PyHooks

PyHooks is meant to expose method hook for classes

Status

This project is maintained, feel free to open issues or pull requests.

Purpose

Have you ever wanted to execute code before or after a method ? PyHooks solve this exact problem taking inspiration from marshmallow's hook system.

Installation

Like any other published python package, you can install it via pip :

pip install pyhooks

How to use ?

To use it, you first need to implement a hooked method. You do this by decorating the method with @Hook.

For example, suppose you have a class that at some moment save your data (such as a database). If you want to be able to plug new behavior, your code will look like this:

from pyhooks import Hook


class DatabaseEntry(object):
    @Hook
    def save(self):
        pass # save implementation here

Thanks to the @Hook line, you will now be able to add functions that execute before and after the save method using the decorators @precall_register and @postcall_register.

For instance, if you want to increment a version variable before saving, you could do:

from pyhooks import precall_register


class VersionnedEntry(DatabaseEntry):
    @precall_register("save")
    def increment_version(self):
        self.version += 1

The decorator directive indicates to your class that increment_version should be run before the save method that is passed to the decorator as argument.

Examples

You can find some more examples in the examples/ directory of this repository.

Advanced usage

You can specialize a register decorator by calling it outside of a decorator context. The last example would yield:

from pyhooks import precall_register

pre_save = precall_register("save")


class VersionnedEntry(DatabaseEntry):
    @pre_save
    def increment_version(self):
        self.version += 1