Solving the Empty Error Message with Custom AuthenticationEntryPoint in Spring Boot

Описание: Discover how to configure Spring Boot and Spring Security to return custom error messages from your `AuthenticationEntryPoint`, ensuring a seamless API authentication experience.
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This video is based on the question https://stackoverflow.com/q/63730436/ asked by the user 'Miller Dong' ( https://stackoverflow.com/u/10443611/ ) and on the answer https://stackoverflow.com/a/63732087/ provided by the user 'Nemanja' ( https://stackoverflow.com/u/5859654/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Understanding the Issue: Empty Error Messages in Spring Boot Authentication

When developing a RESTful API using Spring Boot, handling authentication properly is critical for user security and experience. One common issue developers encounter is that when there is an authentication failure (for instance, when a user logs in with incorrect credentials), the error message returned in the response can often be empty. This can lead to confusion, both for the API consumers who receive a generic error and for the developers who are trying to troubleshoot issues.

A user recently faced this scenario while implementing a custom AuthenticationEntryPoint. They correctly logged the error messages but found that the API's response contained no error message, leading them to question what might have gone wrong. Let’s explore how to solve this problem effectively.

The Custom AuthenticationEntryPoint Code

Here's the relevant code snippet the user provided for their custom AuthenticationEntryPoint implementation:

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

In this code, the logger captures the error message correctly, but the HTTP response returns an empty message. Also, the SecurityConfig configuration ensures that the custom entry point is used effectively. The underlying question is: why does the response not include the error message?

Solution: Configuring server.error.include-message

The root cause of the problem lies in the default configuration of error messages in Spring Boot. By default, the property server.error.include-message is set to never, which means that error messages are not included in the responses sent to clients.

Steps to Fix the Issue

To resolve this problem, you need to adjust your application.yaml or application.properties configuration file to ensure that error messages are included in the API responses. Here’s how to do that:

Open your application configuration file (application.yaml or application.properties).

Add the following configuration:

If you are using application.yaml:

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

If you are using application.properties:

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

Explanation of Configuration

include-message: Setting this to always ensures that detailed error messages are included in the response when an error occurs.

include-binding-errors: This property allows you to include validation binding errors, which can also be vital when working with user input.

Final Notes

With these configuration changes in place, your API will now include meaningful error messages in the response for unauthorized errors. This not only improves the user experience but also assists developers in diagnosing issues more efficiently.

By properly configuring your Spring Boot application, you ensure that your users receive the information they need while debugging potential problems with login credentials. Enjoy building secure and user-friendly applications!