flatisfy/migrations/versions/d21933db9ad8_add_flat_posit...

70 lines
1.9 KiB
Python

"""Add flat position column
Revision ID: d21933db9ad8
Revises: 8155b83242eb
Create Date: 2021-02-08 16:26:37.190842
"""
from alembic import op
import sqlalchemy as sa
import sqlalchemy.types as types
import json
class StringyJSON(types.TypeDecorator):
"""
Stores and retrieves JSON as TEXT for SQLite.
From
https://avacariu.me/articles/2016/compiling-json-as-text-for-sqlite-with-sqlalchemy.
.. note ::
The associated field is immutable. That is, changes to the data
(typically, changing the value of a dict field) will not trigger an
update on the SQL side upon ``commit`` as the reference to the object
will not have been updated. One should force the update by forcing an
update of the reference (by performing a ``copy`` operation on the dict
for instance).
"""
impl = types.TEXT
def process_bind_param(self, value, dialect):
"""
Process the bound param, serialize the object to JSON before saving
into database.
"""
if value is not None:
value = json.dumps(value)
return value
def process_result_value(self, value, dialect):
"""
Process the value fetched from the database, deserialize the JSON
string before returning the object.
"""
if value is not None:
value = json.loads(value)
return value
# TypeEngine.with_variant says "use StringyJSON instead when
# connecting to 'sqlite'"
# pylint: disable=locally-disabled,invalid-name
MagicJSON = types.JSON().with_variant(StringyJSON, "sqlite")
# revision identifiers, used by Alembic.
revision = "d21933db9ad8"
down_revision = "8155b83242eb"
branch_labels = None
depends_on = None
def upgrade():
op.add_column("flats", sa.Column("flatisfy_position", MagicJSON, default=False))
def downgrade():
op.drop_column("flats", "flatisfy_position")