node.js - socket.io 客户端持续重试无法访问的主机

Question

我正在尝试从我的 socket.io-client(在 Node.js 上运行)到远程 Websocket 建立持久连接。我无法控制远程套接字，有时它可能会完全崩溃。每当发生错误或断开连接时，我想尝试重新连接()。在下面的示例中，我尝试测试远程主机拒绝连接的情况。在这种情况下，我想在 1 秒后尝试重新连接。它第二次调用，然后退出。

代码如下:

var events = require('events'),
    util = require('util'),
    io = require('socket.io-client'),
    url = "ws://localhost:12345", // intentionally an unreachable URL
    socketOptions = {
        "transports" : [ "websocket" ],
        "try multiple transports" : false,
        "reconnect" : false,
        "connect timeout" : 5000
    };


// The goal is to have this socket attempt to connect forever
// I would like to do it without the built in reconnects, as these
// are somewhat unreliable (reconnect* events not always firing)

function Test(){
    var self = this;
    events.EventEmitter.call(self);

    var socket;

    function reconnect(){
        setTimeout(go, 1000);
    }

    function go(){

        console.log("connecting to", url, socketOptions);

        socket = io.connect(url, socketOptions);

        socket.on('connect', function(){
            console.log("connected! wat.");
        });

        socket.on('error', function(err){
            console.log("socket.io-client 'error'", err);
            reconnect();
        });

        socket.on('connect_failed', function(){
            console.log("socket.io-client 'connect_failed'");
            reconnect();
        });

        socket.on('disconnect', function(){
            console.log("socket.io-client 'disconnect'");
            reconnect();
        });
    }

    go();
}

util.inherits(Test, events.EventEmitter);


var test = new Test();


process.on('exit', function(){
    console.log("this should never end");
});

在 Node 0.11.0 下运行它时，我得到以下信息:

$ node socketio_websocket.js 
connecting to ws://localhost:12345 { transports: [ 'websocket' ],
  'try multiple transports': false,
  reconnect: false,
  'connect timeout': 5000 }
socket.io-client 'error' Error: connect ECONNREFUSED
    at errnoException (net.js:878:11)
    at Object.afterConnect [as oncomplete] (net.js:869:19)
connecting to ws://localhost:12345 { transports: [ 'websocket' ],
  'try multiple transports': false,
  reconnect: false,
  'connect timeout': 5000 }
this should never end

Answer 1

ECONNREFUSED 是您无法管理的异常。试试这个:

process.on('uncaughtException', function(err) {
    if(err.code == 'ECONNREFUSED'){
        reconnect();
    }
}

编辑

修改选项如下:

socketOptions = {
    "transports" : [ "websocket" ],
    "try multiple transports" : false,
    "reconnect" : false,
    'force new connection': true, // <-- Add this!
    "connect timeout" : 5000
};

以及重新连接功能(请查看注释中的说明)

function reconnect(){
    socket.removeAllListeners();
    setTimeout(go, 1000);
}

socket.io 可能会重用相同的连接而不创建新的连接，从而强制应用程序正常工作