Added functionality and test.

jwt/__init__.py

@@ -215,7 +215,7 @@ def header(jwt):
         raise DecodeError('Invalid header encoding')
 
 
-def encode(payload, key, algorithm='HS256', headers=None):
+def encode(payload, key, algorithm='HS256', headers=None, json_encoder=None):
     segments = []
 
     if algorithm is None:
@@ -231,7 +231,9 @@ def encode(payload, key, algorithm='HS256', headers=None):
     if headers:
         header.update(headers)
 
-    json_header = json.dumps(header, separators=(',', ':')).encode('utf-8')
+    json_header = json.dumps(header,
+                             separators=(',', ':'),
+                             cls=json_encoder).encode('utf-8')
     segments.append(base64url_encode(json_header))
 
     # Payload
@@ -240,7 +242,9 @@ def encode(payload, key, algorithm='HS256', headers=None):
         if isinstance(payload.get(time_claim), datetime):
             payload[time_claim] = timegm(payload[time_claim].utctimetuple())
 
-    json_payload = json.dumps(payload, separators=(',', ':')).encode('utf-8')
+    json_payload = json.dumps(payload,
+                              separators=(',', ':'),
+                              cls=json_encoder).encode('utf-8')
     segments.append(base64url_encode(json_payload))
 
     # Segments

tests/test_jwt.py

@@ -1,9 +1,13 @@
 from __future__ import unicode_literals
+
 from calendar import timegm
 from datetime import datetime
+from decimal import Decimal
+
 import sys
 import time
 import unittest
+import json
 
 import jwt
 
@@ -811,6 +815,26 @@ def test_raise_exception_token_without_issuer(self):
             jwt.InvalidIssuer,
             lambda: jwt.decode(token, 'secret', issuer=issuer))
 
+    def test_custom_json_encoder(self):
+
+        class CustomJSONEncoder(json.JSONEncoder):
+
+            def default(self, o):
+                if isinstance(o, Decimal):
+                    return 'it worked'
+                return super(CustomJSONEncoder, self).default(o)
+
+        data = {
+            'some_decimal': Decimal('2.2')
+        }
+
+        with self.assertRaises(TypeError):
+            jwt.encode(data, 'secret')
+
+        token = jwt.encode(data, 'secret', json_encoder=CustomJSONEncoder)
+        payload = jwt.decode(token, 'secret')
+        self.assertDictEqual(payload, {'some_decimal': 'it worked'})
+
 
 if __name__ == '__main__':
     unittest.main()