change the dumps and loads hooks to accept string

The JSONRender and JSONParser need to be JSON serializable themselves,
so the loads_function and dumps_function are changed to accept strings
to work around it.

rest_framework/parsers.py

@@ -13,7 +13,7 @@ from django.http.multipartparser import MultiPartParserError, parse_header, Chun
 from rest_framework.compat import etree, six, yaml, force_text
 from rest_framework.exceptions import ParseError
 from rest_framework import renderers
-import json
+# import json
 import datetime
 import decimal
 
@@ -48,7 +48,7 @@ class JSONParser(BaseParser):
 
     media_type = 'application/json'
     renderer_class = renderers.UnicodeJSONRenderer
-    loads_function = json.loads
+    loads_function = 'json.loads'
 
     def parse(self, stream, media_type=None, parser_context=None):
         """
@@ -59,7 +59,12 @@ class JSONParser(BaseParser):
 
         try:
             data = stream.read().decode(encoding)
-            return self.loads_function(data)
+
+            components = self.loads_function.split('.')
+            loads = __import__(components[0])
+            for comp in components[1:]:
+                loads = getattr(loads, comp)
+            return loads(data)
         except ValueError as exc:
             raise ParseError('JSON parse error - %s' % six.text_type(exc))
 

rest_framework/renderers.py

@@ -9,7 +9,7 @@ REST framework also provides an HTML renderer the renders the browsable API.
 from __future__ import unicode_literals
 
 import copy
-import json
+# import json
 import django
 from django import forms
 from django.core.exceptions import ImproperlyConfigured
@@ -55,7 +55,7 @@ class JSONRenderer(BaseRenderer):
     encoder_class = encoders.JSONEncoder
     ensure_ascii = True
     charset = None
-    dumps_function = json.dumps
+    dumps_function = 'json.dumps'
     # JSON is a binary encoding, that can be encoded as utf-8, utf-16 or utf-32.
     # See: http://www.ietf.org/rfc/rfc4627.txt
     # Also: http://lucumr.pocoo.org/2013/7/19/application-mimetypes-and-encodings/
@@ -82,7 +82,12 @@ class JSONRenderer(BaseRenderer):
             except (ValueError, TypeError):
                 indent = None
 
-        ret = self.dumps_function(data, cls=self.encoder_class,
+        components = self.dumps_function.split('.')
+        dumps = __import__(components[0])
+        for comp in components[1:]:
+            dumps = getattr(dumps, comp)
+
+        ret = dumps(data, cls=self.encoder_class,
             indent=indent, ensure_ascii=self.ensure_ascii)
 
         # On python 2.x json.dumps() returns bytestrings if ensure_ascii=True,