user preferences: use JSON type for 'value' column, no need for _valu…

…e column+properties. Added 'preferences' backref to User model

abilian/services/preferences/models.py

@@ -1,39 +1,31 @@
 """
 Models for user preferences.
 """
-import json
+from __future__ import absolute_import
 
-from sqlalchemy import Column, Integer, String, ForeignKey, Unicode
-from sqlalchemy.orm import relation
+from sqlalchemy import Column, Integer, String, ForeignKey, UniqueConstraint
+from sqlalchemy.orm import relation, backref
 
 from abilian.core.extensions import db
 from abilian.core.subjects import User
-
+from abilian.core.sqlalchemy import JSON
 
 class UserPreference(db.Model):
   """An atom of user preference."""
-
   __tablename__ = 'user_preference'
+  __table_args__ = (UniqueConstraint('user_id', 'key'),)
 
   #: Unique id for this preference.
   id = Column(Integer, primary_key=True, autoincrement=True)
 
   #: The user who set this preference.
-  user = relation(User)
+  user = relation(
+    User, backref=backref('preferences', cascade="all, delete, delete-orphan")
+  )
   user_id = Column(ForeignKey(User.id))
 
   #: The key
   key = Column(String, nullable=False)
 
   #: The value
-  _value = Column(Unicode, nullable=False)
-
-  @property
-  def value(self):
-    return json.loads(self._value)
-
-  @value.setter
-  def value(self, value):
-    self._value = unicode(json.dumps(value))
-
-  # TODO: use JSON to serialize values?
+  value = Column(JSON, nullable=False)

abilian/services/preferences/service.py

@@ -37,17 +37,15 @@ def get_preferences(self, user=None):
     """
     if user is None:
       user = current_user
-    preferences = UserPreference.query.filter(UserPreference.user_id == user.id).all()
-    return { pref.key: pref.value for pref in preferences}
+    return { pref.key: pref.value for pref in user.preferences }
 
   def set_preferences(self, user=None, **kwargs):
     """Sets preferences from keyword arguments.
     """
     if user is None:
       user = current_user
 
-    preferences = UserPreference.query.filter(UserPreference.user_id == user.id).all()
-    d = { pref.key: pref for pref in preferences}
+    d = { pref.key: pref for pref in user.preferences }
     for k, v in kwargs.items():
       if k in d:
         d[k].value = v
@@ -61,9 +59,10 @@ def clear_preferences(self, user=None):
     if user is None:
       user = current_user
 
-    preferences = UserPreference.query.filter(UserPreference.user_id == user.id).all()
-    for pref in preferences:
-      db.session.delete(pref)
+    #  don't delete UserPreference 1 by 1 with session.delete, else
+    #  user.preferences is not updated until commit() (not flush()). see
+    #  http://docs.sqlalchemy.org/en/rel_0_7/orm/session.html#deleting-from-collections
+    user.preferences = []
 
   def register_panel(self, panel):
     self.panels.append(panel)

abilian/services/preferences/tests.py

@@ -2,12 +2,13 @@
 from abilian.testing import BaseTestCase
 
 from .service import PreferenceService
-
+from .models import UserPreference
 
 class PreferencesTestCase(BaseTestCase):
 
   def test_preferences(self):
     user = User(email=u"test@example.com")
+    assert UserPreference.query.all() == []
 
     preference_service = PreferenceService()
 
@@ -25,6 +26,7 @@ def test_preferences(self):
 
     preferences = preference_service.get_preferences(user)
     self.assertEquals(preferences, {})
+    assert UserPreference.query.all() == []
 
   def test_preferences_with_various_types(self):
     user = User(email=u"test@example.com")