Intercepts

Intercepts allows you to intercept function calls in Python and handle them in any manner you choose. For example, you can pre-process the inputs to a function, or apply post-processing on its output. Intercepts also allows you to completely replace a function with a custom implementation.

>>> increment(41)
42
>>> intercepts.register(increment, handler)
>>> increment(41)
40
>>> intercepts.unregister(increment)
>>> intercepts.register(increment, handler2)
>>> increment(41)
'The answer is: 42'
>>> intercepts.unregister_all()

Handler functions receive all paramters to the intercepted function call and can access the intercepted function through the variable _.

>>> def handler(num):
...   result = _(num)
...   return num - (result - num)
>>> def handler2(*args, **kwargs):
...   result = _(*args, **kwargs)
...   return f"The answer is: {result}"

The intercepts module also allows intercepting python built-in functions, such as print and sorted. For best results, the intercepts module should be the first module imported.

>>> def print_handler(message):
...     return _(''.join(reversed(message)))
>>> print("Hello world")
Hello world
>>> intercepts.register(print, print_handler)
>>> print("Hello world")
dlrow olleH

Installation

Intercepts requires Python 3.7+ on Linux or Windows and can be installed using pip.

$ pip install intercepts

Or, use pip to install the latest version from the github source.

$ pip install -U git+https://github.com/dlshriver/intercepts.git@main

Documentation

Some documentation is available here.