mitsuhiko/flask — pull request #775 by Xion (2013-06-22 20:17:07+00:00)
Title: Add Flask.config_class attribute

Similar to ``request_class``, ``response_class`` and ``app_ctx_globals_class``, the ``config_class`` attribute of ``Flask`` allows to specify custom class that stores the configuration for the app:

```python
import flask

class Config(flask.Config):
def __getitem__(self, key):
try:
return super(Config, self).__getitem__(key)
except KeyError:
return None

class Flask(flask.Flask):
config_class = Config
```

The current alternative is to override ``make_config`` and repeat its logic (such as handling of ``instance_relative`` argument). This should be more convenient and robust.