Python bson.errors.InvalidDocument: Unable to encode object: datetime.date (2015, 3, 1)

Question

I have the following functions:

#  this is in a module called 'dbw_lib'
def dateTimeOuput(start_days_back, end_days_back):
    start_delta = datetime.timedelta(days=start_days_back)
    end_delta = datetime.timedelta(days=end_days_back)
    start_date = datetime.date.today() - start_delta
    end_date = datetime.date.today() - end_delta
    return start_date, end_date

def dictByDate(start_days, end_days):
    start_date, end_date = dbw_lib.dateTimeOuput(start_days, end_days)

    date_string = { "created_at": {"$gte" : start_date, "$lt": end_date }  }

    user_id_email_dict = dbw_lib.dbwIdToEmailD(user_coll_obj, date_query = date_string)  # dict of all user ids and emails  
    print user_id_email_dict
    quit()

when I start key_dicts = dictByDate(90, 60), I get the following trace:

Traceback (most recent call last):
File "main.py", line 212, in <module>
program.runProgram()
File "main.py", line 61, in runProgram
report.RcreateReport()
File "filepath/report.py", line 86, in RcreateReport
key_dicts = dictByDate(90, 60)
File "filepath/report.py", line 65, in dictByDate
user_id_email_dict = dbw_lib.dbwIdToEmailD(user_coll_obj, date_query = date_string)  # dict of all user ids and emails  
File "filepath/dbw_lib.py", line 50, in dbwIdToEmailD
for pair in id_email_cursor:
File "/Library/Python/2.7/site-packages/pymongo-3.0-py2.7-macosx-10.9-intel.egg/pymongo/cursor.py", line 968, in __next__
File "/Library/Python/2.7/site-packages/pymongo-3.0-py2.7-macosx-10.9-intel.egg/pymongo/cursor.py", line 905, in _refresh
File "/Library/Python/2.7/site-packages/pymongo-3.0-py2.7-macosx-10.9-intel.egg/pymongo/cursor.py", line 812, in __send_message
File "/Library/Python/2.7/site-packages/pymongo-3.0-py2.7-macosx-10.9-intel.egg/pymongo/mongo_client.py", line 732, in _send_message_with_response
File "/Library/Python/2.7/site-packages/pymongo-3.0-py2.7-macosx-10.9-intel.egg/pymongo/mongo_client.py", line 743, in _reset_on_error
File "/Library/Python/2.7/site-packages/pymongo-3.0-py2.7-macosx-10.9-intel.egg/pymongo/server.py", line 85, in send_message_with_response
File "/Library/Python/2.7/site-packages/pymongo-3.0-py2.7-macosx-10.9-intel.egg/pymongo/message.py", line 107, in get_message
bson.errors.InvalidDocument: Cannot encode object: datetime.date(2015, 3, 1)

Answer 1

just replace

datetime.date.today()

with

datetime.datetime.today()

Answer 2

datetime.datenot part of bson coding codes. (Perhaps the authors forgot about this or left it intentionally, since it is ambiguous to add time information to date exactly like that.)

But you can write a function to extend custom types in pymongo. Just as you increase JSONEncoderin json, you can do something similar in pymongo using SONManipulator:

import datetime
import pymongo

class MigrationTransformer(pymongo.son_manipulator.SONManipulator):

    def _encode_date(self, value):
        return datetime.datetime.combine(
                value,
                datetime.datetime.min.time())

    def transform_incoming(self, son, collection):
        for (key, value) in son.items():
            # datetime.datetime is instance of datetime.date
            # compare type explicitly only
            if type(value) == datetime.date:
                son[key] = self._encode_date(value)
            elif isinstance(value, dict):    # recurse into sub-docs
                son[key] = self.transform_incoming(value, collection)
        return son

DB:

db.add_son_manipulator(MigrationTransformer())

( transform_outgoing, , : http://api.mongodb.org/python/current/examples/custom_type.html)

. , dict . - pymongo SONManipulator. , .

, ( sets tuples).

class MigrationTransformer(SONManipulator):

    def _encode_date(self, value):
        return datetime.datetime.combine(
                value,
                datetime.datetime.min.time())

    def _handle_list(self, value):
        for index, item in enumerate(value):
            if isinstance(item, dict):
                value[index] = self._handle_dict(item)
            elif isinstance(item, list):
                value[index] = self._handle_list(item)
            elif isinstance(item, datetime.date):
                value[index] = self._encode_date(item)
        return value

    def _handle_dict(self, item):
        for (key, value) in item.items():
            if type(value) == datetime.date:
                item[key] = self._encode_date(value)
            elif isinstance(value, dict):    # recurse into sub-docs
                item[key] = self._handle_dict(value)
            elif isinstance(value, list):    # recurse into sub-docs
                item[key] = self._handle_list(value)
        return item

    def transform_incoming(self, son, collection):
        for (key, value) in son.items():
            # datetime.datetime is instance of datetime.date
            # compare type explicitly only
            if type(value) == datetime.date:
                son[key] = self._encode_date(value)
            elif isinstance(value, dict):    # recurse into sub-docs
                son[key] = self.transform_incoming(value, collection)
            elif isinstance(value, list):    # recurse into sub-docs
                son[key] = self._handle_list(value)
        return son

Answer 3

,

PyMongo . , , . , datetime, .

.

, datetime.datetime.combine:

datetime.datetime.combine(dateWithoutTime, datetime.time.min)