When you raise an exception, as would happen with normal Python, the rest of the execution is aborted. This way you can raise these exceptions from anywhere in the code to abort a request and show the error to the client.

You can use:

* `HTTPException`
* `WebSocketException`

These exceptions can be imported directly from `fastapi`:

```python

## Example Lambda handler

Install the necessary dependencies.
```sh
pip install flask requests
```

Following is an example lambda handler.
```py
from flask import Flask, request, abort, make_response
import requests

app = Flask(__name__)
@app.route('/', methods=['POST'])
def get_webhook():
	if request.method == 'POST':
		# obtain the request event from the 'POST' call
		event = request.json

          try {
            bytesRead = source.read(sink, byteCount)
          } catch (e: IOException) {
            if (!cacheRequestClosed) {
              cacheRequestClosed = true
              cacheRequest.abort() // Failed to write a complete cache response.
            }
            throw e
          }

          if (bytesRead == -1L) {
            if (!cacheRequestClosed) {
              cacheRequestClosed = true

import jcifs.internal.smb1.ServerMessageBlock;

/**
 * SMB1 NT Cancel command implementation.
 * Provides functionality to cancel previously issued SMB1 NT transaction commands
 * that are in progress, allowing clients to abort long-running operations.
 *
 * @author mbechler
 */
public class SmbComNtCancel extends ServerMessageBlock {

    /**
     * Constructs an NT cancel command.
     *
     * @param config the configuration

	minisign -qQSm ./minio-${arch}.${release} -s "$CRED_DIR/minisign.key" <"$CRED_DIR/minisign-passphrase"

	sha256sum_str=$(sha256sum <./minio-${arch}.${release})
	rc=$?
	if [ "$rc" -ne 0 ]; then
		abort "unable to generate sha256sum for ${1}"
	fi
	echo "${sha256sum_str// -/minio.${release}}" >./minio-${arch}.${release}.sha256sum
}

function main() {
	echo "Testing builds for OS/Arch: ${SUPPORTED_OSARCH}"

    if (success && !entry.readable) {
      for (i in 0 until valueCount) {
        if (!editor.written!![i]) {
          editor.abort()
          throw IllegalStateException("Newly created entry didn't create value for index $i")
        }
        if (!fileSystem.exists(entry.dirtyFiles[i])) {
          editor.abort()
          return
        }
      }
    }

    for (i in 0 until valueCount) {

                        }
                    }
                }
            }
        } catch (final CrawlerSystemException e) {
            httpGet.abort();
            throw e;
        } catch (final Exception e) {
            httpGet.abort();
            throw new CrawlingAccessException("Could not process " + robotTxtUrl + ". ", e);
        } finally {
            EntityUtils.consumeQuietly(httpEntity);

            super.close()
            editor.commit()
          }
        }
    }

    override fun abort() {
      synchronized(this@Cache) {
        if (done) return
        done = true
        writeAbortCount++
      }
      cacheOut.closeQuietly()
      try {
        editor.abort()
      } catch (_: IOException) {
      }
    }

    override fun body(): Sink = body
  }

# specifically. Use your best judgment to keep the scripts in this directory
# lean and easy to follow. When in doubt, remember that for CI scripts, "keep it
# simple" is MUCH more important than "don't repeat yourself."

# -e: abort script if one command fails
# -u: error if undefined variable used
# -x: log all commands
# -o pipefail: entire command fails if pipe fails. watch out for yes | ...
# -o history: record shell history

fs.s3a.secret.key=minio123
fs.s3a.path.style.access=true
fs.s3a.block.size=512M
fs.s3a.buffer.dir=${hadoop.tmp.dir}/s3a
fs.s3a.committer.magic.enabled=false
fs.s3a.committer.name=directory
fs.s3a.committer.staging.abort.pending.uploads=true
fs.s3a.committer.staging.conflict-mode=append
fs.s3a.committer.staging.tmp.path=/tmp/staging
fs.s3a.committer.staging.unique-filenames=true
fs.s3a.connection.establish.timeout=5000