added basic json parser support and tests

git-svn-id: https://google-api-ruby-client.googlecode.com/svn/trunk@23 c1d61fac-ed7f-fcc1-18f7-ff78120a04ef

lib/google/api_client/parser/json_parser.rb

@@ -16,8 +16,27 @@ require 'json'
 
 module Google #:nodoc:
   class APIClient #:nodoc:
+
+    ##
+    # Provides a consistent interface by which to parse request and response
+    # content.
+    # TODO(mattpok): ensure floats, URLs, dates are parsed correctly
     class JSONParser
 
+      def generate(hash)
+        # JSON parser used can accept arrays as well, but we will limit
+        # to only allow hash to JSON string parsing to keep a simple interface
+        unless hash.instance_of? Hash
+          raise ArgumentError,
+            "JSON generate expected a Hash but got a #{hash.class}."
+        end
+
+        return JSON.generate hash
+      end
+
+      def parse(json_string)
+        return JSON.parse json_string
+      end
     end
   end
 end