Get python class object from string [duplicate]

Answer 1

You want to use the importlib module to handle loading of modules like this, then simply use getattr() to get the classes.

For example, say I have a module, somemodule.py which contains the class Test:

import importlib

cls = "somemodule.Test"
module_name, class_name = cls.split(".")

somemodule = importlib.import_module(module_name)

print(getattr(somemodule, class_name))

Gives me:

<class 'somemodule.Test'>

It's trivial to add in things like packages:

cls = "test.somemodule.Test"
module_name, class_name = cls.rsplit(".", 1)

somemodule = importlib.import_module(module_name)

And it will not import a module/package if it's already been imported, so you can happily do this without keeping track of loading modules:

import importlib

TWO_FACTOR_BACKENDS = (
    'id.backends.AllowToBeDisabled', # Disable this to enforce Two Factor Authentication
    'id.backends.TOTPBackend',
    'id.backends.HOTPBackend',
    #'id.backends.YubikeyBackend',
    #'id.backends.OneTimePadBackend',
    #'id.backends.EmailBackend',
)

backends = [getattr(importlib.import_module(mod), cls) for (mod, cls) in (backend.rsplit(".", 1) for backend in TWO_FACTOR_BACKENDS)]