Snippet

Refining API Error Responses with AuthenticationEntryPoint

AuthenticationEntryPoint is triggered when an unauthenticated user attempts to access a protected resource. Implementing this allows for returning structured JSON errors instead of default HTML redirect pages in REST APIs.

snippet.java

java

@Component
public class ApiAuthEntryPoint implements AuthenticationEntryPoint {
    @Override
    public void commence(HttpServletRequest request, HttpServletResponse response, 
                         AuthenticationException authException) throws IOException {
        response.setStatus(HttpServletResponse.SC_UNAUTHORIZED);
        response.setContentType("application/json");
        response.getWriter().write("{\"error\": \"Invalid credentials\", \"timestamp\": \"" + Instant.now() + "\"}");
    }
}

spring

Breakdown

commence(...)

Method executed when authentication fails, providing access to the response stream.

SC_UNAUTHORIZED

Standard HTTP 401 status code indicating that authentication is required.

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Refining API Error Responses with AuthenticationEntryPoint

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