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JSON for Django 1.9.x with Datetimes and Models
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class JSON: | |
def __init__(self): | |
import re | |
from dateutil.parser import parse | |
from django.db.models import Model | |
from django.apps import apps | |
pattern = re.compile(r'^(\d{4}-\d{2}-\d{2})?(T)?(\d{2}:\d{2}:\d{2}(?:\.\d{6})?(?:[+-]\d{2}:\d{2})?)?$') | |
def model_decoder(o): | |
model = o.pop('@model', None) | |
if model is None: return None, False | |
val = o.pop('@value', None) | |
if model is None: return None, False | |
return ModelDict(apps.get_model(model)).from_dict(val), True | |
def datetime_decoder(o): | |
val = o.get('@value', None) | |
if val is None: return None, False | |
match = pattern.match(val) | |
if match is None: return None, False | |
dat, sep, tim = [(v is not None) for v in match.groups()] | |
if (not (dat or tim or sep)) or (dat and tim and (not sep)): | |
return None, False | |
try: | |
res = parse(val) | |
except ValueError as e: | |
return None, False | |
if not dat: | |
res = res.time() | |
elif not tim: | |
res = res.date() | |
return res, True | |
decoders = dict(model= model_decoder, datetime= datetime_decoder) | |
def decoder(val, hook): | |
if not isinstance(val, dict): return hook(val) | |
typ = val.get('@type', None) | |
if typ is None: return hook(val) | |
handler = decoders.get(typ, None) | |
if handler is None: return hook(val) | |
res, ok = handler(val) | |
if ok: return res | |
return hook(val) | |
def encoder(obj): | |
if hasattr(obj, 'isoformat'): | |
res = { | |
'@type': 'datetime', | |
'@value': obj.isoformat(), | |
} | |
return res, True | |
elif isinstance(obj, Model): | |
model = type(obj) | |
obj = ModelDict(model).to_dict(obj) | |
res = { | |
'@type': 'model', | |
'@model': '%s.%s' % (model._meta.app_label, model.__name__), | |
'@value': obj, | |
} | |
return res, True | |
return None, False | |
self._encoder = encoder | |
self._decoder = decoder | |
def dump(self, | |
obj, | |
fp, | |
skipkeys=False, | |
ensure_ascii=True, | |
check_circular=True, | |
allow_nan=True, | |
cls=None, | |
*args, | |
**kwargs): | |
from json import dump, JSONEncoder | |
if cls is None: cls = JSONEncoder | |
class encoder(cls): | |
def default(this, obj): | |
res, ok = self._encoder(obj) | |
if ok: return res | |
return super(encoder, this).default(obj) | |
dump(obj, fp, skipkeys, ensure_ascii, check_circular, allow_nan, encoder, *args, **kwargs) | |
def dumps(self, | |
obj, | |
skipkeys=False, | |
ensure_ascii=True, | |
check_circular=True, | |
allow_nan=True, | |
cls=None, | |
*args, | |
**kwargs): | |
from json import dumps, JSONEncoder | |
if cls is None: cls = JSONEncoder | |
class encoder(cls): | |
def default(this, obj): | |
res, ok = self._encoder(obj) | |
if ok: return res | |
return super(encoder, this).default(obj) | |
res = dumps(obj, skipkeys, ensure_ascii, check_circular, allow_nan, encoder, *args, **kwargs) | |
if ensure_ascii: | |
res = res.encode() | |
return res | |
def load(self, fp, cls= None, object_hook= None, *args, **kwargs): | |
from json import load | |
if object_hook is None: object_hook = lambda o: o | |
return load(fp, cls, lambda o: self._decoder(o, object_hook), *args, **kwargs) | |
def loads(self, s, encoding= None, cls= None, object_hook= None, *args, **kwargs): | |
from json import loads | |
if object_hook is None: object_hook = lambda o: o | |
if isinstance(s, bytes): | |
if encoding is None: | |
s = s.decode() | |
else: | |
s = s.decode(encoding= encoding) | |
return loads(s, None, cls, lambda o: self._decoder(o, object_hook), *args, **kwargs) | |
class ModelDict(object): | |
def __init__(self, model): | |
self._model = model | |
def to_dict(self, instance, fields= None, exclude= None): | |
from django.db.models.fields.related import ManyToManyField, ForeignObjectRel | |
opts = self._model._meta | |
data = {} | |
for f in opts.get_fields(): | |
if (fields and (f.name not in fields)) or (exclude and (f.name in exclude)): | |
continue | |
if isinstance(f, ForeignObjectRel): | |
continue | |
if isinstance(f, ManyToManyField): | |
if not f.rel.through._meta.auto_created: | |
continue | |
if instance.pk is None: | |
data[f.name] = [] | |
else: | |
# MultipleChoiceWidget needs a list of pks, not object instances. | |
qs = f.value_from_object(instance) | |
if qs._result_cache is not None: | |
data[f.name] = [item.pk for item in qs] | |
else: | |
data[f.name] = list(qs.values_list('pk', flat=True)) | |
else: | |
data[f.name] = f.value_from_object(instance) | |
return data | |
def from_dict(self, data, fields= None, exclude= None): | |
from django.db.models.fields.related import ManyToManyField, RelatedField, ForeignObjectRel | |
from django.db.models import FileField | |
opts = self._model._meta | |
instance = self._model() | |
file_field_list = [] | |
for f in opts.get_fields(): | |
if (f.name not in data) or (fields and (f.name not in fields)) or (exclude and (f.name in exclude)): | |
continue | |
if isinstance(f, ForeignObjectRel): | |
continue | |
# Defer saving file-type fields until after the other fields, so a | |
# callable upload_to can use the values from other fields. | |
if isinstance(f, FileField): | |
file_field_list.append(f) | |
else: | |
value = data[f.name] | |
if isinstance(f, RelatedField): | |
def get_related_value(pk): | |
try: | |
if pk is not None: | |
return f.related_model.objects.get(pk= pk) | |
except: | |
pass | |
return None | |
if isinstance(f, ManyToManyField): | |
if not f.rel.through._meta.auto_created: | |
continue | |
value = [ o for o in (get_related_value(v) for v in value) if o is not None ] | |
else: | |
value = get_related_value(value) | |
if value is not None: | |
try: | |
f.save_form_data(instance, value) | |
except: | |
pass | |
for f in file_field_list: | |
f.save_form_data(instance, instance[f.name]) | |
if instance.pk is not None: | |
instance._state.adding = False | |
return instance |
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