Скачать или смотреть Enabling CORS for Any Port on localhost and Specific Domains in ASP.NET Core 6.0

A detailed guide on how to enable CORS in ASP.NET Core 6.0 for localhost and specific domains, ensuring smooth communication in web applications.
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Enabling CORS in ASP.NET Core 6.0

CORS, or Cross-Origin Resource Sharing, is an essential feature for modern web applications that allows resources to be requested from another domain outside the domain from which the first resource was served. If you are developing applications using ASP.NET Core 6.0, you might want to enable CORS for your localhost and some specific domains. In this guide, we will walk you through how to achieve this effectively.

Why Enable CORS?

The Need for CORS

When you are developing a web application with separate front-end and back-end servers, you might find that the front-end is running on localhost:3000 while your API is on localhost:5000. In such scenarios, if your front-end attempts to make requests to the back-end API, the browser's Same-Origin Policy will block these requests by default. Enabling CORS allows browsers to make requests across different domains, thus facilitating smoother development and user experience.

How to Enable CORS in ASP.NET Core 6.0

Step 1: Configure CORS Policies

To enable CORS in your ASP.NET Core application, you need to define specific policies in the Startup class. Below is a code snippet that demonstrates how to set this up:

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

Step 2: Understanding the Code

In the code snippet above:

Adding CORS Policies: Two policies have been defined:

NonDevCorsPolicy for specific domains (i.e., allowing requests from subdomains of companydomain.com).

DevCorsPolicy for local development. This policy allows requests from localhost and any custom local domains like myweb.local.

Using CORS Middleware: The app.UseCors(); middleware needs to be placed in the Configure method to apply the configured CORS policies throughout the application.

Step 3: Testing the Implementation

To ensure that CORS is set up correctly:

Launch your application and try making requests from your front-end running on localhost.

Verify that requests from the specified domains return successfully without any CORS-related errors in the browser console.

Conclusion

Enabling CORS for any port on localhost, as well as specific domains in ASP.NET Core 6.0, is a straightforward process. By defining appropriate policies and using middleware, you can ensure that your back-end services are accessible during development and deployment. Implementing these CORS policies will help streamline your development process, enhance interoperability, and ensure that your web app runs smoothly across different environments.

For more detailed guidance on managing CORS, feel free to check out the official ASP.NET Core documentation or follow along with industry blogs that dive deeper into the topic. Enable CORS wisely, and your applications will communicate seamlessly!