Tutorial: a connection through SSH, step by step

The example project apps/hello-ssh reaches a Redis server that only an SSH server (a bastion) can reach: ssh -W host:port, the connection's stream is the stream to Redis. On the computer it is the system's ssh; in the browser, the real OpenSSH client compiled to WebAssembly, linked to your PHP by a pipe.

1. Create the application

bin/jumphp gui:new mon-ssh "Mon SSH" && bin/jumphp install mon-ssh

2. The window

forms/MainForm.form.yaml (copy apps/hello-ssh/forms/MainForm.form.yaml): the SSH server (sshHost, sshPort, sshUser), a « Choose a key file… » button (chooseKey), the key's passphrase (passphrase), the target as seen from the bastion (host, port), a ping button, status, result.

3. The key: the file picker

A browser has no ~/.ssh folder: the file is asked from the person. FilePicker::open() works on the computer AND in the browser (call it from a click); the chosen file arrives at a path that you read and then delete. It is kept in the application's keyring ($this->engine->sshKeyring(): the role of an agent, which the browser does not have).

public function onChooseKey(Button $sender): void
{
    FilePicker::open(['title' => 'SSH private key'])->then(function (?string $file): void {
        if ($file === null) { return; }                                   // annulé
        $text = (string)file_get_contents($file);
        unlink($file);
        $this->engine->sshKeyring()->add(basename($file), $text, $this->passphrase->text);   // nom, clé, phrase secrète
        $this->keyState->text = 'Keys: ' . implode(', ', $this->engine->sshKeyring()->names());
    });
}

The key stays in the application's storage (var/ssh_keyring.json: IndexedDB in the browser, the data folder on the computer) and is never sent to the server: it goes into the SSH client's memory. Each connection offers all the keyring's keys, like an agent.

4. Connect

$options = ['sshHost' => 'bastion.exemple.com', 'sshPort' => 22, 'sshUser' => 'moi', 'sshKeys' => $this->engine->sshKeyring()->all()];
$connection = $this->engine->ssh()->connect('127.0.0.1', 6379, $options);      // 127.0.0.1:6379 vu depuis le bastion
$connection->on('open', fn () => $connection->write("PING\r\n"));
$connection->on('data', fn (string $bytes) => $this->result->text = trim($bytes));
$connection->on('error', fn (string $m) => $this->result->text = $m);          // « Permission denied (publickey) », « Could not resolve hostname »...
$connection->on('knownHosts', fn (string $text) => $this->engine->storage->writeJson('known_hosts.json', ['text' => $text]));   // l'empreinte du serveur, gardée

The same events as with tcp(). For code that takes a Tcp (like the MySQL client of apps/jumphpsql): $this->engine->ssh()->via($options) has the same connect($host, $port, $timeout). The options: docs/ssh-wasm.md.

5. Test

bin/jumphp test mon-ssh      # le trousseau, les champs manquants, un ssh qui n'atteint pas son serveur (le message dit pourquoi)
bin/jumphp shot mon-ssh
bin/jumphp run mon-ssh       # sur l'ordinateur : le ssh du système (votre agent et ~/.ssh marchent aussi)

6. The browser: two rights

bin/jumphp build mon-ssh && bin/jumphp serve mon-ssh

In the browser, two stages go through jumphp.net's TCP bridge, which only accepts approved applications: the SSH client (WebAssembly) connects to the bastion (port 22 or another) → the SSH right is needed. (A SQL client that talks to a database directly needs the TCP right.) Studio → the project → Accès SSH → « Demander l'accès SSH »; the administrator approves it for the published commit.

The SSH right is broader (any port of a public address, never a private address): the administrator only grants it to code they have looked at. Statistics, log, cutting and blocking: Administration → Pont TCP.

7. Check in the browser

Project page on jumphp.net: choose your key (your computer's file picker opens), enter the bastion and the target, click « Send PING through SSH »: The server answered: +PONG. The first seconds show « The SSH session is starting… »: the SSH client starts in a Web Worker (a 3.8 MB file loaded on demand).

How it works (two wasm linked by a pipe), the security and the compilation of OpenSSH: docs/ssh-wasm.md. The first tutorial: docs/tuto-tcp.md.