Support for custom JSON serializer

docs/apidocs/index.txt

@@ -70,6 +70,13 @@ functionality of RPC4Django
     allowing cross site requests. See the Mozilla documentation on 
     `preflighted requests`_ for more details. Defaults to the empty string.
 
+.. envvar:: RPC4DJANGO_JSON_ENCODER
+
+    Subclass of ``rpc4django.jsonrpcdispatcher.json.JSONEncoder`` or string
+	pointing to the subclass. It can be used to serialize objects that can't
+	otherwise be serialized. Defaults to
+	``django.core.serializers.json.DjangoJSONEncoder``.
+
 .. _requests with credentials: https://developer.mozilla.org/en/HTTP_access_control#Requests_with_credentials
 .. _preflighted requests: https://developer.mozilla.org/en/HTTP_access_control#Preflighted_requests
 
@@ -102,4 +109,4 @@ Template tags
 
 .. automodule:: rpc4django.templatetags.rpctags
    :members:
-
+

rpc4django/jsonrpcdispatcher.py

@@ -40,7 +40,8 @@ class JSONRPCDispatcher:
     or error.
     '''
 
-    def __init__(self):
+    def __init__(self,json_encoder):
+        self.json_encoder = json_encoder
         self.methods = {}
 
     def register_function(self, method, external_name):
@@ -61,17 +62,16 @@ def _encode_result(self, jsonid, result, error):
             res['error'] = error
             res['error']['name'] = 'JSONRPCError'
             res['result'] = None
-
         try:
-            return json.dumps(res, indent=JSON_INDENT)
+            return json.dumps(res, indent=JSON_INDENT, cls=self.json_encoder)
         except:
             err = {'message': 'failed to encode return value',
                    'code': JSONRPC_SERVICE_ERROR,
                    'name': 'JSONRPCError'}
 
             res['result'] = None
             res['error'] = err
-            return json.dumps(res, indent=JSON_INDENT)
+            return json.dumps(res, indent=JSON_INDENT, cls=self.json_encoder)
 
     def dispatch(self, json_data, **kwargs):
         '''
@@ -146,4 +146,4 @@ def dispatch(self, json_data, **kwargs):
                      '" is not supported',  
                      'code': JSONRPC_PROCEDURE_NOT_FOUND_ERROR})
 
-
+

rpc4django/rpcdispatcher.py

@@ -210,11 +210,12 @@ class RPCDispatcher:
 
     '''
 
-    def __init__(self, url='', apps=[], restrict_introspection=False, restrict_ootb_auth=True):
+    def __init__(self, url='', apps=[], restrict_introspection=False,
+            restrict_ootb_auth=True, json_encoder=None):
         version = platform.python_version_tuple()
         self.url = url
         self.rpcmethods = []        # a list of RPCMethod objects
-        self.jsonrpcdispatcher = JSONRPCDispatcher()
+        self.jsonrpcdispatcher = JSONRPCDispatcher(json_encoder)
         self.xmlrpcdispatcher = XMLRPCDispatcher()
 
         if not restrict_introspection:

rpc4django/views.py

@@ -17,8 +17,10 @@
 from django.http import HttpResponse, Http404, HttpResponseForbidden
 from django.shortcuts import render_to_response
 from django.conf import settings
-from django.core.urlresolvers import reverse, NoReverseMatch
+from django.core.urlresolvers import reverse, NoReverseMatch, get_mod_func
+from django.utils.importlib import import_module
 from rpcdispatcher import RPCDispatcher
+from jsonrpcdispatcher import json
 from __init__ import version
 
 logger = logging.getLogger('rpc4django')
@@ -42,6 +44,8 @@
                                   'RPC4DJANGO_HTTP_ACCESS_CREDENTIALS', False)
 HTTP_ACCESS_ALLOW_ORIGIN = getattr(settings, 
                                   'RPC4DJANGO_HTTP_ACCESS_ALLOW_ORIGIN', '')
+JSON_ENCODER = getattr(settings, 'RPC4DJANGO_JSON_ENCODER',
+                       'django.core.serializers.json.DjangoJSONEncoder')
 
 # get a list of the installed django applications
 # these will be scanned for @rpcmethod decorators
@@ -232,8 +236,21 @@ def serve_rpc_request(request):
     URL = reverse(serve_rpc_request)
 except NoReverseMatch:
     URL = ''
-
+
+# resolve JSON_ENCODER to class if it's a string
+if isinstance(JSON_ENCODER, basestring):
+    mod_name, cls_name = get_mod_func(JSON_ENCODER)
+    json_encoder = getattr(import_module(mod_name), cls_name)
+else:
+    json_encoder = JSON_ENCODER
+
+
+if not issubclass(json_encoder, json.JSONEncoder):
+    raise Exception("RPC4DJANGO_JSON_ENCODER must be derived from "
+                    "rpc4django.jsonrpcdispatcher.JSONEncoder")
+
 # instantiate the rpcdispatcher -- this examines the INSTALLED_APPS
 # for any @rpcmethod decorators and adds them to the callable methods
-dispatcher = RPCDispatcher(URL, APPS, RESTRICT_INTROSPECTION, RESTRICT_OOTB_AUTH) 
+dispatcher = RPCDispatcher(URL, APPS, RESTRICT_INTROSPECTION,
+        RESTRICT_OOTB_AUTH, json_encoder)