index.js

var spawn = require("child_process").spawn;
var Url = require("url");
var shell = require("minish");
var SFTP = require("sftp-ws");

var StreamChannel = SFTP.Internals.StreamChannel;
var WebSocketChannelFactory = SFTP.Internals.WebSocketChannelFactory;

// parse arguments with minimist
var args = shell.parse(process.argv);
var url = args._[2];
var mountpoint = args._[3];
var path = "" + args.path;

// handle arguments
if (args.h) {
    console.log("usage: vfs url mountpoint [options]");
    process.exit(1);
} else if (!url) {
    console.log("missing url");

    if (!mountpoint) {
        console.log("see `vfs -h` for usage");
    }

    process.exit(1);
} else if (!mountpoint) {
    console.log("missing mountpoint");
    process.exit(1);
}

// connect and authenticate
url = Url.parse(url);
var factory = new WebSocketChannelFactory();
var options = { authenticate: authenticate, protocol: "sftp" };
console.log("connecting to %s", url.host);
factory.connect(Url.format(url), options, function (err, remote) {
    if (err) return error(err);

    console.log("connected");

    // spawn `sshfs` in slave mode
    var child;
    try {
	    child = spawn("sshfs", [url.hostname + ":" + path, mountpoint, "-o", "slave"], { stdio: ["pipe", "pipe", process.stderr] });
    } catch (err) {
	    return error(err);
    }

    var local = new StreamChannel(child.stdout);

    var state = 0;

    local.on("message", function (packet) {
    	//console.log("->", packet);
	    remote.send(packet);
    });

    local.on("close", function () {
	    remote.close();
    });

    remote.on("message", function (packet) {
	    //console.log("<-", packet);
	    child.stdin.write(packet);
    });

    remote.on("close", function () {
	    local.close();
    });

    child.on("exit", function (code, signal) {
        //console.log("exit");
	    process.exit(code);
    });

    console.log("press Ctrl+C to exit");
});

function error(err) {
    console.log(err);
    process.exit(255);
}

// authenticate the client
function authenticate(instructions, queries, callback) {
    if (instructions) shell.write(instructions);
    
    var credentials = {};
    next();
    
    function next() {
        var query = queries.shift();
        
        // no more queries -> pass the credentials to the callback
        if (!query) return callback(credentials);
        
        // query the user for credentials
        if (query.secret) {
            shell.password(query.prompt, reply);
        } else {
            shell.question(query.prompt, reply);
        }
        
        function reply(value) {
            credentials[query.name] = value;
            next();
        }
    }
}