |h, attr_name| h.update(attr_name.humanize => attr_name) }
+      messages = Hash.create_from_xml(xml)['errors']['error'] rescue []
+      messages.each do |message|
+        attr_message = humanized_attributes.keys.detect do |attr_name|
+          if message[0, attr_name.size + 1] == "#{attr_name} "
+            add humanized_attributes[attr_name], message[(attr_name.size + 1)..-1]
+          end
+        end
+        
+        add_to_base message if attr_message.nil?
+      end
+    end
+  end
+  
+  module Validations
+    def self.included(base) # :nodoc:
+      base.class_eval do
+        alias_method_chain :save, :validation
+      end
+    end
+
+    def save_with_validation
+      save_without_validation
+    rescue ResourceInvalid
+      errors.from_xml($!.response.body)
+    end
+
+    def valid?
+      errors.empty?
+    end
+
+    # Returns the Errors object that holds all information about attribute error messages.
+    def errors
+      @errors ||= Errors.new(self)
+    end
+  end
+end
\ No newline at end of file
diff --git a/activeresource/test/base_errors_test.rb b/activeresource/test/base_errors_test.rb
new file mode 100644
index 0000000000..25a368535f
--- /dev/null
+++ b/activeresource/test/base_errors_test.rb
@@ -0,0 +1,38 @@
+require "#{File.dirname(__FILE__)}/abstract_unit"
+require "fixtures/person"
+
+class BaseErrorsTest < Test::Unit::TestCase
+  def setup
+    ActiveResource::HttpMock.respond_to do |mock|
+      mock.post "/people", "<?xml version=\"1.0\" encoding=\"UTF-8\"?><errors><error>Age can't be blank</error><error>Name can't be blank</error><error>Name must start with a letter</error><error>Person quota full for today.</error></errors>", 400
+    end
+    @exception = nil
+    @person    = Person.new(:name => '', :age => '')
+    @person.save
+  rescue ActiveResource::ResourceInvalid
+    @exception = $!
+  end
+  
+  def test_should_mark_as_invalid
+    assert !@person.valid?
+  end
+  
+  def test_should_parse_xml_errors
+    assert_kind_of ActiveResource::Errors, @person.errors
+    assert_equal 4, @person.errors.size
+  end
+
+  def test_should_parse_errors_to_individual_attributes
+    assert_equal "can't be blank", @person.errors.on(:age)
+    assert_equal ["can't be blank", "must start with a letter"], @person.errors[:name]
+    assert_equal "Person quota full for today.", @person.errors.on_base
+  end
+
+  def test_should_format_full_errors
+    full = @person.errors.full_messages
+    assert full.include?("Age can't be blank")
+    assert full.include?("Name can't be blank")
+    assert full.include?("Name must start with a letter")
+    assert full.include?("Person quota full for today.")
+  end
+end
\ No newline at end of file
diff --git a/activeresource/test/connection_test.rb b/activeresource/test/connection_test.rb
index 4790c30bed..d72c1c612d 100644
--- a/activeresource/test/connection_test.rb
+++ b/activeresource/test/connection_test.rb
@@ -17,8 +17,11 @@ class ConnectionTest < Test::Unit::TestCase
     # 404 is a missing resource.
     assert_response_raises ActiveResource::ResourceNotFound, 404
 
+    # 400 is a validation error
+    assert_response_raises ActiveResource::ResourceInvalid, 400
+
     # 4xx are client errors.
-    [400, 499].each do |code|
+    [401, 499].each do |code|
       assert_response_raises ActiveResource::ClientError, code
     end