mongoQuery.py

import pymongo
from bson.json_util import dumps, RELAXED_JSON_OPTIONS

HOST =          # Something like 'mongodb://localhost:23333'
DB =            # What's the database of interest?
COLLECTION =    # And the collection?
QUERY =         # The query parameters, very similar to mongo in js, check out the ref below.
OUTPUT =        # The json file will be written into which place?

# That's all you need to fill above.

__IS_FIRST__ = True
__COUNT__ = 0

out_file = open(OUTPUT, 'a+')
client = pymongo.MongoClient(HOST)

print('i Initializing...')
out_file.write('[')

print('i Querying...')
cursors = client[DB][COLLECTION].find(QUERY)

for cursor in cursors:
  __COUNT__ += 1

  print('i Writing result, ' + str(__COUNT__) + '...')

  if not __IS_FIRST__:
    out_file.write(',')

  out_file.write(dumps(cursor, json_options = RELAXED_JSON_OPTIONS))
  __IS_FIRST__ = False

out_file.write(']')

print('i Done.')