Basic validation support [Rick Olson]

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

1 files changed, 125 insertions, 0 deletions

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
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