[英]How do I turn MongoDB query into a JSON?
for p in db.collection.find({"test_set":"abc"}):
posts.append(p)
thejson = json.dumps({'results':posts})
return HttpResponse(thejson, mimetype="application/javascript")
在我的Django / Python代碼中,由於“ObjectID”,我無法從mongo查詢返回JSON。 錯誤說“ObjectID”不可序列化。
我需要做什么? 一種hacky方式是循環:
for p in posts:
p['_id'] = ""
這是一個簡單的示例,使用pymongo 2.2.1
import os
import sys
import json
import pymongo
from bson import BSON
from bson import json_util
if __name__ == '__main__':
try:
connection = pymongo.Connection('mongodb://localhost:27017')
database = connection['mongotest']
except:
print('Error: Unable to Connect')
connection = None
if connection is not None:
database["test"].insert({'name': 'foo'})
doc = database["test"].find_one({'name': 'foo'})
return json.dumps(doc, sort_keys=True, indent=4, default=json_util.default)
編寫一個可以處理ObjectIds的自定義序列化程序非常容易。 Django已經包含一個處理小數和日期的方法,所以你可以擴展它:
from django.core.serializers.json import DjangoJSONEncoder
from bson import objectid
class MongoAwareEncoder(DjangoJSONEncoder):
"""JSON encoder class that adds support for Mongo objectids."""
def default(self, o):
if isinstance(o, objectid.ObjectId):
return str(o)
else:
return super(MongoAwareEncoder, self).default(o)
現在你可以告訴json
使用你的自定義序列化器:
thejson = json.dumps({'results':posts}, cls=MongoAwareEncoder)
在Python 3.6上使用motor == 1.1 pymongo == 3.4.0對我有用的東西更簡單
from bson.json_util import dumps, loads
for mongo_doc in await cursor.to_list(length=10):
# mongo_doc is a <class 'dict'> returned from the async mongo driver, in this acse motor / pymongo.
# result of executing a simple find() query.
json_string = dumps(mongo_doc)
# serialize the <class 'dict'> into a <class 'str'>
back_to_dict = loads(json_string)
# to unserialize, thus return the string back to a <class 'dict'> with the original 'ObjectID' type.
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