使用Nodejs + SocketIO时丢弃传输错误

Question

I am building an android chat application. I am using nodejs at server end and trying to implement android client for socketIO using this . First the client echoes "hello" to the server and the server echoes it back to the client. This works fine. Now there is a Button , which when pressed echoes the text in the EditText to the server. Server is supposed to echo the text back to the client. However, as soon as text is echoed to the server, I get Discarding transport error at server end and nothing is echoed back. Client is unable to echo anything further. What is wrong with the codes ?

Server

var http = require('http'),fs = require('fs');

var app = http.createServer(function (req, res) {

res.end();
                                                      }).listen(8000, '127.0.0.1');

var io = require('socket.io').listen(app);

io.sockets.on('connection', function(socket) {
socket.on('echo', function(data) {
socket.emit('echoback', data);
});
});

Client

 package com.jack.pri;
 import java.net.MalformedURLException;
 import org.json.JSONException;
 import org.json.JSONObject;
 import android.os.Bundle;
 import android.app.Activity;
 import android.util.Log;
 import android.view.KeyEvent;
 import android.view.Menu;
 import android.view.View;
 import android.view.View.OnClickListener;
 import android.view.View.OnKeyListener;
 import android.widget.Button;
 import android.widget.EditText;
 import android.widget.TextView;
 import io.socket.*;

    public class MainActivity extends Activity {
private SocketIO socket;
private TextView tview;
private Button btn;
private EditText tt;
private String k;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    tview=(TextView) findViewById(R.id.tv);

     tt = (EditText) findViewById(R.id.et);
          btn = (Button) findViewById(R.id.button1);


    //socket = null;
    try {
        socket = new SocketIO("http://10.0.2.2:8000");
    } catch (MalformedURLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    socket.connect(new IOCallback() {
        @Override
        public void on(String event, IOAcknowledge ack, Object... args) {
            if ("echoback".equals(event) && args.length > 0) {
               tview.setText(""+args[0]);
               Log.e("received",""+args[0]);
            }
        }

        @Override
        public void onMessage(JSONObject json, IOAcknowledge ack) {}
        @Override
        public void onMessage(String data, IOAcknowledge ack) {}
        @Override
        public void onError(SocketIOException socketIOException) { socketIOException.printStackTrace();}
        @Override
        public void onDisconnect() {}
        @Override
        public void onConnect() {}
    });

    ///
    socket.emit("echo", "hello");

    btn.setOnClickListener(new OnClickListener() {

        public void onClick(View arg0) {

   k=tt.getText().toString();
   socket.emit("echo", k);          

        }

    });

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.activity_main, menu);
    return true;
}

}

Errorlog at server end

debug - client authorized
info  - handshake authorized kaHbMG-lFmuFtvkFGY2W
debug - setting request GET /socket.io/1/websocket/kaHbMG-lFmuFtvkFGY2W
debug - set heartbeat interval for client kaHbMG-lFmuFtvkFGY2W
debug - client authorized for 
debug - websocket writing 1::
debug - websocket writing 5:::{"name":"echoback","args":["hello"]}
debug - emitting heartbeat for client kaHbMG-lFmuFtvkFGY2W
debug - websocket writing 2::
debug - set heartbeat timeout for client kaHbMG-lFmuFtvkFGY2W
debug - got heartbeat packet
debug - cleared heartbeat timeout for client kaHbMG-lFmuFtvkFGY2W
debug - set heartbeat interval for client kaHbMG-lFmuFtvkFGY2W
debug - websocket writing 5:::{"name":"echoback","args":["this is textbox input text"]}
info  - transport end (undefined)
debug - set close timeout for client kaHbMG-lFmuFtvkFGY2W
debug - cleared close timeout for client kaHbMG-lFmuFtvkFGY2W
debug - cleared heartbeat interval for client kaHbMG-lFmuFtvkFGY2W
debug - discarding transport

Answer 1

I think you need to explicitly configure the socket - this code from the github documentation [https://github.com/LearnBoost/Socket.IO/wiki/Configuring-Socket.IO] - one of the polling options would make the problem go away.

var io = require('socket.io').listen(80);

io.configure('production', function(){
  io.enable('browser client etag');
  io.set('log level', 1);

  io.set('transports', [
    'websocket'
  , 'flashsocket'
  , 'htmlfile'
  , 'xhr-polling'
  , 'jsonp-polling'
  ]);
});

io.configure('development', function(){
  io.set('transports', ['websocket']);
});