Wir können denselben Ansatz auch verwenden, um in einem Exceptionhandler auf den Requestbody zuzugreifen.

Alles, was wir tun müssen, ist, den Request innerhalb eines `try`/`except`-Blocks zu handhaben:

```Python hl_lines="13  15"
{!../../../docs_src/custom_request_and_route/tutorial002.py!}
```

     * uses 10 MiB).
     */
    const val DEFAULT_INITIAL_WINDOW_SIZE = 65535

    /** HTTP/2: Size in bytes of the table used to decode the sender's header blocks. */
    const val HEADER_TABLE_SIZE = 1

    /** HTTP/2: The peer must not send a PUSH_PROMISE frame when this is 0. */
    const val ENABLE_PUSH = 2

    /** Sender's maximum number of concurrent streams. */

fs.s3a.impl=org.apache.hadoop.fs.s3a.S3AFileSystem

fs.s3a.committer.threads=2048 # Number of threads writing to MinIO
fs.s3a.connection.maximum=8192 # Maximum number of concurrent conns
fs.s3a.fast.upload.active.blocks=2048 # Number of parallel uploads
fs.s3a.fast.upload.buffer=disk # Use disk as the buffer for uploads
fs.s3a.fast.upload=true # Turn on fast upload mode
fs.s3a.max.total.tasks=2048 # Maximum number of parallel tasks

 * Fix: Eliminate rare race condition in SPDY streams that would prevent connection reuse.
 * Fix: Change HTTP date formats to UTC to conform to RFC2616 section 3.3.
 * Fix: Support SPDY header blocks with trailing bytes.
 * Fix: Allow `;` as separator for `Cache-Control` header.
 * Fix: Correct bug where HTTPS POST requests were always automatically buffered.
 * Fix: Honor read timeout when parsing SPDY headers.

                return false
            }

            return true
        }

        private inline fun withElement(element: FirElement, block: () -> Unit) {
            stack.addLast(element)
            try {
                block()
            } finally {
                stack.removeLast()
            }
        }
    }

{!../../../docs_src/custom_response/tutorial008.py!}
```

1. Das ist die Generatorfunktion. Es handelt sich um eine „Generatorfunktion“, da sie `yield`-Anweisungen enthält.
2. Durch die Verwendung eines `with`-Blocks stellen wir sicher, dass das dateiähnliche Objekt geschlossen wird, nachdem die Generatorfunktion fertig ist. Also, nachdem sie mit dem Senden der Response fertig ist.

It is also built to work as a future reference.

So you can come back and see exactly what you need.

## Run the code

All the code blocks can be copied and used directly (they are actually tested Python files).

To run any of the examples, copy the code to a file `main.py`, and start `fastapi dev` with:

<div class="termy">

```console

    assertThat(first.requestLine).isEqualTo("GET / HTTP/1.1")
    val redirect = server.takeRequest()
    assertThat(redirect.requestLine).isEqualTo("GET /new-path HTTP/1.1")
  }

  /**
   * Test that MockWebServer blocks for a call to enqueue() if a request is made before a mock
   * response is ready.
   */
  @Test
  fun dispatchBlocksWaitingForEnqueue() {
    Thread {
      try {
        Thread.sleep(1000)

     * -----END PRIVATE KEY-----
     * ```
     *
     * The string should contain exactly one certificate and one private key in [PKCS #8][rfc_5208]
     * format. It should not contain any other PEM-encoded blocks, but it may contain other text
     * which will be ignored.
     *
     * Encode a held certificate into this format by concatenating the results of

    **FastAPI** uses them internally to achieve this.

## Dependencies with `yield` and `HTTPException`

You saw that you can use dependencies with `yield` and have `try` blocks that catch exceptions.

The same way, you could raise an `HTTPException` or similar in the exit code, after the `yield`.

!!! tip