Added validations to ActiveResource. Added a smoke test to see if we can add a...

Added validations to ActiveResource. Added a smoke test to see if we can add a validation and use it, and add a validates callback and use it.
Signed-off-by: NJoshua Peek <josh@joshpeek.com>

activeresource/lib/active_resource/validations.rb

@@ -8,8 +8,10 @@ class ResourceInvalid < ClientError  #:nodoc:
   # to determine whether the object in a valid state to be saved. See usage example in Validations.  
   class Errors < ActiveModel::Errors
     # Grabs errors from an array of messages (like ActiveRecord::Validations)
-    def from_array(messages)
-      clear
+    # The second parameter directs the errors cache to be cleared (default)
+    # or not (by passing true)
+    def from_array(messages, save_cache = false)
+      clear unless save_cache
       humanized_attributes = @base.attributes.keys.inject({}) { |h, attr_name| h.update(attr_name.humanize => attr_name) }
       messages.each do |message|
         attr_message = humanized_attributes.keys.detect do |attr_name|
@@ -22,16 +24,16 @@ def from_array(messages)
       end
     end
 
-    # Grabs errors from the json response.
-    def from_json(json)
+    # Grabs errors from a json response.
+    def from_json(json, save_cache = false)
       array = ActiveSupport::JSON.decode(json)['errors'] rescue []
-      from_array array
+      from_array array, save_cache
     end
 
-    # Grabs errors from the XML response.
-    def from_xml(xml)
+    # Grabs errors from an XML response.
+    def from_xml(xml, save_cache = false)
       array = Array.wrap(Hash.from_xml(xml)['errors']['error']) rescue []
-      from_array array
+      from_array array, save_cache
     end
   end
   
@@ -57,26 +59,55 @@ def from_xml(xml)
   #
   module Validations
     extend ActiveSupport::Concern
+    include ActiveModel::Validations
+    extend ActiveModel::Validations::ClassMethods
 
     included do
       alias_method_chain :save, :validation
     end
 
     # Validate a resource and save (POST) it to the remote web service.
-    def save_with_validation
-      save_without_validation
-      true
+    # If any local validations fail - the save (POST) will not be attempted.
+    def save_with_validation(perform_validation = true)
+      # clear the remote validations so they don't interfere with the local
+      # ones. Otherwise we get an endless loop and can never change the
+      # fields so as to make the resource valid
+      @remote_errors = nil
+      if perform_validation && valid? || !perform_validation
+        save_without_validation
+        true
+      else
+        false
+      end
     rescue ResourceInvalid => error
-      case error.response['Content-Type']
+      # cache the remote errors because every call to <tt>valid?</tt> clears
+      # all errors. We must keep a copy to add these back after local
+      # validations
+      @remote_errors = error
+      load_remote_errors(@remote_errors, true)
+      false
+    end
+
+
+    # Loads the set of remote errors into the object's Errors based on the
+    # content-type of the error-block received
+    def load_remote_errors(remote_errors, save_cache = false ) #:nodoc:
+      case remote_errors.response['Content-Type']
       when 'application/xml'
-        errors.from_xml(error.response.body)
+        errors.from_xml(remote_errors.response.body, save_cache)
       when 'application/json'
-        errors.from_json(error.response.body)
+        errors.from_json(remote_errors.response.body, save_cache)
       end
-      false
     end
 
     # Checks for errors on an object (i.e., is resource.errors empty?).
+    #
+    # Runs all the specified local validations and returns true if no errors
+    # were added, otherwise false.
+    # Runs local validations (eg those on your Active Resource model), and
+    # also any errors returned from the remote system the last time we
+    # saved.
+    # Remote errors can only be cleared by trying to re-save the resource.
     # 
     # ==== Examples
     #   my_person = Person.create(params[:person])
@@ -86,7 +117,10 @@ def save_with_validation
     #   my_person.errors.add('login', 'can not be empty') if my_person.login == ''
     #   my_person.valid?
     #   # => false
+    #
     def valid?
+      super
+      load_remote_errors(@remote_errors, true) if defined?(@remote_errors) && @remote_errors.present?
       errors.empty?
     end
 

activeresource/test/fixtures/project.rb

+# used to test validations
+class Project < ActiveResource::Base
+  self.site = "http://37s.sunrise.i:3000"
+
+  validates_presence_of :name
+  validate :description_greater_than_three_letters
+
+  # to test the validate *callback* works
+  def description_greater_than_three_letters
+    errors.add :description, 'must be greater than three letters long' if description.length < 3 unless description.blank?
+  end
+
+
+  # stop-gap accessor to default this attribute to nil
+  # Otherwise the validations fail saying that the method does not exist.
+  # In future, method_missing will be updated to not explode on a known
+  # attribute.
+  def name
+    attributes['name'] || nil
+  end
+  def description
+    attributes['description'] || nil
+  end
+end
+

activeresource/test/validations_test.rb

+require 'abstract_unit'
+require "fixtures/project"
+
+# The validations are tested thoroughly under ActiveModel::Validations
+# This test case simply makes sur that they are all accessible by
+# Active Resource objects.
+class ValidationsTest < ActiveModel::TestCase
+  VALID_PROJECT_HASH = { :name => "My Project", :description => "A project" }
+  def setup
+    @my_proj = VALID_PROJECT_HASH.to_xml(:root => "person")
+    ActiveResource::HttpMock.respond_to do |mock|
+      mock.post "/projects.xml", {}, @my_proj, 201, 'Location' => '/projects/5.xml'
+    end
+  end
+
+  def test_validates_presence_of
+    p = new_project(:name => nil)
+    assert !p.valid?, "should not be a valid record without name"
+    assert !p.save, "should not have saved an invalid record"
+    assert_equal ["can't be blank"], p.errors[:name], "should have an error on name"
+
+    p.name = "something"
+
+    assert p.save, "should have saved after fixing the validation, but had: #{p.errors.inspect}"
+  end
+
+  def test_validate_callback
+    # we have a callback ensuring the description is longer thn three letters
+    p = new_project(:description => 'a')
+    assert !p.valid?, "should not be a valid record when it fails a validation callback"
+    assert !p.save, "should not have saved an invalid record"
+    assert_equal ["must be greater than three letters long"], p.errors[:description], "should be an error on description"
+
+    # should now allow this description
+    p.description = 'abcd'
+    assert p.save, "should have saved after fixing the validation, but had: #{p.errors.inspect}"
+  end
+
+  protected
+
+  # quickie helper to create a new project with all the required
+  # attributes.
+  # Pass in any params you specifically want to override
+  def new_project(opts = {})
+    Project.new(VALID_PROJECT_HASH.merge(opts))
+  end
+
+end
+