Скачать или смотреть How to Fix the Blazor Cascading AuthorizeView Policy Issue with Identity Server 4

Discover the solution to the cascading `AuthorizeView` policy not working in `Blazor` when using `Identity Server 4`, including a custom `ClaimsPrincipalFactory` implementation.
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Resolving the Blazor Cascading AuthorizeView Policy Issue with Identity Server 4

As developers working with Blazor and Identity Server 4, we frequently encounter unique challenges in implementing security policies. One such problem is the cascading AuthorizeView policy not functioning as expected, particularly when trying to hide options in navigation menus based on user authorization. In this guide, we'll dive into understanding the issue and guide you through an effective solution.

Understanding the Problem

You may be trying to create a complex navigation structure that relies on cascading AuthorizeView components, similar to the following pattern:

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However, when your application runs, you find that menu items protected by AuthorizeView do not appear, while those not using authorization are visible. This issue often stems from the way claims are being read and processed in your application, especially when they are sent as arrays.

The Underlying Cause

The main reason for the cascading AuthorizeView failing is the inability of Blazor to correctly interpret claims sent as arrays. For example, if a user has claims like user: ["c", "r", "u", "d"], Blazor struggles to read these properly, consequently leading to incorrect behavior in authorization checks.

Implementing a Solution: Custom ClaimsPrincipalFactory

To resolve this issue, you need to implement a custom ClaimsPrincipalFactory which can handle claims sent as arrays correctly. Here's a step-by-step guide to achieve that:

1. Create the Custom ClaimsPrincipalFactory

First, create a new class named ArrayClaimsPrincipalFactory:

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2. Register the Custom Factory in the Startup File

Next, you need to register the custom claims principal factory in your application's startup. Depending on whether you are using a hosted model or not, you would typically do this in your Program.cs or Startup.cs file:

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Conclusion

By implementing this ArrayClaimsPrincipalFactory, you can ensure that your Blazor application accurately reads and processes claims sent as arrays. After making these changes, your cascading AuthorizeView policies should work as expected, allowing for a more secure user experience and properly protecting your navigation items based on user roles and claims.

Integrating identity management can initially pose some challenges, but with the right tools and understanding, you can enhance your application’s security architecture effectively.

With this solution, you are now equipped to tackle the common issue of cascading authorization in Blazor!