NodeJS中远程主机上的Spawn进程

Question

I have a simple Node server that serves a page with a button. On click that button needs to execute a command on a remote host. When the command finishes, the output should then be given to the response of the function and shown in the html.

Currently this is the server code:

app.use(logger("combined"));
app.use(bodyParser.urlencoded({ extended: true }));
app.use(bodyParser.json());

app.get('/index.html', function (req, res) {
    res.sendFile( __dirname + "/" + "index.html" );
})

app.post('/connect', function (req, res) {
    var spawn = require('cross-spawn-async');
    var mpiProc = spawn('ssh','pi@raspi2','"ls"', { stdio: ['pipe','pipe',2,'pipe'] });

    var grid = "...8.1..........435............7.8........1...2..3....6......75..34........2..6..";
    str = "";
    mpiProc.stdout.on('data', function(data) {
        console.log(data);
        str = data.toString();
        res.write('data: ' + JSON.stringify({ msg : str }) + '\n\n');
        // Output       
    });

    mpiProc.on('close', function(code) {
        res.end(str);
        // Script exit code
    });

    mpiProc.on('error', function(code) {
        res.end('stderr: ' + code);
        // Script exit code
    });
}) 
    require('http').createServer(app).listen(3000, function(){
    console.log('Listening on 3000');
});

As you can see the following call tries to execute the 'ls' command on a remote host:

var mpiProc = spawn('ssh','pi@raspi2','"ls"', { stdio: ['pipe','pipe',2,'pipe'] });

But this doesn't return anything, while executed from the server directly from terminal, it returns the list of directory content. To test if the command works this way with a spawn I tried doing this:

var mpiProc = spawn('ls', { stdio: ['pipe','pipe',2,'pipe'] });

Which returns what I expected, the list of directory content on the server. So how can I create a pipe to a remote host to execute a command and then store the result of the command on the server?

Answer 1

The second argument passed to spawn() is an array of arguments. Also, you don't need to manually quote your arguments. This should work:

spawn('ssh', ['pi@raspi2', 'ls'], { stdio: ['pipe', 'pipe', 2, 'pipe'] });

Lastly, if you want more programmatic (and lightweight) control over the ssh connection, there is the ssh2 module (or any of the modules that build on top of it), which does not use child processes.