json.rb in roda-2.3.0

- old
+ new

@@ -30,20 +30,38 @@
     # By default, only arrays and hashes are handled, but you
     # can specifically set the allowed classes to json by adding
     # using the :classes option when loading the plugin:
     #
     #   plugin :json, :classes=>[Array, Hash, Sequel::Model]
+    #
+    # By default objects are serialized with +to_json+, but you
+    # can pass in a custom serializer, which can be any object
+    # that responds to +call(object)+.
+    #
+    #   plugin :json, :serializer=>proc{|o| o.to_json(root: true)}
+    #
+    # If you need the request information during serialization, such
+    # as HTTP headers or query parameters, you can pass in the
+    # +:include_request+ option, which will pass in the request
+    # object as the second argument when calling the serializer.
+    #
+    #   plugin :json, include_request=>true, serializer=>proc{|o, request| ...}
     module Json
       OPTS = {}.freeze
+      DEFAULT_SERIALIZER = lambda{|o| o.to_json}
 
-      # Set the classes to automatically convert to JSON
+      # Set the classes to automatically convert to JSON, and the serializer to use.
       def self.configure(app, opts=OPTS)
         classes = opts[:classes] || [Array, Hash]
         app.opts[:json_result_classes] ||= []
         app.opts[:json_result_classes] += classes
         app.opts[:json_result_classes].uniq!
         app.opts[:json_result_classes].freeze
+
+        app.opts[:json_result_serializer] = opts[:serializer] || app.opts[:json_result_serializer] || DEFAULT_SERIALIZER
+
+        app.opts[:json_result_include_request] = opts[:include_request] || app.opts[:json_result_include_request]
       end
 
       module ClassMethods
         # The classes that should be automatically converted to json
         def json_result_classes
@@ -69,12 +87,14 @@
             super
           end
         end
 
         # Convert the given object to JSON.  Uses to_json by default,
-        # but can be overridden to use a different implementation.
+        # but can use a custom serializer passed to the plugin.
         def convert_to_json(obj)
-          obj.to_json
+          args = [obj]
+          args << self if roda_class.opts[:json_result_include_request]
+          roda_class.opts[:json_result_serializer].call(*args)
         end
       end
     end
 
     register_plugin(:json, Json)