Move setting definitions into code (rather than database).

For a setting to be useful, the code has to be able to make sense of it anyway. For this reason it makes sense, that the available settings are defined within the code, rather than in the database, where a missing row has previously caused problems. Instead, settings are now written to the database, when they are changed.

So instead of relying on the database initialization process to create all available settings for us in the database, the supported settings and their defaults are now in a `defaults` dict in the Setting class. With this in place, we can stop populating the `setting` table as a part of database initialization and it will be much easier to support new settings in the future (we no longer need to do anything to the database, to achieve that).

Another benefit is that any changes to default values will take effect automatically, unless the admin has already modified that setting to his/her liking.

To make it easier to get the value of a setting, falling back to defaults etc, a new function `get` has been added to the Setting class. Call it as `Setting().get('setting_name'), and it will take care of returning a setting from the database or return the default value for that setting, if nothing was found.

The `get` function returns `None`, if the setting passed to the function, does not exist in the `Setting.defaults` dict - Indicating that we don't know of a setting by that name.

app/models.py

@@ -884,8 +884,7 @@ class Domain(db.Model):
         domain_obj = Domain.query.filter(Domain.name == domain_name).first()
         domain_auto_ptr = DomainSetting.query.filter(DomainSetting.domain == domain_obj).filter(DomainSetting.setting == 'auto_ptr').first()
         domain_auto_ptr = strtobool(domain_auto_ptr.value) if domain_auto_ptr else False
-        system_auto_ptr = Setting.query.filter(Setting.name == 'auto_ptr').first()
-        system_auto_ptr = strtobool(system_auto_ptr.value)
+        system_auto_ptr = strtobool(Setting().get('auto_ptr'))
         self.name = domain_name
         domain_id = self.get_id_by_name(domain_reverse_name)
         if None == domain_id and \
@@ -1468,8 +1467,7 @@ class Record(object):
         domain_auto_ptr = DomainSetting.query.filter(DomainSetting.domain == domain_obj).filter(DomainSetting.setting == 'auto_ptr').first()
         domain_auto_ptr = strtobool(domain_auto_ptr.value) if domain_auto_ptr else False
 
-        system_auto_ptr = Setting.query.filter(Setting.name == 'auto_ptr').first()
-        system_auto_ptr = strtobool(system_auto_ptr.value)
+        system_auto_ptr = strtobool(Setting().get('auto_ptr'))
 
         if system_auto_ptr or domain_auto_ptr:
             try:
@@ -1710,6 +1708,18 @@ class Setting(db.Model):
     name = db.Column(db.String(64))
     value = db.Column(db.String(256))
 
+    # default settings (serves as list of known settings too):
+    # Note: booleans must be strings because of the way they are stored and used
+    defaults = {
+        'maintenance': 'False',
+        'fullscreen_layout': 'True',
+        'record_helper': 'True',
+        'login_ldap_first': 'True',
+        'default_record_table_size': 15,
+        'default_domain_table_size': 10,
+        'auto_ptr': 'False'
+    }
+
     def __init__(self, id=None, name=None, value=None):
         self.id = id
         self.name = name
@@ -1722,42 +1732,41 @@ class Setting(db.Model):
         self.value = value
 
     def set_mainteance(self, mode):
-        """
-        mode = True/False
-        """
-        mode = str(mode)
         maintenance = Setting.query.filter(Setting.name=='maintenance').first()
+
+        if maintenance is None:
+            value = self.defaults['maintenance']
+            maintenance = Setting(name='maintenance', value=value)
+            db.session.add(maintenance)
+
+        mode = str(mode)
+
         try:
-            if maintenance:
-                if maintenance.value != mode:
-                    maintenance.value = mode
-                    db.session.commit()
-                return True
-            else:
-                s = Setting(name='maintenance', value=mode)
-                db.session.add(s)
+            if maintenance.value != mode:
+                maintenance.value = mode
                 db.session.commit()
-                return True
+            return True
         except:
             logging.error('Cannot set maintenance to {0}'.format(mode))
-            logging.debug(traceback.format_exc())
+            logging.debug(traceback.format_exec())
             db.session.rollback()
             return False
 
     def toggle(self, setting):
-        setting = str(setting)
         current_setting = Setting.query.filter(Setting.name==setting).first()
+
+        if current_setting is None:
+            value = self.defaults[setting]
+            current_setting = Setting(name=setting, value=value)
+            db.session.add(current_setting)
+
         try:
-            if current_setting:
-                if current_setting.value == "True":
-                    current_setting.value = "False"
-                else:
-                    current_setting.value = "True"
-                db.session.commit()
-                return True
+            if current_setting.value == "True":
+                current_setting.value = "False"
             else:
-                logging.error('Setting {0} does not exist'.format(setting))
-                return False
+                current_setting.value = "True"
+            db.session.commit()
+            return True
         except:
             logging.error('Cannot toggle setting {0}'.format(setting))
             logging.debug(traceback.format_exec())
@@ -1765,23 +1774,34 @@ class Setting(db.Model):
             return False
 
     def set(self, setting, value):
-        setting = str(setting)
-        new_value = str(value)
         current_setting = Setting.query.filter(Setting.name==setting).first()
+
+        if current_setting is None:
+            current_setting = Setting(name=setting, value=None)
+            db.session.add(current_setting)
+
+        value = str(value)
+
         try:
-            if current_setting:
-                current_setting.value = new_value
-                db.session.commit()
-                return True
-            else:
-                logging.error('Setting {0} does not exist'.format(setting))
-                return False
+            current_setting.value = value
+            db.session.commit()
+            return True
         except:
             logging.error('Cannot edit setting {0}'.format(setting))
             logging.debug(traceback.format_exec())
             db.session.rollback()
             return False
 
+    def get(self, setting):
+        if setting in self.defaults:
+            result = self.query.filter(Setting.name == setting).first()
+            if result is not None:
+                return result.value
+            else:
+                return self.defaults[setting]
+        else:
+            logging.error('Unknown setting queried: {0}'.format(setting))
+
 
 class DomainTemplate(db.Model):
     __tablename__ = "domain_template"