convert pymongo cursor to json - pymongo

Question

I know this is a fairly common problem. I'm writing a small Flask app and I'm trying to feed some queries back to the view.
I've connected to my local MongoDB setup, and made a successful query - but I can't generate a json object with it.
The most common solution I've seen is to import json_util from pymongo i.e.
import json
from pymongo import json_util
results = connection.get_collection('papayas_papaya')
results = results.find({
'identifier': '1',
})
serialized_results = [json.dumps(result, default=json_util.default, separators=(',', ':')) for result in results]
I've installed pymongo into my Flask virtualenv using pip i.e :
pip install pymongo
When running the above code I keep getting the following error:
ImportError: cannot import name json_util
I can see this line in the pymongo-2.3-py2.6.egg-info/installed-files.txt
../bson/json_util.py
Anyone got any tips that can help me figure out what I'm doing wrong?
UPDATE:
Having noodled about with this a little further - I've managed to get this working thus:
import pymongo
from bson.json_util import dumps
connection = pymongo.Connection("localhost", 27017)
db = connection.mydocs
def get():
cursor = db.foo.find({"name" : "bar"})
return dumps(cursor)
One of the problems I had was trying to pip install bson independently - pymongo brings bson with it and importing bson separately caused problems.
Thanks #Cagex for pointing me in the right direction

Answer 1

It looks like you want to import from bson not pymongo. I believe json_util was moved to that module recently.
https://pymongo.readthedocs.io/en/stable/api/bson/json_util.html

Answer 2

I've seen quite a few posts on this issue but they didn't resolve the issue for me. What worked for me was using dumps(), then loads():
import pymongo
from bson.json_util import dumps
from bson.json_util import loads
connection = pymongo.Connection("localhost", 27017)
db = connection.mydocs
def get():
cursor = db.foo.find({"name" : "bar"})
return loads(dumps(cursor))

Answer 3

you can use list() to convert pymongo cursor to json object.
import pymongo
from bson.json_util import dumps
from bson.json_util import loads
connection = pymongo.Connection("localhost", 27017)
db = connection.mydocs
def get():
cursor = list(db.foo.find({"name" : "bar"}))
return loads(dumps(cursor))

Answer 4

You first need define your own JSONEncoder:
import json
from datetime import datetime
from typing import Any
from bson import ObjectId
class MongoJSONEncoder(json.JSONEncoder):
def default(self, o: Any) -> Any:
if isinstance(o, ObjectId):
return str(o)
if isinstance(o, datetime):
return str(o)
return json.JSONEncoder.default(self, o)
And then use it to encode the Mongo cursor:
data_json = MongoJSONEncoder().encode(list(cursor))
that you can then load as a Python object with json.loads():
data_obj = json.loads(data_json)