如何克服"datetime.datetime无法JSON序列化"? [英] How to overcome "datetime.datetime not JSON serializable"?

问题描述

我的基本要求如下:

sample = {}
sample['title'] = "String"
sample['somedate'] = somedatetimehere

当我尝试执行jsonify(sample)时，我得到:

When I try to do jsonify(sample) I get:

TypeError: datetime.datetime(2012, 8, 8, 21, 46, 24, 862000) is not JSON serializable

我该怎么做才能使我的词典示例克服上面的错误?

What can I do such that my dictionary sample can overcome the error above?

注意:尽管可能不相关，但字典是从mongodb中检索记录生成的，在我打印出str(sample['somedate'])时，输出为2012-08-08 21:46:24.862000.

Note: Though it may not be relevant, the dictionaries are generated from the retrieval of records out of mongodb where when I print out str(sample['somedate']), the output is 2012-08-08 21:46:24.862000.

推荐答案

已于2018年更新

原始答案适应了MongoDB日期"字段的表示方式:

Updated for 2018

The original answer accommodated the way MongoDB "date" fields were represented as:

{"$date": 1506816000000}

如果您想使用通用Python解决方案将datetime序列化为json，请查看 @jjmontes的答案无需依赖项的快速解决方案.

If you want a generic Python solution for serializing datetime to json, check out @jjmontes' answer for a quick solution which requires no dependencies.

由于您正在使用mongoengine(每个注释)并且pymongo是一个依赖项，因此pymongo具有内置实用程序来帮助进行json序列化:
http://api.mongodb.org/python/1.10.1 /api/bson/json_util.html

As you are using mongoengine (per comments) and pymongo is a dependency, pymongo has built-in utilities to help with json serialization:
http://api.mongodb.org/python/1.10.1/api/bson/json_util.html

用法示例(序列化):

from bson import json_util
import json

json.dumps(anObject, default=json_util.default)

用法示例(反序列化):

Example usage (deserialization):

json.loads(aJsonString, object_hook=json_util.object_hook)

---

Django

Django提供了本机DjangoJSONEncoder序列化程序，可以正确处理这种情况.

---

Django

Django provides a native DjangoJSONEncoder serializer that deals with this kind of properly.

请参见 https://docs.djangoproject.com/en/dev/topic/serialization/#djangojsonencoder

from django.core.serializers.json import DjangoJSONEncoder

return json.dumps(
  item,
  sort_keys=True,
  indent=1,
  cls=DjangoJSONEncoder
)

我注意到DjangoJSONEncoder和使用自定义default之间的一个区别是这样的:

One difference I've noticed between DjangoJSONEncoder and using a custom default like this:

import datetime
import json

def default(o):
    if isinstance(o, (datetime.date, datetime.datetime)):
        return o.isoformat()

return json.dumps(
  item,
  sort_keys=True,
  indent=1,
  default=default
)

是Django剥离了一些数据吗?

Is that Django strips a bit of the data:

 "last_login": "2018-08-03T10:51:42.990", # DjangoJSONEncoder 
 "last_login": "2018-08-03T10:51:42.990239", # default

因此，在某些情况下，您可能需要注意这一点.

So, you may need to be careful about that in some cases.

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