added support for jsonp callbacks

Author: fabrik42

lib/acts_as_api/config.rb

@@ -13,6 +13,8 @@ module Config
     # to get added an additional root node
     # with the name of the model.
     ADD_ROOT_NODE_FOR = [:json]
+    
+    ALLOW_JSONP_CALLBACK = false
 
     # The default name of a root node of a response
     # if no root paramter is passed in render_for_api
@@ -24,11 +26,14 @@ module Config
     mattr_accessor :dasherize_for
     mattr_accessor :add_root_node_for
     mattr_accessor :default_root
+    mattr_accessor :allow_jsonp_callback    
 
     @@accepted_api_formats = ACCEPTED_API_FORMATS
     @@dasherize_for        = DASHERIZE_FOR
     @@add_root_node_for    = ADD_ROOT_NODE_FOR
     @@default_root         = DEFAULT_ROOT
+    @@allow_jsonp_callback = ALLOW_JSONP_CALLBACK    
+    
 
   end
 

lib/acts_as_api/rendering.rb

@@ -67,6 +67,8 @@ def render_for_api(api_template, render_options)
 
       # create the Hash as response
       output_params[api_format] = api_response
+      
+      output_params[:callback] = params[:callback] if ActsAsApi::Config.allow_jsonp_callback && params[:callback]
 
       render output_params