Add optional plist serialization format to Rabl

Details
* Fixes #90 (nesquena/rabl issues tracker)
* Plist: http://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/PropertyLists/Introduction/Introduction.htmlrubgems
* Defaults to using the Ruby plist gem: http://rubygems.org/gems/plist
* Adds Rabl configuration option include_plist_root which has same semantics as include_json_root.
* Adds Rabl configuration option plist_engine which has similar semantics as json_engine.
* Adds tests
* Updated README.md to reflect the plist changes.

README.md

@@ -102,9 +102,11 @@ Rabl.configure do |config|
   # config.json_engine = nil # Any multi\_json engines
   # config.msgpack_engine = nil # Defaults to ::MessagePack
   # config.bson_engine = nil # Defaults to ::BSON
+  # config.plist_engine = nil # Defaults to ::Plist::Emit
   # config.include_json_root = true
   # config.include_msgpack_root = true
   # config.include_bson_root = true
+  # config.include_plist_root = true
   # config.include_xml_root  = false
   # config.enable_json_callbacks = false
   # config.xml_options = { :dasherize  => true, :skip_types => false }
@@ -191,6 +193,32 @@ end
 *NOTE*: Attempting to render the bson format without either including the bson gem or
 setting a `bson_engine` will cause an exception to be raised.
 
+### Plist ###
+
+Rabl also includes optional support for [Plist](http://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/PropertyLists/Introduction/Introduction.html]) serialization format using the [plist gem](http://plist.rubyforge.org/).
+To enable, include the plist gem in your project's Gemfile. Then use Rabl as normal with the `plist` format (akin to other formats).
+
+```ruby
+# Gemfile
+gem 'plist'
+```
+
+There is also an option for a custom Plist implementation by setting the Rabl `plist_engine` configuration attribute.
+
+```ruby
+class CustomEncodeEngine
+  def self.dump string
+    # Custom Encoding by your own engine.
+  end
+end
+
+Rabl.configure do |config|
+  config.plist_engine = CustomEncodeEngine
+end
+```
+
+*NOTE*: Attempting to render the plist format without either including the plist gem or setting a `plist_engine` will cause an exception to be raised.
+
 ## Usage ##
 
 ### Object Assignment ###
@@ -482,6 +510,7 @@ Thanks to [Miso](http://gomiso.com) for allowing me to create this for our appli
 * [Matthew Schulkind](https://github.com/mschulkind) - Cleanup of configuration and tests
 * [Luke van der Hoeven](https://github.com/plukevdh) - Support non-ORM objects in templates
 * [Andrey Voronkov](https://github.com/Antiarchitect) - Added BSON format support
+* [Alli Witheford](https://github.com/alzeih) - Added Plist format support
 
 and many more contributors listed in the [CHANGELOG](https://github.com/nesquena/rabl/blob/master/CHANGELOG.md).
 

lib/rabl/configuration.rb

@@ -10,6 +10,12 @@
   rescue LoadError
 end
 
+# We load the plist library if it is available.
+begin
+  require 'plist'
+rescue LoadError
+end
+
 # Load MultiJSON
 require 'multi_json'
 
@@ -18,13 +24,15 @@ module Rabl
   class Configuration
     attr_accessor :include_json_root
     attr_accessor :include_msgpack_root
+    attr_accessor :include_plist_root
     attr_accessor :include_xml_root
     attr_accessor :include_bson_root
     attr_accessor :enable_json_callbacks
     attr_accessor :bson_check_keys
     attr_accessor :bson_move_id
     attr_writer   :msgpack_engine
     attr_writer   :bson_engine
+    attr_writer   :plist_engine
     attr_writer   :xml_options
     attr_accessor :cache_sources
 
@@ -33,6 +41,7 @@ class Configuration
     def initialize
       @include_json_root     = true
       @include_msgpack_root  = true
+      @include_plist_root    = true
       @include_xml_root      = false
       @include_bson_root     = true
       @enable_json_callbacks = false
@@ -41,6 +50,7 @@ def initialize
       @json_engine           = nil
       @msgpack_engine        = nil
       @bson_engine           = nil
+      @plist_engine          = nil
       @xml_options           = {}
       @cache_sources         = false
     end
@@ -67,6 +77,11 @@ def msgpack_engine
     # @return the Bson encoder/engine to use.
     def bson_engine
       @bson_engine || ::BSON
+
+    ##
+    # @return the Plist encoder/engine to use.
+    def plist_engine
+      @plist_engine || ::Plist::Emit
     end
 
     # Allows config options to be read like a hash

lib/rabl/engine.rb

@@ -62,6 +62,15 @@ def to_msgpack(options={})
     end
     alias_method :to_mpac, :to_msgpack
 
+    # Returns a plist representation of the data object
+    # to_plist(:root => true)
+    def to_plist(options={})
+      include_root = Rabl.configuration.include_plist_root
+      options = options.reverse_merge(:root => include_root, :child_root => include_root)
+      result = defined?(@_collection_name) ? { @_collection_name => to_hash(options) } : to_hash(options)
+      Rabl.configuration.plist_engine.dump(result)
+    end
+
     # Returns an xml representation of the data object
     # to_xml(:root => true)
     def to_xml(options={})

rabl.gemspec

@@ -29,4 +29,5 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'yajl-ruby'
   s.add_development_dependency 'msgpack', '~> 0.4.5'
   s.add_development_dependency 'bson', '~> 1.5.2'
+  s.add_development_dependency 'plist'
 end