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?


当前回答

@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]}

其他回答

当我试图使用django-rest框架将django站点转换为API时,我遇到了这个问题。通常django会从数据库中返回三种类型的对象。它们包括一个查询集、一个模型实例和一个分页器对象。对我来说,这些是需要转换的。

查询集

queryset就像django中的模型对象列表。这是把它转换成字典的代码。

model_data=Model.object.all()# This returns a queryset object
model_to_dict=[model for model in model_data.values()]
return Response(model_to_dict,status=status.HTTP_200_OK)

模型实例

模型实例是模型的单个对象。

model_instance=Model.objects.get(pk=1)# This will return only a single model object
model_to_dict=model_to_dict(model_instance)
return Response(model_to_dict,status=status.HTTP_200_OK)

Paginator对象

分页器对象是一个包含特定页面的模型对象的对象。

model_queryset=Model.objects.all()
paginator = Paginator(model_queryset, 10)
try:
    selected_results = paginator.page(page)
except Exception:
    selected_results=result
paginator_to_dict=list(selected_results.object_list.values())
return Response(selected_results,status=status.HTTP_200_OK)

至少我是这么解决的。

(不是故意的)

好吧,它并不依赖于类型。我可能误解了最初的问题,所以如果是这样的话请原谅我。如果你创建serliazers.py,那么你在里面创建了有元类的类。

Class MyModelSerializer(serializers.ModelSerializer):
    class Meta:
        model = modelName
        fields =('csv','of','fields')

然后,当你在视图类中获得数据时,你可以:

model_data - Model.objects.filter(...)
serializer = MyModelSerializer(model_data, many=True)
return Response({'data': serilaizer.data}, status=status.HTTP_200_OK)

这就是我在很多地方所拥有的,它通过JSONRenderer返回漂亮的JSON。

正如我所说,这是由DjangoRestFramework提供的,所以值得研究一下。

你见过的最好的解决方案。

将django.db.models.Model实例和所有相关的ForeignKey, ManyToManyField和@Property函数字段转换为dict。

"""
Convert django.db.models.Model instance and all related ForeignKey, ManyToManyField and @property function fields into dict.
Usage:
    class MyDjangoModel(... PrintableModel):
        to_dict_fields = (...)
        to_dict_exclude = (...)
        ...
    a_dict = [inst.to_dict(fields=..., exclude=...) for inst in MyDjangoModel.objects.all()]
"""
import typing

import django.core.exceptions
import django.db.models
import django.forms.models


def get_decorators_dir(cls, exclude: typing.Optional[set]=None) -> set:
    """
    Ref: https://stackoverflow.com/questions/4930414/how-can-i-introspect-properties-and-model-fields-in-django
    :param exclude: set or None
    :param cls:
    :return: a set of decorators
    """
    default_exclude = {"pk", "objects"}
    if not exclude:
        exclude = default_exclude
    else:
        exclude = exclude.union(default_exclude)

    return set([name for name in dir(cls) if name not in exclude and isinstance(getattr(cls, name), property)])


class PrintableModel(django.db.models.Model):

    class Meta:
        abstract = True

    def __repr__(self):
        return str(self.to_dict())

    def to_dict(self, fields: typing.Optional[typing.Iterable]=None, exclude: typing.Optional[typing.Iterable]=None):
        opts = self._meta
        data = {}

        # support fields filters and excludes
        if not fields:
            fields = set()
        else:
            fields = set(fields)
        default_fields = getattr(self, "to_dict_fields", set())
        fields = fields.union(default_fields)

        if not exclude:
            exclude = set()
        else:
            exclude = set(exclude)
        default_exclude = getattr(self, "to_dict_exclude", set())
        exclude = exclude.union(default_exclude)

        # support syntax "field__childField__..."
        self_fields = set()
        child_fields = dict()
        if fields:
            for i in fields:
                splits = i.split("__")
                if len(splits) == 1:
                    self_fields.add(splits[0])
                else:
                    self_fields.add(splits[0])

                    field_name = splits[0]
                    child_fields.setdefault(field_name, set())
                    child_fields[field_name].add("__".join(splits[1:]))

        self_exclude = set()
        child_exclude = dict()
        if exclude:
            for i in exclude:
                splits = i.split("__")
                if len(splits) == 1:
                    self_exclude.add(splits[0])
                else:
                    field_name = splits[0]
                    if field_name not in child_exclude:
                        child_exclude[field_name] = set()
                    child_exclude[field_name].add("__".join(splits[1:]))

