Add the AppState model

This allows setting application state during run time

calsocial/app_state.py

@@ -0,0 +1,60 @@
+# Calendar.social
+# Copyright (C) 2018  Gergely Polonkai
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+"""Metaclass for storing and accessing app state
+"""
+
+def get_state_base(self, key):
+    """Method to get a key from the state store
+    """
+
+    return self.__get_state__(key)
+
+def set_state_base(self, key, value):
+    """Method to set a key/value in the state store
+    """
+
+    self.__set_state__(key, str(value))
+
+def set_default_base(self, key, value):
+    """Method to set the default value of a key in the state store
+
+    If key is already in the state store, this method is a no-op.
+    """
+
+    self.__set_state_default__(key, str(value))
+
+
+def app_state_base(klass):
+    """Base class creator for AppStateMeta types
+
+    :param klass: the class to extend
+    :type klass: type
+    :returns: a new class extending ``klass``
+    :rtype: type
+    """
+
+    # Construct the meta class based on the metaclass of ``klass``
+    metaclass = type(
+        klass.__name__ + 'BaseMeta',
+        (type(klass),),
+        {
+            '__getitem__': get_state_base,
+            '__setitem__': set_state_base,
+            'setdefault': set_default_base,
+        })
+
+    return metaclass(klass.__name__ + 'Base', (klass,), {'__abstract__': True})

calsocial/models.py

@@ -21,12 +21,14 @@ from datetime import datetime
 from enum import Enum
 from warnings import warn
 
+from flask import current_app
 from flask_babelex import lazy_gettext
 from flask_security import UserMixin, RoleMixin
 from flask_sqlalchemy import SQLAlchemy
 from sqlalchemy.orm.exc import NoResultFound
 from sqlalchemy_utils.types.choice import ChoiceType
 
+from .app_state import app_state_base
 from .cache import cache
 from .utils import force_locale
 
@@ -206,7 +208,6 @@ class User(db.Model, UserMixin):
         If the user didn’t set a time zone yet, the application default is used.
         """
 
-        from flask import current_app
         from pytz import timezone
         from pytz.exceptions import UnknownTimeZoneError
 
@@ -789,3 +790,64 @@ class Response(db.Model):  # pylint: disable=too-few-public-methods
 
     #: The response itself
     response = db.Column(db.Enum(ResponseType), nullable=False)
+
+
+class AppState(app_state_base(db.Model)):  # pylint: disable=too-few-public-methods
+    """Database model for application state values
+    """
+
+    __tablename__ = 'app_state'
+
+    #: The environment that set this key
+    env = db.Column(db.String(length=40), nullable=False, primary_key=True)
+
+    #: The key
+    key = db.Column(db.String(length=80), nullable=False, primary_key=True)
+
+    #: The value of the key
+    value = db.Column(db.Unicode(length=200), nullable=True)
+
+    @classmethod
+    def __get_state__(cls, key):
+        try:
+            record = cls.query \
+                        .filter(cls.env == current_app.env) \
+                        .filter(cls.key == key) \
+                        .one()
+        except NoResultFound:
+            return None
+
+        return record.value
+
+    @classmethod
+    def __set_state__(cls, key, value):
+        try:
+            record = cls.query \
+                        .filter(cls.env == current_app.env) \
+                        .filter(cls.key == key) \
+                        .one()
+        except NoResultFound:
+            record = cls(env=current_app.env, key=key)
+
+        record.value = value
+        db.session.add(record)
+        db.session.commit()
+
+    @classmethod
+    def __set_state_default__(cls, key, value):
+        try:
+            record = cls.query \
+                        .filter(cls.env == current_app.env) \
+                        .filter(cls.key == key) \
+                        .one()
+        except NoResultFound:
+            pass
+        else:
+            return
+
+        record = cls(env=current_app.env, key=key, value=value)
+        db.session.add(record)
+        db.session.commit()
+
+    def __repr__(self):
+        return f'<AppState {self.env}:{self.key}="{self.value}"'

tests/test_app_state.py

@@ -0,0 +1,49 @@
+# Calendar.social
+# Copyright (C) 2018  Gergely Polonkai
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+def test_app_state_set(database):
+    from calsocial.models import db, AppState
+
+    AppState['test'] = 'value'
+
+    state = AppState.query \
+                    .filter(AppState.env == 'testing') \
+                    .filter(AppState.key == 'test') \
+                    .one()
+
+    assert state.value == 'value'
+
+
+def test_app_state_get(database):
+    from calsocial.models import db, AppState
+
+    state = AppState(env='testing', key='test', value='value')
+    db.session.add(state)
+    db.session.commit()
+
+    assert AppState['test'] == 'value'
+
+
+def test_app_state_setdefault(database):
+    from calsocial.models import AppState
+
+    AppState['test'] = 'value'
+    AppState.setdefault('test', 'new value')
+
+    assert AppState['test'] == 'value'
+
+    AppState.setdefault('other_test', 'value')
+    assert AppState['other_test'] == 'value'