"""
MDSuite: A Zincwarecode package.
License
-------
This program and the accompanying materials are made available under the terms
of the Eclipse Public License v2.0 which accompanies this distribution, and is
available at https://www.eclipse.org/legal/epl-v20.html
SPDX-License-Identifier: EPL-2.0
Copyright Contributors to the Zincwarecode Project.
Contact Information
-------------------
email: zincwarecode@gmail.com
github: https://github.com/zincware
web: https://zincwarecode.com/
Citation
--------
If you use this module please cite us with:
Summary
-------
"""
import json
from sqlalchemy.ext.mutable import Mutable
from sqlalchemy.types import VARCHAR, TypeDecorator
[docs]class JSONEncodedDict(TypeDecorator):
"""Represents an immutable structure as a json-encoded string."""
impl = VARCHAR
[docs] def process_bind_param(self, value: dict, dialect):
"""Provide a bound value processing function.
Convert a dictionary to a json string and store the string in the database
"""
if value is not None:
value = json.dumps(value)
return value
[docs] def process_result_value(self, value, dialect) -> dict:
"""Receive a result-row column value to be converted.
Convert a loaded string from the database into a dict object
"""
if value is not None:
value = json.loads(value)
return value
[docs]class MutableDict(Mutable, dict):
"""Subclassed version of a dictionary used in the database."""
[docs] @classmethod
def coerce(cls, key, value):
"""Convert plain dictionaries to MutableDict."""
if not isinstance(value, MutableDict):
if isinstance(value, dict):
return MutableDict(value)
# this call will raise ValueError
return Mutable.coerce(key, value)
else:
return value
def __setitem__(self, key, value):
"""Detect dictionary set events and emit change events."""
dict.__setitem__(self, key, value)
self.changed()
def __delitem__(self, key):
"""Detect dictionary del events and emit change events."""
dict.__delitem__(self, key)
self.changed()