# Authentication Events

For each authentication that succeeds or fails, a `AuthenticationSuccessEvent` or `AbstractAuthenticationFailureEvent` is fired, respectively.

To listen for these events, you must first publish an `AuthenticationEventPublisher`.
Spring Security’s `DefaultAuthenticationEventPublisher` will probably do fine:

Java

```
@Bean
public AuthenticationEventPublisher authenticationEventPublisher
        (ApplicationEventPublisher applicationEventPublisher) {
    return new DefaultAuthenticationEventPublisher(applicationEventPublisher);
}
```

Kotlin

```
@Bean
fun authenticationEventPublisher
        (applicationEventPublisher: ApplicationEventPublisher?): AuthenticationEventPublisher {
    return DefaultAuthenticationEventPublisher(applicationEventPublisher)
}
```

Then, you can use Spring’s `@EventListener` support:

Java

```
@Component
public class AuthenticationEvents {
	@EventListener
    public void onSuccess(AuthenticationSuccessEvent success) {
		// ...
    }

    @EventListener
    public void onFailure(AbstractAuthenticationFailureEvent failures) {
		// ...
    }
}
```

Kotlin

```
@Component
class AuthenticationEvents {
    @EventListener
    fun onSuccess(success: AuthenticationSuccessEvent?) {
        // ...
    }

    @EventListener
    fun onFailure(failures: AbstractAuthenticationFailureEvent?) {
        // ...
    }
}
```

While similar to `AuthenticationSuccessHandler` and `AuthenticationFailureHandler`, these are nice in that they can be used independently from the servlet API.

## Adding Exception Mappings

`DefaultAuthenticationEventPublisher` by default will publish an `AbstractAuthenticationFailureEvent` for the following events:

|           Exception            |                    Event                     |
|--------------------------------|----------------------------------------------|
|   `BadCredentialsException`    |  `AuthenticationFailureBadCredentialsEvent`  |
|  `UsernameNotFoundException`   |  `AuthenticationFailureBadCredentialsEvent`  |
|   `AccountExpiredException`    |     `AuthenticationFailureExpiredEvent`      |
|  `ProviderNotFoundException`   | `AuthenticationFailureProviderNotFoundEvent` |
|      `DisabledException`       |     `AuthenticationFailureDisabledEvent`     |
|       `LockedException`        |      `AuthenticationFailureLockedEvent`      |
|`AuthenticationServiceException`| `AuthenticationFailureServiceExceptionEvent` |
| `CredentialsExpiredException`  |`AuthenticationFailureCredentialsExpiredEvent`|
| `InvalidBearerTokenException`  |  `AuthenticationFailureBadCredentialsEvent`  |

The publisher does an exact `Exception` match, which means that sub-classes of these exceptions won’t also produce events.

To that end, you may want to supply additional mappings to the publisher via the `setAdditionalExceptionMappings` method:

Java

```
@Bean
public AuthenticationEventPublisher authenticationEventPublisher
        (ApplicationEventPublisher applicationEventPublisher) {
    Map<Class<? extends AuthenticationException>,
        Class<? extends AbstractAuthenticationFailureEvent>> mapping =
            Collections.singletonMap(FooException.class, FooEvent.class);
    AuthenticationEventPublisher authenticationEventPublisher =
        new DefaultAuthenticationEventPublisher(applicationEventPublisher);
    authenticationEventPublisher.setAdditionalExceptionMappings(mapping);
    return authenticationEventPublisher;
}
```

Kotlin

```
@Bean
fun authenticationEventPublisher
        (applicationEventPublisher: ApplicationEventPublisher?): AuthenticationEventPublisher {
    val mapping: Map<Class<out AuthenticationException>, Class<out AbstractAuthenticationFailureEvent>> =
            mapOf(Pair(FooException::class.java, FooEvent::class.java))
    val authenticationEventPublisher = DefaultAuthenticationEventPublisher(applicationEventPublisher)
    authenticationEventPublisher.setAdditionalExceptionMappings(mapping)
    return authenticationEventPublisher
}
```

## Default Event

And, you can supply a catch-all event to fire in the case of any `AuthenticationException`:

Java

```
@Bean
public AuthenticationEventPublisher authenticationEventPublisher
        (ApplicationEventPublisher applicationEventPublisher) {
    AuthenticationEventPublisher authenticationEventPublisher =
        new DefaultAuthenticationEventPublisher(applicationEventPublisher);
    authenticationEventPublisher.setDefaultAuthenticationFailureEvent
        (GenericAuthenticationFailureEvent.class);
    return authenticationEventPublisher;
}
```

Kotlin

```
@Bean
fun authenticationEventPublisher
        (applicationEventPublisher: ApplicationEventPublisher?): AuthenticationEventPublisher {
    val authenticationEventPublisher = DefaultAuthenticationEventPublisher(applicationEventPublisher)
    authenticationEventPublisher.setDefaultAuthenticationFailureEvent(GenericAuthenticationFailureEvent::class.java)
    return authenticationEventPublisher
}
```

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