Django Invalid JSON Response - json

Question

The following code produces the JSON given below. But when I validate it from JSON lint, it is invalid. What am I doing wrong here?
def json_candidate_get(request, model, m_id=None):
response = {'message' : 'Incorrect Json'}
try:
obj = model.objects.filter(pk=m_id)
ce = Candidate_profiles.objects.filter(pk=m_id)
cw = Candidate_company_profiles.objects.filter(pk=m_id)
response = json.dumps({ 'TechnologiesValue':[],'Technologies': [] })
except Exception as e:
logging.exception("Exception"+str(e))
return response
#is_login()
def candidate_create(request,m_id=None,token=None):
response_data = {'message': 'unsuccessfull'}
if token is not None:
try:
if request.method == 'GET':
response_data = json_candidate_get(request,Candidates,m_id)
print response_data
#response_data = serializers.serialize('json', response_data)
except Exception as e:
logging.exception(e)
return HttpResponse(response_data, content_type="application/json")
JSON:
{
TechnologiesValue: [0]
Technologies: [0]
}

Answer 1

The json.dumps function is meant to convert certain Python objects to a a JSON string. But you are already serializing your model instances (via QuerySets) to JSON strings, and json.dumps is trying to convert these strings into JSON all over again--it only knows that you've passed it str objects, not that these str objects represents JSON.
The JSON encoder used by json.dumps only knows how to convert a handful of built-in types:
Python 2
Python 3
So what you need to do is convert your model instances to one of these types. The easiest solution would be to use django.forms.models.model_to_dict on each element of your QuerySets, like so:
from django.forms.models import model_to_dict
response = json.dumps({
'candidate': [model_to_dict(x) for x in obj],
'CandidateEducationProfile': [model_to_dict(x) for x in ce],
...
)