Скачать или смотреть Setting Class Variables in Python: Using Private Static Methods the right way

Learn how to set class variables in Python using private static methods by effectively utilizing decorators and class methods.
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This video is based on the question https://stackoverflow.com/q/70017531/ asked by the user 'Shlomi Schwartz' ( https://stackoverflow.com/u/1115237/ ) and on the answer https://stackoverflow.com/a/70018042/ provided by the user 'Shanavas M' ( https://stackoverflow.com/u/4247851/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Setting Class Variables in Python: Using Private Static Methods the Right Way

When working with class variables in Python, especially within the context of abstract base classes, developers often encounter challenges. One common issue arises when you need to set a class variable from within a private static method. In this guide, we will explore how to effectively set class variables in a Python base class using decorators and class methods.

The Problem

Consider the following scenario where you have created a base static class in Python:

[[See Video to Reveal this Text or Code Snippet]]

In this example, you want to set the credentials class variable from within the __init_session private method, which is triggered by a decorator whenever the process method is called. However, this does not work as intended, and you find yourself stuck.

The Solution

To achieve your goal of setting the credentials variable from the private method, you can utilize a few strategies. Here’s how you can restructure your code to effectively set the class variable.

Step-by-Step Implementation

Change the Decorator: Modify the __init_session method to accept the class (cls) and the path as arguments.

Use cls to Set the Class Variable: Within this method, you can set the credentials variable directly using the class reference.

Update the Process Method: Change the process method to be a @ classmethod, so it has access to the class object.

Here’s the revised code:

[[See Video to Reveal this Text or Code Snippet]]

Key Changes Explained

Static Method to Inner Function: The __init_session is now a static method that returns an inner function. This inner function takes both the class (cls) and the calling path as parameters.

Setting Class Variables: Inside the inner function, cls.credentials allows you to set the class variable.

Decorator Usage: The process method is decorated with @ __init_session, ensuring that class credentials gets set before any further processing.

Conclusion

By following these steps, you can not only set class variables from within private static methods but do so in a clean and understandable way. This approach leverages the power of class methods and decorators, making your code more maintainable and successful in meeting your objectives.

Give this method a try in your own projects, and enjoy the power of flexibility in Python class designs!