Started added a validation mixin

Usage:
  class Invoice < CouchRest::ExtendedDocument
    include CouchRest::Validation

    property :client_name
    property :employee_name
    property :location

    # Validation
    validates_present :client_name, :employee_name
    validates_present :location, :message => "Hey stupid!, you forgot the location"

  end

lib/couchrest/validation/validators/formats/email.rb

@@ -0,0 +1,66 @@
+# encoding: binary
+
+# Extracted from dm-validations 0.9.10
+#
+# Copyright (c) 2007 Guy van den Berg
+# 
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+# 
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+# 
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+module CouchRest
+  module Validation
+    module Format
+      module Email
+
+        def self.included(base)
+          CouchRest::Validation::FormatValidator::FORMATS.merge!(
+            :email_address => [ EmailAddress, lambda { |field, value| '%s is not a valid email address'.t(value) }]
+          )
+        end
+
+        # RFC2822 (No attribution reference available)
+        EmailAddress = begin
+            alpha = "a-zA-Z"
+            digit = "0-9"
+            atext = "[#{alpha}#{digit}\!\#\$\%\&\'\*+\/\=\?\^\_\`\{\|\}\~\-]"
+            dot_atom_text = "#{atext}+([.]#{atext}*)*"
+            dot_atom = "#{dot_atom_text}"
+            qtext = '[^\\x0d\\x22\\x5c\\x80-\\xff]'
+            text = "[\\x01-\\x09\\x11\\x12\\x14-\\x7f]"
+            quoted_pair = "(\\x5c#{text})"
+            qcontent = "(?:#{qtext}|#{quoted_pair})"
+            quoted_string = "[\"]#{qcontent}+[\"]"
+            atom = "#{atext}+"
+            word = "(?:#{atom}|#{quoted_string})"
+            obs_local_part = "#{word}([.]#{word})*"
+            local_part = "(?:#{dot_atom}|#{quoted_string}|#{obs_local_part})"
+            no_ws_ctl = "\\x01-\\x08\\x11\\x12\\x14-\\x1f\\x7f"
+            dtext = "[#{no_ws_ctl}\\x21-\\x5a\\x5e-\\x7e]"
+            dcontent = "(?:#{dtext}|#{quoted_pair})"
+            domain_literal = "\\[#{dcontent}+\\]"
+            obs_domain = "#{atom}([.]#{atom})*"
+            domain = "(?:#{dot_atom}|#{domain_literal}|#{obs_domain})"
+            addr_spec = "#{local_part}\@#{domain}"
+            pattern = /^#{addr_spec}$/
+        end
+
+      end # module Email
+    end # module Format
+  end # module Validation
+end # module CouchRest

lib/couchrest/validation/validators/formats/url.rb

@@ -0,0 +1,43 @@
+# Extracted from dm-validations 0.9.10
+#
+# Copyright (c) 2007 Guy van den Berg
+# 
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+# 
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+# 
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+module CouchRest
+  module Validation
+    module Format
+      module Url
+
+        def self.included(base)
+          CouchRest::Validation::FormatValidator::FORMATS.merge!(
+            :url => [ Url, lambda { |field, value| '%s is not a valid URL'.t(value) }]
+          )
+        end
+
+        Url = begin
+          # Regex from http://www.igvita.com/2006/09/07/validating-url-in-ruby-on-rails/
+          /(^$)|(^(http|https):\/\/[a-z0-9]+([\-\.]{1}[a-z0-9]+)*\.[a-z]{2,5}(([0-9]{1,5})?\/.*)?$)/ix
+        end
+
+      end # module Url
+    end # module Format
+  end # module Validation
+end # module CouchRest