如何将django Model对象转换为包含所有字段的dict ?理想情况下,所有字段都包含外键和editable=False。
让我详细说明一下。假设我有一个django模型,如下所示:
from django.db import models
class OtherModel(models.Model): pass
class SomeModel(models.Model):
normal_value = models.IntegerField()
readonly_value = models.IntegerField(editable=False)
auto_now_add = models.DateTimeField(auto_now_add=True)
foreign_key = models.ForeignKey(OtherModel, related_name="ref1")
many_to_many = models.ManyToManyField(OtherModel, related_name="ref2")
在终端中,我做了以下工作:
other_model = OtherModel()
other_model.save()
instance = SomeModel()
instance.normal_value = 1
instance.readonly_value = 2
instance.foreign_key = other_model
instance.save()
instance.many_to_many.add(other_model)
instance.save()
我想把它转换成下面的字典:
{'auto_now_add': datetime.datetime(2015, 3, 16, 21, 34, 14, 926738, tzinfo=<UTC>),
'foreign_key': 1,
'id': 1,
'many_to_many': [1],
'normal_value': 1,
'readonly_value': 2}
回答不满意的问题:
Django:将整个Model对象集转换为单个字典
如何将Django Model对象转换为字典,同时还保留外键?
我已经使用下一个函数转换模型到字典
def model_to_dict(obj):
return {x: obj.__dict__[x] for x in obj.__dict__ if x in {y.column for y in obj._meta.fields}}
例子
{'id': 8985,
'title': 'Dmitro',
'email_address': 'it9+8985@localhost',
'workspace_id': 'it9',
'archived': False,
'deleted': False,
'inbox': False,
'read': True,
'created_at': datetime.datetime(2022, 5, 5, 16, 55, 29, 791844, tzinfo= <UTC>),
'creator': 'An So',
'last_message_id': 500566,
'stat_data': {'count_messages': 1, 'count_attachments': 0},
'stat_dirty': False,
'assign_to_id': None,
'assigned_at': None,
'assignment_note': None,
'initial_last_update_ts': 1651769728,
'renamed_manually': False,
'unread_timestamp': datetime.datetime(2022, 5, 5, 16, 55, 29, 842507, tzinfo=<UTC>)}
{'id': 6670,
'email_id': 473962,
'message_id': 500620,
'filename': 'Screenshot.png',
'size': 6076854,
'mimetype': 'image/png',
'aws_key': 'dev/RLpdcza46KFpITDWO_kv_fg2732waccB43z5RmT9/Screenshot.png',
'aws_key1': '',
'aws_key_thumb': 'dev/iaCdvcZmUKq-gJim7HT33ID46Ng4WOdxx-TdVuIU/f4b0db49-7f2d-4def-bdc1-8e394f98727f.png',
's3stored_file_id': 4147}
我创建了一个小片段,利用django的model_to_dict,但遍历对象的关系。
对于循环依赖项,它终止递归并放入引用依赖项对象的字符串。您可以将其扩展为包含不可编辑字段。
我在测试期间使用它来创建模型快照。
from itertools import chain
from django.db.models.fields.files import FileField, ImageField
from django.forms.models import model_to_dict
def get_instance_dict(instance, already_passed=frozenset()):
"""Creates a nested dict version of a django model instance
Follows relationships recursively, circular relationships are terminated by putting
a model identificator `{model_name}:{instance.id}`.
Ignores image and file fields."""
instance_dict = model_to_dict(
instance,
fields=[
f
for f in instance._meta.concrete_fields
if not isinstance(f, (ImageField, FileField))
],
)
already_passed = already_passed.union(
frozenset((f"{instance.__class__.__name__}:{instance.id}",))
)
# Go through possible relationships
for field in chain(instance._meta.related_objects, instance._meta.concrete_fields):
if (
(field.one_to_one or field.many_to_one)
and hasattr(instance, field.name)
and (relation := getattr(instance, field.name))
):
if (
model_id := f"{relation.__class__.__name__}:{relation.id}"
) in already_passed:
instance_dict[field.name] = model_id
else:
instance_dict[field.name] = get_instance_dict(relation, already_passed)
if field.one_to_many or field.many_to_many:
relations = []
for relation in getattr(instance, field.get_accessor_name()).all():
if (
model_id := f"{relation.__class__.__name__}:{relation.id}"
) in already_passed:
relations.append(model_id)
else:
relations.append(get_instance_dict(relation, already_passed))
instance_dict[field.get_accessor_name()] = relations
return instance_dict
@Zags的解决方案太棒了!
不过,为了使它对JSON友好,我要为datefields添加一个条件。
奖金轮
如果你想要一个更好的python命令行显示的django模型,让你的models子类如下:
from django.db import models
from django.db.models.fields.related import ManyToManyField
class PrintableModel(models.Model):
def __repr__(self):
return str(self.to_dict())
def to_dict(self):
opts = self._meta
data = {}
for f in opts.concrete_fields + opts.many_to_many:
if isinstance(f, ManyToManyField):
if self.pk is None:
data[f.name] = []
else:
data[f.name] = list(f.value_from_object(self).values_list('pk', flat=True))
elif isinstance(f, DateTimeField):
if f.value_from_object(self) is not None:
data[f.name] = f.value_from_object(self).timestamp()
else:
data[f.name] = None
else:
data[f.name] = f.value_from_object(self)
return data
class Meta:
abstract = True
例如,如果我们这样定义我们的模型:
class OtherModel(PrintableModel): pass
class SomeModel(PrintableModel):
value = models.IntegerField()
value2 = models.IntegerField(editable=False)
created = models.DateTimeField(auto_now_add=True)
reference1 = models.ForeignKey(OtherModel, related_name="ref1")
reference2 = models.ManyToManyField(OtherModel, related_name="ref2")
调用sommodel .objects.first()现在给出如下输出:
{'created': 1426552454.926738,
'value': 1, 'value2': 2, 'reference1': 1, u'id': 1, 'reference2': [1]}