Question

我有以下功能：

#  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()

当我运行key_dicts = dictByDate(90, 60)时，我得到以下追溯：

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

只需替换

datetime.date.today()

与

datetime.datetime.today()

Answer 2

原来那个

PyMongo不支持保存日期实例。服务器没有没有时间的日期类型，所以必须有一些用于保存日期的惯例。如果你需要保存一个您的客户应该将其转换为日期时间实例的日期，您可以除此之外。

Quote's source

This answer声明可以使用datetime.datetime.combine方法完成此操作：

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

Answer 3

datetime.date不是bson编码器的一部分。（也许作者忘记了它或者故意将它遗漏掉了，因为它模糊地将时间信息附加到日期那样。）

但您可以编写一个函数来扩展 pymongo 中的自定义类型就像你如何在JSONEncoder中扩展json一样，你可以使用SONManipulator在pymongo中做类似的事情：

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

然后将其附加到您的数据库实例：

db.add_son_manipulator(MigrationTransformer())

（我没有提供transform_outgoing方法，因为这与问题无关，但你可以在这里找到它：http://api.mongodb.org/python/current/examples/custom_type.html）

编辑：如果dict中的键值是列表类型，则会出现问题。出于某种原因，pymongo没有将它传递给SONManipulator。因此列表不会被转换。

我已更新课程以处理此问题（但我没有为sets和tuples执行此操作。

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

python bson.errors.InvalidDocument：无法编码对象：datetime.date（2015,3,1）

3 个答案: