}

		if tlsPrivateKey != "" && tlsPublicCert == "" {
			logger.Fatal(fmt.Errorf("invalid TLS arguments provided missing public cert --ftp=\"tls-public-cert=path/to/public.crt\""), "unable to start FTP server")
		}
		if port == 0 {
			port = 8021 // Default FTP port, since no port was given.
		}
	}

	//  certs/
	//   │
	//   ├─ public.crt
	//   ├─ private.key
	//   │
	//   ├─ example.com/
	//   │   │
	//   │   ├─ public.crt
	//   │   └─ private.key
	//   └─ foobar.org/
	//      │
	//      ├─ public.crt
	//      └─ private.key
	//   ...
	//
	// Therefore, we read all filenames in the cert directory and check

If you can help me with that, **you are helping me maintain FastAPI** and making sure it keeps **advancing faster and better**. 🚀

## Join the chat { #join-the-chat }

Join the 👥 <a href="https://discord.gg/VQjSZaeJmf" class="external-link" target="_blank">Discord chat server</a> 👥 and hang out with others in the FastAPI community.

/// tip

Use o chat apenas para outro tipo de assunto.

///

### Não faça perguntas no chat

Nutzen Sie den Chat nur für andere allgemeine Gespräche.

///

### Den Chat nicht für Fragen verwenden

Si puedes ayudarme con eso, **me estás ayudando a mantener FastAPI** y asegurando que siga **avanzando más rápido y mejor**. 🚀

## Únete al chat

Únete al servidor de chat 👥 <a href="https://discord.gg/VQjSZaeJmf" class="external-link" target="_blank">Discord</a> 👥 y charla con otros en la comunidad de FastAPI.

/// tip | Consejo

  stars: 5978
  owner_login: hatchet-dev
  owner_html_url: https://github.com/hatchet-dev
- name: serge
  html_url: https://github.com/serge-chat/serge
  stars: 5751
  owner_login: serge-chat
  owner_html_url: https://github.com/serge-chat
- name: fastapi-users
  html_url: https://github.com/fastapi-users/fastapi-users
  stars: 5517
  owner_login: fastapi-users

	const MaxIntermediateCAs = 10
	var (
		peerCertificates = make([]*x509.Certificate, 0, len(r.TLS.PeerCertificates))
		intermediates    *x509.CertPool
		numIntermediates int
	)
	for _, cert := range r.TLS.PeerCertificates {
		if cert.IsCA {
			numIntermediates++
			if numIntermediates > MaxIntermediateCAs {

		return errors.New("public key authority validation requested but no ca public key specified.")
	}

	cert, ok := clientKey.(*ssh.Certificate)
	if !ok {
		return errSftpPublicKeyWithoutCert
	}

	// ssh.CheckCert called by ssh.Authenticate accepts certificates
	// with empty principles list so we block those in here.
	if len(cert.ValidPrincipals) == 0 {
		return errSftpCertWithoutPrincipals
	}

* Write messages from them.
* Then close one of the tabs.

That will raise the `WebSocketDisconnect` exception, and all the other clients will receive a message like:

```
Client #1596980209979 left the chat
```

/// tip

The app above is a minimal and simple example to demonstrate how to handle and broadcast messages to several WebSocket connections.