This can make it a lot easier for your users to **implement their APIs** to receive your **webhook** requests, they might even be able to autogenerate some of their own API code.

/// info

Webhooks are available in OpenAPI 3.1.0 and above, supported by FastAPI `0.99.0` and above.

///

## An app with webhooks { #an-app-with-webhooks }

proprietary headers can be added <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers" class="external-link" target="_blank">using the 'X-' prefix</a>.

But if you have custom headers that you want a client in a browser to be able to see, you need to add them to your CORS configurations (read more in [CORS (Cross-Origin Resource Sharing)](../tutorial/cors.md){.internal-link target=_blank}), using the parameter `expose_headers` documented in <a href="https://www.starlette.io...

</div>

/// info

Have in mind that, as **browsers handle cookies** in special ways and behind the scenes, they **don't** easily allow **JavaScript** to touch them.

If you go to the **API docs UI** at `/docs` you will be able to see the **documentation** for cookies for your *path operations*.

        more appropriate.


        It's okay if you can't provide complete context on a use case. We understand if you are not
        able to discuss the full details of what you're working on.


        But Guava aims to provide functionality that is useful across boundaries of projects,

The main limitation is that to update or delete content of a file inside a ZIP file the entire ZIP file must be replaced.

## How to enable S3 ZIP behavior ?

        // Success should reset counter
        assertTrue(rateLimiter.checkAttempt(username, ip));
        rateLimiter.recordSuccess(username, ip);

        // Should be able to fail 3 more times before lockout
        for (int i = 0; i < 3; i++) {
            assertTrue(rateLimiter.checkAttempt(username, ip));
            rateLimiter.recordFailure(username, ip);
        }

Also, before that, in previous versions, the `request` object was passed as part of the key-value pairs in the context for Jinja2.

///

/// tip

By declaring `response_class=HTMLResponse` the docs UI will be able to know that the response will be HTML.

///

/// note | Technical Details

You could also use `from starlette.templating import Jinja2Templates`.

 */
abstract class EventListener {
  /**
   * Invoked as soon as a call is enqueued or executed by a client. In case of thread or stream
   * limits, this call may be executed well before processing the request is able to begin.
   *
   * This will be invoked only once for a single [Call]. Retries of different routes or redirects
   * will be handled within the boundaries of a single [callStart] and [callEnd]/[callFailed] pair.
   */

      } finally {
        monitor.leave();
      }
    } else {
      // It is possible due to races that we are currently in the expected state even though we
      // timed out. e.g. if we weren't event able to grab the lock within the timeout we would never
      // even check the guard. I don't think we care too much about this use case but it could lead
      // to a confusing error message.

            <type>pom</type>
            <scope>compile</scope>
        </dependency>

        <!-- For tests only. Must be in compile scope such that the Teamcity generate goal is able to compile the tests -->
        <dependency>
            <groupId>io.mockk</groupId>
            <artifactId>mockk-jvm</artifactId>
            <version>${mockk.version}</version>
        </dependency>