add parser configuration to http transport, will add tests next commit

git-svn-id: https://google-api-ruby-client.googlecode.com/svn/trunk@18 c1d61fac-ed7f-fcc1-18f7-ff78120a04ef

lib/google/api_client/transport/http_transport.rb

@@ -14,8 +14,56 @@
 
 module Google #:nodoc:
   class APIClient #:nodoc:
+      ##
+      # Factory for HTTP backed client requests.
     class HTTPTransport
 
+      ##
+      # The default transport configuration values.  These may be overridden
+      # simply by passing in the same key to the constructor.
+      DEFAULTS = {
+        :parser => :json_parser
+      }
+
+      ##
+      # The default implementations of various parsers.  These may be overriden
+      # simply by passing the same key to the constructor.
+      PARSERS = {
+        :json_parser => JSONParser.new
+      }
+
+      ##
+      # Creates a new HTTP request factory.
+      #
+      # @param [Hash] options
+      # @return [Google::APIClient::Discovery] The HTTP request factory.
+      def initialize(options={})
+        @options = DEFAULTS.clone
+        @options.merge!(options)
+
+        # first check if user passed a parser then fallback on appropriate default
+        @parser = @options[@options[:parser]] || PARSERS[@options[:parser]]
+        unless @parser
+          raise ArgumentError,
+            'Invalid :parser configuration.'
+        end
+      end
+
+      ##
+      # Returns configuration of the transport.
+      #
+      # @return [Hash] The configuration options.
+      def options
+        return @options
+      end
+
+      ##
+      # Returns the parser used by the transport.
+      #
+      # @return The handle to the parser.
+      def parser
+       return @parser
+      end
     end
   end
 end