I have a django app which was running on 1.4.2
version and working completely fine, but recently i updated it to django 1.6.5
and facing some wierd errors like below
Actually i am getting this during user/client registration process in my site functionality
Request URL: http://example.com/client/registration/
Django Version: 1.6.5
Exception Type: TypeError
Exception Value: <Client: test one> is not JSON serializable
Exception Location: /usr/lib/python2.7/json/encoder.py in default, line 184
Python Executable: /home/user/.virtualenvs/test_proj/bin/python
Python Version: 2.7.5
traceback
Traceback:
File "/home/user/.virtualenvs/test_proj/local/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response
199. response = middleware_method(request, response)
File "/home/user/.virtualenvs/test_proj/local/lib/python2.7/site-packages/django/contrib/sessions/middleware.py" in process_response
38. request.session.save()
File "/home/user/.virtualenvs/test_proj/local/lib/python2.7/site-packages/django/contrib/sessions/backends/db.py" in save
57. session_data=self.encode(self._get_session(no_load=must_create)),
File "/home/user/.virtualenvs/test_proj/local/lib/python2.7/site-packages/django/contrib/sessions/backends/base.py" in encode
87. serialized = self.serializer().dumps(session_dict)
File "/home/user/.virtualenvs/test_proj/local/lib/python2.7/site-packages/django/core/signing.py" in dumps
88. return json.dumps(obj, separators=(',', ':')).encode('latin-1')
File "/usr/lib/python2.7/json/__init__.py" in dumps
250. sort_keys=sort_keys, **kw).encode(obj)
File "/usr/lib/python2.7/json/encoder.py" in encode
207. chunks = self.iterencode(o, _one_shot=True)
File "/usr/lib/python2.7/json/encoder.py" in iterencode
270. return _iterencode(o, 0)
File "/usr/lib/python2.7/json/encoder.py" in default
184. raise TypeError(repr(o) + " is not JSON serializable")
Exception Type: TypeError at /client/registration/
Exception Value: <Client: test one> is not JSON serializable
I am confused on why the above json error has been appearing after updation and by the way i am using a customized json field in some of my models as below
proj/utils.py
from django.db import models
from django.utils import simplejson as json
from django.core.serializers.json import DjangoJSONEncoder
class JSONField(models.TextField):
'''JSONField is a generic textfield that neatly serializes/unserializes
JSON objects seamlessly'''
# Used so to_python() is called
__metaclass__ = models.SubfieldBase
def to_python(self, value):
'''Convert our string value to JSON after we load it from the DB'''
if value == '':
return None
try:
if isinstance(value, basestring):
return json.loads(value)
except ValueError:
pass
return value
def get_db_prep_save(self, value, connection=None):
'''Convert our JSON object to a string before we save'''
if not value or value == '':
return None
if isinstance(value, (dict, list)):
value = json.dumps(value, mimetype="application/json")
return super(JSONField, self).get_db_prep_save(value, connection=connection)
from south.modelsinspector import add_introspection_rules
add_introspection_rules([], ["^proj\.util\.jsonfield\.JSONField"])
settings.py
SERIALIZATION_MODULES = {
'custom_json': 'proj.util.json_serializer',
}
json_serializer.py
from django.core.serializers.json import Serializer as JSONSerializer
from django.utils.encoding import is_protected_type
# JSONFields that are normally incorrectly serialized as strings
json_fields = ['field_1', 'field_2']
class Serializer(JSONSerializer):
"""
A fix on JSONSerializer in order to prevent stringifying JSONField data.
"""
def handle_field(self, obj, field):
value = field._get_val_from_obj(obj)
# Protected types (i.e., primitives like None, numbers, dates,
# and Decimals) are passed through as is. All other values are
# converted to string first.
if is_protected_type(value) or field.name in json_fields:
self._current[field.name] = value
else:
self._current[field.name] = field.value_to_string(obj)
So how to solve the above error ? can some one give me an explanation of what happening to cause the error ?
Django 1.6 changed the serializer from pickle to json. pickle can serialize things that json can't.
You can change the value of SESSION_SERIALIZER in your settings.py
to get back the behaviour from Django before version 1.6.
SESSION_SERIALIZER = 'django.contrib.sessions.serializers.PickleSerializer'
You might want to read about session serialization in the documentation.