Marshmallow: Schema design question?

[rlam3]

Is there a way to pass current_user object from flask app to schema to be used to determine a Boolean.

Currently I have a couple of tables:

Tables/Relations:

user_table
subscription_table
  -foreignkey to user_table as user_id
  -foreignkey to game_table as game_id
game_table
  - backref to subscription_table as subscription
  - is_subscribed is a property that returns a Bool if user has a subscription to current game_table

from flask import current_user

class Game(db.Model):
    ...
    @property
    def isSubscribed(user=None):
        return current_user.is_subscribed_to_current_game()
    ...

I want to be able to extract game_table data with a schema. But how can I pass a user_id from my request to the schema to be used to see if user is currently subscribed to a game_table?

OR Another approach is:

How can I append another element/dict element to the already dumped result?

{
'data':[
{
    'id' :1,
    'name': 'some_name',
    'isSubscribed': false, <<<<< How do I append a boolean from request to the already dumped schema? 
},...
]
}

Thanks! I'm really new to marshmallow.

[maximkulkin]

1. You example won't work, because properties can't have arguments.
2. You can pass user_id into schema via context:

class GameSchema(marshmallow.Schema):
    is_subscribed = marshmallow.fields.Method('get_subscribed')

    def get_subscribed(self, game):
        return game.user_id == self.context.get('user_id')

schema = GameSchema()
schema.context['user_id'] = flask.current_user
schema.dump(game)

Also, it is possible to update dumped result afterwards:

games_data = GameSchema(many=True).dump(games)
for game_data in games_data:
    game_data['is_subscribed'] = is_user_subscribed_to_game(user_id, game_data['id'])
return games_data

[sloria]

@maximkulkin is correct--either use context or update the data afterwards.

You could even update the context automatically using pre_load:

from marshmallow import Schema, fields, pre_dump

class GameSchema(Schema):
    is_subscribed = fields.Method('get_subscribed')

    def get_subscribed(self, game):
        return game.user_id == self.context['current_user'].id

    @pre_dump
    def set_current_user(self, data):
        self.context['current_user'] = current_user