Скачать или смотреть Resolving CORS Issues in Nuxt and Flask with JWT Authentication

Learn how to fix `CORS` policy issues when integrating Nuxt.js with Flask for secure APIs using JWT authentication.
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This video is based on the question https://stackoverflow.com/q/65939698/ asked by the user 'Aman Desai' ( https://stackoverflow.com/u/10809821/ ) and on the answer https://stackoverflow.com/a/65941262/ provided by the user 'Aman Desai' ( https://stackoverflow.com/u/10809821/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Introduction

If you've ever encountered issues while working with your Nuxt.js frontend and Flask backend, particularly around CORS (Cross-Origin Resource Sharing), you’re not alone. Developers frequently face frustrating blocks when their browsers deny requests due to CORS policy restrictions. This article outlines why these issues occur and provides a straightforward solution that will help you overcome them when using JWT for authentication.

Understanding the Problem

When attempting to connect a Nuxt.js application with a Flask backend, many developers face the error related to the CORS policy. This issue arises when the browser blocks requests made from one origin to another for security reasons. Some key points to consider:

CORS Policy Enforcement: Browsers enforce CORS to prevent potentially harmful requests from being sent to a different origin.

Error Codes: In this case, the Flask application responds to the OPTIONS request with an unexpected status code, such as 308, which indicates that the request was redirected and not handled properly.

Configuration Attempts: Common configuration attempts usually involve modifying CORS settings in Flask, but these don't always resolve the issue effectively.

Proposed Solution

After troubleshooting, the key solution revolves around how the Flask blueprints are set up. Here’s how to fix the CORS issue:

Step 1: Remove url_prefix

The main problem was traced back to the usage of url_prefix within Flask blueprints. When using CORS, the url_prefix can disrupt the proper handling of preflight requests. Here’s what you need to do:

Remove the url_prefix from the call to register_blueprint. This means you will not define the URL prefix at this point in code.

Instead of:

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Use:

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Step 2: Manually Define Routes

With the url_prefix removed, you need to explicitly specify your routes within the blueprint files:

For example, in your auth blueprint file:

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Similarly, in your url blueprint file, define the endpoint:

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Step 3: Verify CORS Configuration

Ensure you have defined your CORS settings properly. Here’s an example configuration that should work:

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

Conclusion

By following these steps, you should be able to resolve the CORS issues that arise when integrating Nuxt.js with Flask for API interactions using JWT. Remember, debugging CORS can be arduous, but understanding the underlying principles and configurations can make a significant difference in streamlining your development experience.

Feel free to implement these suggestions in your project and enjoy seamless communication between your frontend and backend!