        for f in opts.concrete_fields + opts.many_to_many:
            if self_fields and f.name not in self_fields:
                continue
            if self_exclude and f.name in self_exclude:
                continue

            if isinstance(f, django.db.models.ManyToManyField):
                if self.pk is None:
                    data[f.name] = []
                else:
                    result = []
                    m2m_inst = f.value_from_object(self)
                    for obj in m2m_inst:
                        if isinstance(PrintableModel, obj) and hasattr(obj, "to_dict"):
                            d = obj.to_dict(
                                fields=child_fields.get(f.name),
                                exclude=child_exclude.get(f.name),
                            )
                        else:
                            d = django.forms.models.model_to_dict(
                                obj,
                                fields=child_fields.get(f.name),
                                exclude=child_exclude.get(f.name)
                            )
                        result.append(d)
                    data[f.name] = result
            elif isinstance(f, django.db.models.ForeignKey):
                if self.pk is None:
                    data[f.name] = []
                else:
                    data[f.name] = None
                    try:
                        foreign_inst = getattr(self, f.name)
                    except django.core.exceptions.ObjectDoesNotExist:
                        pass
                    else:
                        if isinstance(foreign_inst, PrintableModel) and hasattr(foreign_inst, "to_dict"):
                            data[f.name] = foreign_inst.to_dict(
                                fields=child_fields.get(f.name),
                                exclude=child_exclude.get(f.name)
                            )
                        elif foreign_inst is not None:
                            data[f.name] = django.forms.models.model_to_dict(
                                foreign_inst,
                                fields=child_fields.get(f.name),
                                exclude=child_exclude.get(f.name),
                            )

            elif isinstance(f, (django.db.models.DateTimeField, django.db.models.DateField)):
                v = f.value_from_object(self)
                if v is not None:
                    data[f.name] = v.isoformat()
                else:
                    data[f.name] = None
            else:
                data[f.name] = f.value_from_object(self)

        # support @property decorator functions
        decorator_names = get_decorators_dir(self.__class__)
        for name in decorator_names:
            if self_fields and name not in self_fields:
                continue
            if self_exclude and name in self_exclude:
                continue

            value = getattr(self, name)
            if isinstance(value, PrintableModel) and hasattr(value, "to_dict"):
                data[name] = value.to_dict(
                    fields=child_fields.get(name),
                    exclude=child_exclude.get(name)
                )
            elif hasattr(value, "_meta"):
                # make sure it is a instance of django.db.models.fields.Field
                data[name] = django.forms.models.model_to_dict(
                    value,
                    fields=child_fields.get(name),
                    exclude=child_exclude.get(name),
                )
            elif isinstance(value, (set, )):
                data[name] = list(value)
            else:
                data[name] = value

        return data

https://gist.github.com/shuge/f543dc2094a3183f69488df2bfb51a52

最简单的方式,

如果你的查询是Model.Objects.get(): Get()将返回单个实例,因此您可以直接从实例中使用__dict__。 model_dict = Model.Objects.get().__dict__ 过滤器()/ (): All ()/filter()将返回实例列表,因此您可以使用values()来获取对象列表。 model_values = Model.Objects.all().values()

将模型转换为字典并保留所有的外键模型关系。我使用了以下方法:

无详细名称

from django.forms.models import model_to_dict

instance = MyModel.objects.get(pk=1) # EXAMPLE

instance_dict = {key: getattr(instance, key) for key in model_to_dict(instance).keys()}

输出

{'foreign_key': [<OtherModel: OtherModel object>],
 'id': 1,
 'many_to_many': [<OtherModel: OtherModel object>],
 'normal_value': 1}

如果你想在模板中为外键关系显示__str__()值,这可能很有用。

将关键字参数fields=和exclude=包含到model_to_dict(instance,[…])中,使您可以过滤特定的字段。

详细名称

from django.forms.models import model_to_dict

instance = MyModel.objects.get(pk=1) # EXAMPLE

instance_dict = {instance._meta.get_field(key).verbose_name if hasattr(instance._meta.get_field(key), 'verbose_name') else key: getattr(instance, key) for key in model_to_dict(instance).keys()}

示例输出(如果给定示例有详细的名称)

{'Other Model:': [<OtherModel: OtherModel object>],
 'id': 1,
 'My Other Model:': [<OtherModel: OtherModel object>],
 'Normal Value:': 1}