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@jhrr
Created February 14, 2014 18:10
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JSON utilities for django
from django.db import models
from django.utils.functional import Promise
from django.utils.encoding import force_unicode
from django.utils import simplejson as json
from decimal import Decimal
from django.core import serializers
from django.conf import settings
from django.http import HttpResponse, HttpResponseForbidden, Http404
from django.core.mail import mail_admins
from django.db.models.query import QuerySet
from mongoengine.queryset.queryset import QuerySet as MongoQuerySet
from bson.objectid import ObjectId
import sys
import datetime
def decode(data):
if not data:
return data
return json.loads(data)
def encode(data, *args, **kwargs):
if type(data) == QuerySet: # Careful, ValuesQuerySet is a dict
# Django models
return serializers.serialize("json", data, *args, **kwargs)
else:
return json_encode(data, *args, **kwargs)
def json_encode(data, *args, **kwargs):
"""
The main issues with django's default json serializer is that properties that
had been added to an object dynamically are being ignored (and it also has
problems with some models).
"""
def _any(data):
ret = None
# Opps, we used to check if it is of type list, but that fails
# i.e. in the case of django.newforms.utils.ErrorList, which extends
# the type "list". Oh man, that was a dumb mistake!
if hasattr(data, 'canonical'):
ret = _any(data.canonical())
elif isinstance(data, list):
ret = _list(data)
elif isinstance(data, set):
ret = _list(list(data))
# Same as for lists above.
elif isinstance(data, dict):
ret = _dict(data)
elif isinstance(data, (Decimal, ObjectId)):
# json.dumps() cant handle Decimal
ret = str(data)
elif isinstance(data, models.query.QuerySet):
# Actually its the same as a list ...
ret = _list(data)
elif isinstance(data, MongoQuerySet):
# Actually its the same as a list ...
ret = _list(data)
elif isinstance(data, models.Model):
ret = _model(data)
# here we need to encode the string as unicode (otherwise we get utf-16 in the json-response)
elif isinstance(data, basestring):
ret = unicode(data)
elif isinstance(data, Exception):
ret = unicode(data)
# see http://code.djangoproject.com/ticket/5868
elif isinstance(data, Promise):
ret = force_unicode(data)
elif isinstance(data, datetime.datetime) or isinstance(data, datetime.date):
ret = str(data)
elif hasattr(data, 'to_json'):
ret = data.to_json()
else:
ret = data
return ret
def _model(data):
ret = {}
# If we only have a model, we only want to encode the fields.
for f in data._meta.fields:
ret[f.attname] = _any(getattr(data, f.attname))
# And additionally encode arbitrary properties that had been added.
fields = dir(data.__class__) + ret.keys()
add_ons = [k for k in dir(data) if k not in fields]
for k in add_ons:
ret[k] = _any(getattr(data, k))
return ret
def _list(data):
ret = []
for v in data:
ret.append(_any(v))
return ret
def _dict(data):
ret = {}
for k,v in data.items():
ret[str(k)] = _any(v)
return ret
if hasattr(data, 'to_json'):
data = data.to_json()
ret = _any(data)
return json.dumps(ret)
def json_view(func):
def wrap(request, *a, **kw):
response = func(request, *a, **kw)
return json_response(request, response)
if isinstance(func, HttpResponse):
return func
else:
return wrap
def json_response(request, response=None):
code = 200
if isinstance(response, HttpResponseForbidden):
return response
try:
if isinstance(response, dict):
response = dict(response)
if 'result' not in response:
response['result'] = 'ok'
authenticated = request.user.is_authenticated()
response['authenticated'] = authenticated
except KeyboardInterrupt:
# Allow keyboard interrupts through for debugging.
raise
except Http404:
raise Http404
except Exception, e:
# Mail the admins with the error
exc_info = sys.exc_info()
subject = 'JSON view error: %s' % request.path
try:
request_repr = repr(request)
except:
request_repr = 'Request repr() unavailable'
import traceback
message = 'Traceback:\n%s\n\nRequest:\n%s' % (
'\n'.join(traceback.format_exception(*exc_info)),
request_repr,
)
response = {'result': 'error',
'text': unicode(e)}
code = 500
if not settings.DEBUG:
mail_admins(subject, message, fail_silently=True)
else:
print '\n'.join(traceback.format_exception(*exc_info))
json = json_encode(response)
return HttpResponse(json, mimetype='application/json', status=code)
def main():
test = {1: True, 2: u"string", 3: 30}
json_test = json_encode(test)
print test, json_test
if __name__ == '__main__':
main()
import re
import simplejson
from django.http import HttpResponse
from django.conf import settings
class JSONResponse(HttpResponse):
def __init__(self, request, data):
indent = 2 if settings.DEBUG else None
mime = 'text/javascript' if settings.DEBUG else 'application/json'
content = simplejson.dumps(data, indent=indent)
callback = request.GET.get('callback')
if callback:
# Verify that the callback is secure
if re.compile(r'^[a-zA-Z][\w.]*$').match(callback):
content = '%s(%s);' % (callback, content)
super(JSONResponse, self).__init__(content=content, mimetype=mime)
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