SQLAlchemy How to load dates with timezone=UTC (dates stored without timezone)

flask-sqlalchemy, python, sqlalchemy

Solution

You want a custom data type, described here: http://docs.sqlalchemy.org/en/rel_0_9/core/types.html#custom-types

Specifically, something like this:

import pytz  # from PyPI

class AwareDateTime(db.TypeDecorator):
    '''Results returned as aware datetimes, not naive ones.
    '''

    impl = db.DateTime

    def process_result_value(self, value, dialect):
        return value.replace(tzinfo=pytz.utc)

Then just make the column like this:

created_on = db.Column(AwareDateTime, default=db.func.now(), nullable=False)

Problem

I have a model with a date column defined as : ``` created_on = db.Column(db.DateTime, default=db.func.now(), nullable=False) ``` The dates comme out with tz_info=None, which is correct, since the dates are stored without timezone info. If I print the date : ``` print(my_object.created_on.isoformat()) ``` I get this format ``` 2014-04-26T17:46:27.353936 ``` I would like to have a UTC timezone indicator, such as : ``` 2014-04-26T17:46:27.353936Z ``` Is there a way to define this behavior in the schema config ? SQLAlchemy has, timezone=Boolean sqlalchemy.types.DateTime(timezone=False) since I want the storage to be without timezone.

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