JavaScript构造函数+节点js createServer

Question

Im trying to wrap node js server in JS object, In order to do that, I wrote this constructor:

function staticServerObj (rootFolder) {
    this.rootFolder = rootFolder;
    this.port = null;
    this.isStarted = false;
    this.startedData = null;
    this.numOfCurrentRequests = 0;
    this.numOfAllRequests = 0;
    this.numOfSuccesfulRequest = 0;

    this.serverObj = net.createServer(function (socket) {
        handleNewConnection(this, socket);
    });
};

The problem is, in handleNewConnection function, Im trying to use my staticServerObj vars (like: staticServerObj.port) and it's undefined, Furthermore, when I try to log the server object in that way:

function handleNewConnection(server, socket) {
    console.log(server);
}

Im getting this result:

{ domain: null,
  _events: { connection: [Function] },
  _maxListeners: 10,
  _connections: 1,
  connections: [Getter/Setter],
  _handle: 
   { fd: 12,
     writeQueueSize: 0,
     onconnection: [Function: onconnection],
     owner: [Circular] },
  _usingSlaves: false,
  _slaves: [],
  allowHalfOpen: false,
  _connectionKey: '4:0.0.0.0:1234' }

Any Ideas?

Answer 1

You have a scoping problem. The this inside your createServer() does not point to the server object anymore. To solve this either save a reference to the staticServerObj like this:

function staticServerObj (rootFolder) {
    this.rootFolder = rootFolder;
    this.port = null;
    this.isStarted = false;
    this.startedData = null;
    this.numOfCurrentRequests = 0;
    this.numOfAllRequests = 0;
    this.numOfSuccesfulRequest = 0;

    var that = this;

    this.serverObj = net.createServer(function (socket) {
        handleNewConnection(that, socket);
    });
};

or use bind() and have access to the this reference inside your function:

function staticServerObj (rootFolder) {
    this.rootFolder = rootFolder;
    this.port = null;
    this.isStarted = false;
    this.startedData = null;
    this.numOfCurrentRequests = 0;
    this.numOfAllRequests = 0;
    this.numOfSuccesfulRequest = 0;

    var that = this;

    this.serverObj = net.createServer( handleNewConnection.bind( this ) );
};

function handleNewConnection(socket) {
   // your former server variable can now be accessed using `this`
    console.log( this );
}