Hi,
I'm working on a slightly large application and I'm trying to model it as a
some kind of plugin architecture so that it modular and I can enable or
take out features without lot of code changes.
One of the issues I faced was that the wanted to add some methods to a
class only when a feature/plugin is enabled.
Here is a simplified version of what I have:
class Place(Mixable):
def __init__(self, name):
self.name = name
def get_users(self):
return "users-of-{}".format(self.name)
def get_links(self):
return "links-of-{}".format(self.name)
There are couple of issues with this.
1. The logic for computing users or links doesn't really belong to this
file. I wanted to that in a separate module for modularity.
2. The Place class will become too large to manage over time.
So, I came up with the following approach to address these issues.
# place.py
class Mixable(object):
"""Magic class to allow adding mixins to the class at run-time.
"""
@classmethod
def mixin(cls, mixin):
"""Decorator to add a mixin to the class runtime.
"""
cls.__bases__ = cls.__bases__ + (mixin,)
class Place(Mixable):
def __init__(self, name):
self.name = name
# users.py
@Place.mixin
class UsersMixin(object):
def get_users(self):
return "users-of-{}".format(self.name)
# links.py
@Place.mixin
class LinksMixin(object):
def get_links(self):
return "links-of-{}".format(self.name)
p = Place('bangalore')
print(p.get_users())
print(p.get_links())
With this I was able to split the class into 3 files and now I have
flexibility of deciding which features enable from a config file.
What do you guys think of this approach?
Is this a good practice?
Are there any know flaws in this approach?
How did you solve that issue when you faced similar situation?
Anand
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