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# -*- coding: utf-8 -*-
"""
JSONField automatically serializes most Python terms to JSON data.
Creates a TEXT field with a default value of "{}". See test_json.py for
more information.
from django.db import models
from django_extensions.db.fields import json
class LOL(models.Model):
extra = json.JSONField()
"""
from __future__ import absolute_import
import json
import six
import warnings
from django.conf import settings
from django.core.serializers.json import DjangoJSONEncoder
from django.db import models
def dumps(value):
return DjangoJSONEncoder().encode(value)
def loads(txt):
value = json.loads(
txt,
encoding=settings.DEFAULT_CHARSET
)
return value
class JSONDict(dict):
"""
Hack so repr() called by dumpdata will output JSON instead of
Python formatted data. This way fixtures will work!
"""
def __repr__(self):
return dumps(self)
class JSONList(list):
"""
As above
"""
def __repr__(self):
return dumps(self)
class JSONField(models.TextField):
"""JSONField is a generic textfield that neatly serializes/unserializes
JSON objects seamlessly. Main thingy must be a dict object."""
def __init__(self, *args, **kwargs):
warnings.warn("Django 1.9 features a native JsonField, this JSONField will "
"be removed somewhere after Django 1.8 becomes unsupported.",
DeprecationWarning)
kwargs['default'] = kwargs.get('default', dict)
models.TextField.__init__(self, *args, **kwargs)
def get_default(self):
if self.has_default():
default = self.default
if callable(default):
default = default()
return self.to_python(default)
return super(JSONField, self).get_default()
def to_python(self, value):
"""Convert our string value to JSON after we load it from the DB"""
if value is None or value == '':
return {}
if isinstance(value, six.string_types):
res = loads(value)
else:
res = value
if isinstance(res, dict):
return JSONDict(**res)
elif isinstance(res, list):
return JSONList(res)
return value
def get_prep_value(self, value):
if not isinstance(value, six.string_types):
return dumps(value)
return super(models.TextField, self).get_prep_value(value)
def from_db_value(self, value, expression, connection, context):
return self.to_python(value)
def get_db_prep_save(self, value, connection, **kwargs):
"""Convert our JSON object to a string before we save"""
if value is None and self.null:
return None
# default values come in as strings; only non-strings should be
# run through `dumps`
if not isinstance(value, six.string_types):
value = dumps(value)
return value
def deconstruct(self):
name, path, args, kwargs = super(JSONField, self).deconstruct()
if self.default == '{}':
del kwargs['default']
return name, path, args, kwargs
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