Python simple plugin system prototype

記錄一下之前用 Python 實現的一個簡單 Plugin 原型.
想實現類 WordPress 的結構.
更完整的版本還在實現中請留意 Github 上存檔.
目前這版本用的是 class method 實現感覺不太好.

> python test.py

Content: This is test message
Encoded: VGhpcyBpcyB0ZXN0IG1lc3NhZ2U=
Decoded: This is test message

Path: ./test.py

#!/usr/bin/env python
#coding: utf-8

from os.path import join, abspath, dirname
from plugin import Plugin

def main():
    Plugin.folder(join(abspath(dirname(__file__)), 'plugins'))
	
    content = 'This is test message'
    encoded = Plugin.apply_filter('encode', content)
    decoded = Plugin.apply_filter('decode', encoded)
	
    Plugin.do_action('result', dict(
        content = content,
        encoded = encoded,
        decoded = decoded,	
    ))

if __name__ == "__main__":
    main()

Path: ./plugin.py

#!/usr/bin/env python
#coding: utf-8

import os
import imp
import sys

class Plugin(object):

    filters  = {}
    actions  = {}

    @classmethod
    def folder(cls, path, module_name='pp.plugins'):
        root_path = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))

        parent_module = imp.new_module(module_name)
        sys.modules[module_name] = parent_module

        for folder_path, folder_names, filenames in os.walk(path):
            for filename in filenames:
                if filename.endswith('.py'):
                    file_path   = os.path.join(folder_path, filename)
                    source_name = "{0}.{1}".format(module_name, filename.replace('.py', ''))
                    
                    imp.load_source(source_name, file_path)

    @classmethod
    def add_filter(cls, name, method):
        cls.filters[name] = method

    @classmethod
    def apply_filter(cls, name, value):
        filter = cls.filters.get(name)

        if not filter:
            raise ValueError('Can not found filter named: {0}'.format(name))
        else:
            return filter(value)

    @classmethod
    def add_action(cls, name, method):
        cls.actions[name] = method

    @classmethod
    def do_action(cls, name, value):
        action = cls.actions.get(name)

        if not action:
            raise ValueError('Can not found action named: {0}'.format(name))
        else:
            action(value)

Path: ./plugins/hello/secret.py

from base64 import b64decode, b64encode
from plugin import Plugin

# Filter
def encode(content):
	return b64encode(content)

def decode(content):
	return b64decode(content)

Plugin.add_filter('encode', encode)	
Plugin.add_filter('decode', decode)

# Action
def result(results):
	print("Content: {0}".format(results.get('content')))
	print("Encoded: {0}".format(results.get('encoded')))
	print("Decoded: {0}".format(results.get('decoded')))
	
Plugin.add_action('result', result)