####### PyHooks #######

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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 :

.. code-block:: bash

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:

.. code-block:: python

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:

.. code-block:: python

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:

.. code-block:: python

from pyhooks import precall_register

pre_save = precall_register("save")


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