Alohomora: unlocking the magical bits in python

speaker: Prashant Sinha, University of Delhi event: FOSSASIA 2017

Decorator is a function that accepts a function and returns a function

Usage

• add debug logging to functions

Decorator with parameter, needs to return a decorator

Monkey patching

• change an existing binding

unittest.mock provides helpers for patching

• @patch(‘requests.api.request’, req_cached)

Restrict using of certain functions, eg eval

• builtin.eval = eval_nope

Metaclass

• classes are objects of type type
• a metaclass creates a class
• type is a metaclass used to create the standard classes
• type(name, bases, dict) generates a new class

Metaclass extends type to control how classes are defined

• rename the attributes of a class