Injector-enabled Python application microframework

pip install cask==0.1.1



Build status

Cask is Injector-enabled, Python application microframework modelled after Flask.

It's purpose is to make the amount of boilerplate you need to write when developing your application smaller. Here's a simple example:

>>> from cask import Cask
>>> from injector import inject
>>> def configure(binder):
...     binder.bind(str, to='ABC')
>>> @Cask.run_main(modules=[configure])
... @inject(s=str)
... def main(s):
...     print(s)

Cask.run_main (it works both as class and instance method, see below) does the if __name__ == '__main__' check for you. So this

>>> app = Cask()
>>> @app.run_main
... def main():
...     print(111)

is shorter version of

>>> app = Cask()
>>> @app.main
... def main():
...     print(222)
>>> if __name__ == '__main__':


Cask constructor and Cask.run_main class method accept the following optional keyword arguments:

  • modules - iterable of Injector modules, defaults to empty sequence
  • injector- instance of Injector to configure and use, by default new instance will be created for you


Cask instance provides the following decorators allowing you to register hooks (note that you can inject into registered functions):

  • Cask.before_main - should expect no parameters, if non-None value is returned application execution main function won't be executed

  • Cask.after_main - should expect single result parameter and return processed result (modified or not)

  • Cask.exception_handler(ExceptionCLass) - will handle exception raised during the application execution, should expect single argument called e and containing exception value:

    >>> app = Cask()
    >>> @app.exception_handler(Exception)
    ... def handle(e):
    ...     print('got exception %s' % (e,))
    >>> @app.run_main
    ... def main():
    ...     raise Exception(123)
    got exception 123
  • Cask.main - main function should expect no arguments and may return something

You can, of course, register more than one callable for hooks other than main.


Only first matching exception_handler hook will be called, if any.


This is what happens when you run Cask-based application:

  1. Injector is configured using provided modules
  2. before_main hooks are called
  3. If before_main hooks didn't return value different than None, main hook is executed
  4. after_main hooks are called


Copyright (C) 2013 Jakub Stasiak

This source code is licensed under MIT license, see LICENSE file for details.