JSON 使用 simplejson 序列化 Django 模型

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时间:2020-09-03 17:24:39  来源:igfitidea点击:

JSON Serializing Django Models with simplejson

djangojsonserializationdjango-queryset

提问by Zack

I'd like to use simplejson to serialize a Django model. Django's serializer doesn't support dictionaries... and simplejson doesn't support Django Querysets. This is quite a conundrum.

我想使用 simplejson 来序列化 Django 模型。Django 的序列化程序不支持字典……并且 simplejson 不支持 Django 查询集。这是一个难题。

In the model there's sponsors that have a Foreign Key to sponsor level, I'm trying to group all the sponsors that belong to a certain sponsor level together. Here's the code that generates the list:

在模型中,赞助商具有赞助商级别的外键,我试图将属于某个赞助商级别的所有赞助商组合在一起。这是生成列表的代码:

from django.shortcuts import get_list_or_404
from special_event.models import Sponsor, SponsorLevel

sponsor_dict = {}

roadie_sponsors = get_list_or_404(Sponsor, level__category = SponsorLevel.ROADIE_CHOICE)

for item in roadie_sponsors:
    try:
        sponsor_dict[item.level.name].append(item)
    except KeyError:
        sponsor_dict[item.level.name] = [item]

Here's what sponsor_dictlooks like once it's "made"

这是sponsor_dict“制造”后的样子

{
    'Fan': [<Sponsor: Fan Sponsor>], 
    'VIP': [<Sponsor: VIP Sponsor>],
    'Groupie': [<Sponsor: Groupie Sponsor>],
    'Silver': [<Sponsor: Silver Sponsor>],
    'Bronze': [<Sponsor: Another Bronze Sponsor>, <Sponsor: Bronze Sponsor>]
}

I only added one sponsor in each level, except for bronze, just to show how it works. All I want to do is get it "all" into JSON so jQuery can interpret it easily. Can Django's other serializers (like XML or YAML) accomplish this? Can I "extend" the Django JSON Serializer to handle dictionaries or "extend" simplejson to handle Django QuerySet objects?

我只在每个级别添加了一个赞助商,除了铜牌,只是为了展示它是如何运作的。我想要做的就是将它“全部”放入 JSON 中,以便 jQuery 可以轻松解释它。Django 的其他序列化程序(如 XML 或 YAML)能做到这一点吗?我可以“扩展” Django JSON Serializer 以处理字典或“扩展” simplejson 以处理 Django QuerySet 对象吗?

回答by Clément

I would go with extending simplejson. Basically, you want to plug in django's serialization when the JSON encoder encounters a QuerySet. You could use something like:

我会去扩展simplejson。基本上,您希望在 JSON 编码器遇到 QuerySet 时插入 django 的序列化。你可以使用类似的东西:

from json import dumps, loads, JSONEncoder

from django.core.serializers import serialize
from django.db.models.query import QuerySet
from django.utils.functional import curry

class DjangoJSONEncoder(JSONEncoder):
    def default(self, obj):
        if isinstance(obj, QuerySet):
            # `default` must return a python serializable
            # structure, the easiest way is to load the JSON
            # string produced by `serialize` and return it
            return loads(serialize('json', obj))
        return JSONEncoder.default(self,obj)

# partial function, we can now use dumps(my_dict) instead
# of dumps(my_dict, cls=DjangoJSONEncoder)
dumps = curry(dumps, cls=DjangoJSONEncoder)

For more info on defaultmethod, have a look at simplejson documentation. Put that in a python module, then import dumpsand you're good to go. But note that this function will only help you serializing QuerySetinstances, not Modelinstances directly.

有关default方法的更多信息,请查看simplejson 文档。把它放在一个 python 模块中,然后导入dumps,你就可以开始了。但请注意,此功能只会帮助您序列化QuerySet实例,而不是Model直接实例化。

回答by selaux

A really flexible way to serialize most structures in django is to use the serializer class found here

在 Django 中序列化大多数结构的一种非常灵活的方法是使用此处找到的序列化器类

回答by jcage

based on Clement's answer, I did this to get models into JSON as well.

根据 Clement 的回答,我这样做也是为了将模型导入 JSON。

def toJSON(obj):
   if isinstance(obj, QuerySet):
       return simplejson.dumps(obj, cls=DjangoJSONEncoder)
   if isinstance(obj, models.Model):
       #do the same as above by making it a queryset first
       set_obj = [obj]
       set_str = simplejson.dumps(simplejson.loads(serialize('json', set_obj)))
       #eliminate brackets in the beginning and the end 
       str_obj = set_str[1:len(set_str)-2]
   return str_obj