我有一个基本的字典如下:

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

当我尝试做jsonify(sample)时,我得到:

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

我该怎么做才能使我的字典样本克服上面的错误呢?

注意:虽然它可能不相关,字典是从mongodb的记录检索中生成的,当我打印出str(sample['somedate'])时,输出是2012-08-08 21:46:24.862000。


当前回答

您必须使用json.dumps的cls参数提供一个自定义编码器类。引用文件中的内容:

>>> import json
>>> class ComplexEncoder(json.JSONEncoder):
...     def default(self, obj):
...         if isinstance(obj, complex):
...             return [obj.real, obj.imag]
...         return json.JSONEncoder.default(self, obj)
...
>>> dumps(2 + 1j, cls=ComplexEncoder)
'[2.0, 1.0]'
>>> ComplexEncoder().encode(2 + 1j)
'[2.0, 1.0]'
>>> list(ComplexEncoder().iterencode(2 + 1j))
['[', '2.0', ', ', '1.0', ']']

这里使用了复数作为示例,但是您也可以轻松地创建一个类来编码日期(除了我认为JSON对于日期有点模糊)

其他回答

您必须使用json.dumps的cls参数提供一个自定义编码器类。引用文件中的内容:

>>> import json
>>> class ComplexEncoder(json.JSONEncoder):
...     def default(self, obj):
...         if isinstance(obj, complex):
...             return [obj.real, obj.imag]
...         return json.JSONEncoder.default(self, obj)
...
>>> dumps(2 + 1j, cls=ComplexEncoder)
'[2.0, 1.0]'
>>> ComplexEncoder().encode(2 + 1j)
'[2.0, 1.0]'
>>> list(ComplexEncoder().iterencode(2 + 1j))
['[', '2.0', ', ', '1.0', ']']

这里使用了复数作为示例,但是您也可以轻松地创建一个类来编码日期(除了我认为JSON对于日期有点模糊)

在使用sqlalchemy在类中编写序列化装饰器时,我得到了相同的错误消息。所以不要:

Class Puppy(Base):
    ...
    @property
    def serialize(self):
        return { 'id':self.id,
                 'date_birth':self.date_birth,
                  ...
                }

我只是借用了jgbarah使用isoformat()的想法,并将原始值附加到isoformat(),这样它现在看起来就像:

                  ...
                 'date_birth':self.date_birth.isoformat(),
                  ...

Another approach is to adopt a concept from FEEL (the Friendly Enough Expression Language) defined in DMN (Decision Model Notation) - namely @strings. Any string starting with @" and ending with " is decoded separately with FEEL decoding. Of course the sender and the receiver have to agree to this convention, but ... the code below lets you encode lots of other things as well as dates, times, date/times, timedeltas. You can encode year/month durations and ranges (so long as you except a 4 element tuple of chr, expr, expr, chr as being a good representation of a range - where the two chrs are open/close brackets). So, @"P4Y2M" is a duration of 4 years and 2 months. @"P2DT5H" is a timedelta of 2 days and 4 hours, @"(2021-01-02 .. 2021-12-31)" is a year range.

下面的代码可用于序列化和反序列化@strings。

import datetime
import pySFeel

parser = pySFeel.SFeelParser()


def convertAtString(thisString):
    # Convert an @string
    (status, newValue) = parser.sFeelParse(thisString[2:-1])
    if 'errors' in status:
        return thisString
    else:
        return newValue


def convertIn(newValue):
    if isinstance(newValue, dict):
        for key in newValue:
            if isinstance(newValue[key], int):
                newValue[key] = float(newValue[key])
            elif isinstance(newValue[key], str) and (newValue[key][0:2] == '@"') and (newValue[key][-1] == '"'):
                newValue[key] = convertAtString(newValue[key])
            elif isinstance(newValue[key], dict) or isinstance(newValue[key], list):
                newValue[key] = convertIn(newValue[key])
    elif isinstance(newValue, list):
        for i in range(len(newValue)):
            if isinstance(newValue[i], int):
                newValue[i] = float(newValue[i])
            elif isinstance(newValue[i], str) and (newValue[i][0:2] == '@"') and (newValue[i][-1] == '"'):
                newValue[i] = convertAtString(newValue[i])
            elif isinstance(newValue[i], dict) or isinstance(newValue[i], list):
                newValue[i] = convertIn(newValue[i])
    elif isinstance(newValue, str) and (newValue[0:2] == '@"') and (newValue[-1] == '"'):
        newValue = convertAtString(newValue)
    return newValue


  def convertOut(thisValue):
      if isinstance(thisValue, datetime.date):
          return '@"' + thisValue.isoformat() + '"'
      elif isinstance(thisValue, datetime.datetime):
          return '@"' + thisValue.isoformat(sep='T') + '"'
      elif isinstance(thisValue, datetime.time):
          return '@"' + thisValue.isoformat() + '"'
      elif isinstance(thisValue, datetime.timedelta):
          sign = ''
          duration = thisValue.total_seconds()
          if duration < 0:
              duration = -duration
              sign = '-'
          secs = duration % 60
          duration = int(duration / 60)
          mins = duration % 60
          duration = int(duration / 60)
          hours = duration % 24
          days = int(duration / 24)
          return '@"%sP%dDT%dH%dM%fS"' % (sign, days, hours, mins, secs)
      elif isinstance(thisValue, bool):
          return thisValue:
      elif thisValue is None:
          return thisValue:
      elif isinstance(thisValue, int):
          sign = ''
          if thisValue < 0:
              thisValue = -thisValue
              sign = '-'
          years = int(thisValue / 12)
          months = (thisValue % 12)
          return '@"%sP%dY%dM"' % (sign, years, months)
      elif isinstance(thisValue, tuple) and (len(thisValue) == 4):
          (lowEnd, lowVal, highVal, highEnd) = thisValue
          return '@"' + lowEnd + str(lowVal) + ' .. ' + str(highVal) + highEnd
      elif thisValue is None:
          return 'null'
      elif isinstance(thisValue, dict):
          for item in thisValue:
              thisValue[item] = convertOut(thisValue[item])
          return thisValue
      elif isinstance(thisValue, list):
          for i in range(len(thisValue)):
              thisValue[i] = convertOut(thisValue[i])
          return thisValue
      else:
          return thisValue

如果在视图中使用结果,请确保返回正确的响应。根据API, jsonify执行以下操作:

使用给定参数的JSON表示创建一个Response 用一个application/json mimetype。

使用json模拟此行为。转储您必须添加几行额外的代码。

response = make_response(dumps(sample, cls=CustomEncoder))
response.headers['Content-Type'] = 'application/json'
response.headers['mimetype'] = 'application/json'
return response

您还应该返回一个dict以完全复制jsonify的响应。整个文件是这样的

from flask import make_response
from json import JSONEncoder, dumps


class CustomEncoder(JSONEncoder):
    def default(self, obj):
        if set(['quantize', 'year']).intersection(dir(obj)):
            return str(obj)
        elif hasattr(obj, 'next'):
            return list(obj)
        return JSONEncoder.default(self, obj)

@app.route('/get_reps/', methods=['GET'])
def get_reps():
    sample = ['some text', <datetime object>, 123]
    response = make_response(dumps({'result': sample}, cls=CustomEncoder))
    response.headers['Content-Type'] = 'application/json'
    response.headers['mimetype'] = 'application/json'
    return response

我的快速和肮脏的JSON转储吃日期和一切:

json.dumps(my_dictionary, indent=4, sort_keys=True, default=str)

Default是一个应用于不可序列化对象的函数。 在这种情况下,它是str,所以它只是把所有它不知道的东西转换成字符串。这对于序列化很好,但在反序列化时就不太好了(因此是“快速和肮脏”),因为任何东西都可能在没有警告的情况下被字符串化,例如函数或numpy数组。