Socket.io 通过xhr轮询和jsonp轮询超时进行连接

我试着通过websocket和轮询运行我的socket.io程序，它们都能工作。但是，当尝试运行xhr轮询时，它会超时。可能的原因是什么

对于这个程序，我使用socket.io 1.2.1

var options = {"force new connection":true,
               "reconnect":false,
               "connect timeout":10000,
               "flash policy port":843,
               "auto connect":true,
               "path":"/sample/socket.io",
               "transports":["xhr-polling"]}

this.namespace = io.connect( 'http://localhost:8190/', options);

到目前为止，我的研究没有得到任何关于这个问题的信息

编辑：

这是浏览器上的一段日志

socket.io-client:url parse http://localhost:8190/ +0ms
socket.io.js:1284 socket.io-client ignoring socket cache for http://localhost:8190/ +0ms
socket.io.js:1284 socket.io-client:manager readyState closed +0ms
socket.io.js:1284 socket.io-client:manager opening http://localhost:8190/ +0ms
socket.io.js:3524 engine.io-client:socket creating transport "xhr-polling" +0ms
socket.io.js:1284 socket.io-client:manager connect attempt will timeout after 20000 +4ms
socket.io.js:1284 socket.io-client:manager readyState opening +1ms
socket.io.js:1284 socket.io-client:manager connect_error +3ms
socket.io.js:1284 socket.io-client:manager will wait 1000ms before reconnect attempt +2ms
socket.io.js:1284 socket.io-client:manager attempting reconnect +1s
socket.io.js:1284 socket.io-client:manager readyState closed +0ms
socket.io.js:1284 socket.io-client:manager opening http://localhost:8190/ +1ms
socket.io.js:1284 socket.io-client:manager connect attempt will timeout after 20000 +0ms

---

这段日志不断重复，同时不断增加超时时间。

我发现这是因为Socket.IO版本1.0+实际上不允许在[websocket and polling]之外设置传输。将轮询设置为传输默认为轮询xhr，除非在选项中将属性forceJSONP和/或jsonp设置为true

换言之，代码应为：

var options = {"force new connection":true,
               "reconnect":false,
               "connect timeout":10000,
               "flash policy port":843,
               "auto connect":true,
               "path":"/sample/socket.io",
               "transports":["polling"]}

this.namespace = io.connect( 'http://localhost:8190/', options);

还要注意，“自动连接”现在是自动连接，“强制新建连接”现在是强制新建，“连接超时”现在是超时，“重新连接”现在是“重新连接”

var options = {forceNew :true,
               reconnection :false,
               timeout":10000,
               "flash policy port":843,
               autoConnect:true,
               "path":"/sample/socket.io",
               "transports":["polling"]}