I have a Django view that is raising an error when the template tries to render:
TypeError: is not JSON serializable
(Where 76 is the id field) Here is the view
def view2(request, model1object_id):
model1object = Model1.objects.get(pk=model1object_id)
# HERE
session_object = request.session.get('content')
if session_object:
del request.session['content']
request.session['content'] = model1object
context = {
"model1object": model1object,
....
}
return render(request, 'app/template2.html', context)
Here's my model for Model1:
class Model1(models.Model):
date_field = models.DateField()
another_field = models.CharField(max_length= 50, default="...")
def __str__(self):
return unicode(self.id) or u''
def get_absolute_url(self):
return reverse('app:model1', kwargs={'id': self.id})
EDIT: Traceback ->
Traceback (most recent call last):
File "/Library/Python/2.7/site-packages/django/core/handlers/base.py", line 235, in get_response
response = middleware_method(request, response)
File "/Library/Python/2.7/site-packages/django/contrib/sessions/middleware.py", line 50, in process_response
request.session.save()
File "/Library/Python/2.7/site-packages/django/contrib/sessions/backends/db.py", line 82, in save
obj = self.create_model_instance(data)
File "/Library/Python/2.7/site-packages/django/contrib/sessions/backends/db.py", line 68, in create_model_instance
session_data=self.encode(data),
File "/Library/Python/2.7/site-packages/django/contrib/sessions/backends/base.py", line 91, in encode
serialized = self.serializer().dumps(session_dict)
File "/Library/Python/2.7/site-packages/django/core/signing.py", line 95, in dumps
return json.dumps(obj, separators=(',', ':')).encode('latin-1')
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/__init__.py", line 250, in dumps
sort_keys=sort_keys, **kw).encode(obj)
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/encoder.py", line 207, in encode
chunks = self.iterencode(o, _one_shot=True)
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/encoder.py", line 270, in iterencode
return _iterencode(o, 0)
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/encoder.py", line 184, in default
raise TypeError(repr(o) + " is not JSON serializable")
TypeError: <Model1: 76> is not JSON serializable
thanks
The error is because you are trying to save a model instance in the session, and the session middleware cannot serialize it to JSON.
request.session['content'] = model1object
It may be enough to store the id of the object instead of the object itself.
request.session['content_id'] = model1object.id
...
# retrieve from db later
model1object = Model1.objects.get(id=request.session['content_id'])
If you need to store more information in the session than the id, then you'll have to convert it to a format that is JSON serializable. For a simple model, it might be easiest to create a Python dict.
request.session['content'] = {
'id': model1object.id,
'name': model1object.name,
...
}
For more complicated models, you could look at the docs on serializing Django objects.