如何扩展python模块?向`python-twitter` 包添加新功能 [英] How do I extend a python module? Adding new functionality to the `python-twitter` package

问题描述

扩展现有 Python 模块的最佳实践是什么?在本例中，我想通过向基本 API 类添加新方法来扩展 python-twitter 包.

What are the best practices for extending an existing Python module – in this case, I want to extend the python-twitter package by adding new methods to the base API class.

我看过tweepy，我也喜欢它；我只是发现 python-twitter 更容易理解和扩展我想要的功能.

I've looked at tweepy, and I like that as well; I just find python-twitter easier to understand and extend with the functionality I want.

我已经编写了这些方法——我正在尝试找出最 Python 化和破坏性最小的方法，将它们添加到 python-twitter 包模块中，而无需更改该模块的核心.

I have the methods written already – I'm trying to figure out the most Pythonic and least disruptive way to add them into the python-twitter package module, without changing this modules’ core.

推荐答案

几种方法.

简单的方法:

不要扩展模块，扩展类.

Don't extend the module, extend the classes.

exttwitter.py

exttwitter.py

import twitter

class Api(twitter.Api):
    pass 
    # override/add any functions here.

缺点:twitter 中的每个类都必须在 exttwitter.py 中，即使它只是一个存根(如上所述)

Downside : Every class in twitter must be in exttwitter.py, even if it's just a stub (as above)

更难(可能不是 Pythonic)的方法:

将 * 从 python-twitter 导入到一个模块中，然后再进行扩展.

Import * from python-twitter into a module that you then extend.

例如:

basemodule.py

basemodule.py

 class Ball():
    def __init__(self,a):
        self.a=a
    def __repr__(self):
        return "Ball(%s)" % self.a

def makeBall(a):
    return Ball(a)

def override():
    print "OVERRIDE ONE"

def dontoverride():
    print "THIS WILL BE PRESERVED"

extmodule.py

extmodule.py

from basemodule import *
import basemodule

def makeBalls(a,b):
    foo = makeBall(a)
    bar = makeBall(b)
    print foo,bar

def override():
    print "OVERRIDE TWO"

def dontoverride():
    basemodule.dontoverride()
    print "THIS WAS PRESERVED"

runscript.py

runscript.py

import extmodule

#code is in extended module
print extmodule.makeBalls(1,2)
#returns Ball(1) Ball(2)

#code is in base module
print extmodule.makeBall(1)
#returns Ball(1)

#function from extended module overwrites base module
extmodule.override()
#returns OVERRIDE TWO

#function from extended module calls base module first
extmodule.dontoverride()
#returns THIS WILL BE PRESERVED
THIS WAS PRESERVED

我不确定 extmodule.py 中的双重导入是否是 pythonic - 您可以将其删除，但是您无法处理想要扩展 basemodule 命名空间中的函数的用例.

I'm not sure if the double import in extmodule.py is pythonic - you could remove it, but then you don't handle the usecase of wanting to extend a function that was in the namespace of basemodule.

至于扩展类，只需创建一个新的 API(basemodule.API) 类来扩展 Twitter API 模块.

As far as extended classes, just create a new API(basemodule.API) class to extend the Twitter API module.

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