在 Node.js 中检测端口 port 是否被占用

[AlexZ33]

    var calledOnce = false

    var timeoutRef = setTimeout(function () {
        calledOnce = true
        callback(false,port)
    }, 2000)

    timeoutRef.unref()

    var connected = false

    server.on('listening', function() {
        clearTimeout(timeoutRef)

        if (server)
            server.close()

        if (!calledOnce) {
            calledOnce = true
            callback(true,port)
        }
    })

    server.on('error', function(err) {
        clearTimeout(timeoutRef)

        var result = true
        if (err.code === 'EADDRINUSE')
            result = false

        if (!calledOnce) {
            calledOnce = true
            callback(result,port)
        }
    })
}

function server(_port){
    var pt = _port || __port;
    probe(pt,function(bl,_pt){
        // 端口被占用 bl 返回false
        // _pt：传入的端口号
        if(bl === true){
            // ssr(_pt)
            server = http.createServer(connListener);
            server = server.listen(parseInt(_pt, 10));
            console.log("\n  Static file server running at" + "\n\n=> http://localhost:" + _pt + '\n');
        }else{
            server(_pt+1)
        }
    })
}