意外的响应代码：与AppFog使用socket.io时出现502错误
错误
当用户打开http://sync.aws.af.cm/时 ，Google Chrome JavaScript控制台会在几秒钟内显示：
Unexpected response code: 502 error 应用程序应该记住文本区域的内容，即使用户刷新页面。 该应用程序在本地工作，但不是当我上传到AppFog，我怀疑问题是502错误。
你知道在这种情况下可能会导致这个错误吗？
我试过了
我尝试将script src=<path_to_socket_io>path在我的客户端从/socket.io/socket.io.js为node_modules/socket.io/node_modules/socket.io-client/dist/socket.io.js ，如此处所述，但没有帮助。
我也尝试在Heroku而不是AppFog上提供应用程序，但是在这种情况下，我仍然遇到了这里描述的问题，即使我指定了socket.io版本0.9.6。
我也看了以下问题，但迄今为止的意见似乎并没有帮助我。
socket.io在连接/ websocket上创build502错误的网关无效
Socket.IO node.js websocket连接无效的端口8081
socket.io与node.js不按预期工作
相关的服务器代码
这里是相关的服务器代码：
var server = http.createServer(function (req, res) { ... }); var io = require('socket.io').listen(server); // Define events that can be triggered by the client io.sockets.on('connection', function (socket) { socket.on('setServerVariable', function (value) { ... }); ... }); server.listen(process.env.VCAPP_APP_PORT || 3000);
相关的客户端代码
<script src="/socket.io/socket.io.js"></script> <script> window.onload = function () { ... var socket = io.connect(window.location.hostname); socket.emit('getServerVariable'); ... }; ...
服务器日志
$ af logs sync ====> /logs/stdout.log <==== info: socket.io started debug: served static content /socket.io.js debug: client authorized info: handshake authorized veNnUVtoDTIz-oudG7Pa debug: setting request GET /socket.io/1/websocket/veNnUVtoDTIz-oudG7Pa debug: set heartbeat interval for client veNnUVtoDTIz-oudG7Pa warn: websocket connection invalid info: transport end (undefined) debug: set close timeout for client veNnUVtoDTIz-oudG7Pa debug: cleared close timeout for client veNnUVtoDTIz-oudG7Pa debug: cleared heartbeat interval for client veNnUVtoDTIz-oudG7Pa debug: served static content /socket.io.js debug: client authorized info: handshake authorized 6AKyhROUNjqujk_uG7Pb debug: setting request GET /socket.io/1/websocket/6AKyhROUNjqujk_uG7Pb debug: set heartbeat interval for client 6AKyhROUNjqujk_uG7Pb warn: websocket connection invalid info: transport end (undefined) debug: set close timeout for client 6AKyhROUNjqujk_uG7Pb debug: cleared close timeout for client 6AKyhROUNjqujk_uG7Pb debug: cleared heartbeat interval for client 6AKyhROUNjqujk_uG7Pb debug: setting request GET /socket.io/1/xhr-polling/6AKyhROUNjqujk_uG7Pb?t=1348504130465 debug: setting poll timeout debug: client authorized for debug: clearing poll timeout debug: xhr-polling writing 1:: debug: set close timeout for client 6AKyhROUNjqujk_uG7Pb debug: setting request GET /socket.io/1/xhr-polling/6AKyhROUNjqujk_uG7Pb?t=1348504130724 debug: setting poll timeout debug: discarding transport debug: cleared close timeout for client 6AKyhROUNjqujk_uG7Pb debug: xhr-polling received data packet 5:::{"name":"getServerVariable"} debug: clearing poll timeout debug: xhr-polling writing 5:::{"name":"printLog"} debug: set close timeout for client 6AKyhROUNjqujk_uG7Pb server.js: getServerVariable: debug: setting request GET /socket.io/1/xhr-polling/6AKyhROUNjqujk_uG7Pb?t=1348504130980 debug: setting poll timeout debug: clearing poll timeout debug: xhr-polling writing 23 5:::{"name":"printLog"} 39 5:::{"name":"setItemValue","args":[""]} 23 5:::{"name":"printLog"} debug: set close timeout for client 6AKyhROUNjqujk_uG7Pb debug: discarding transport debug: cleared close timeout for client 6AKyhROUNjqujk_uG7Pb debug: setting request GET /socket.io/1/xhr-polling/6AKyhROUNjqujk_uG7Pb?t=1348504131261 debug: setting poll timeout debug: discarding transport debug: cleared close timeout for client 6AKyhROUNjqujk_uG7Pb debug: clearing poll timeout debug: xhr-polling writing 8:: debug: set close timeout for client 6AKyhROUNjqujk_uG7Pb debug: xhr-polling closed due to exceeded duration debug: setting request GET /socket.io/1/xhr-polling/6AKyhROUNjqujk_uG7Pb?t=1348504151659 debug: setting poll timeout debug: discarding transport debug: cleared close timeout for client 6AKyhROUNjqujk_uG7Pb
AppFog还不支持websocket。 在他们最近收购了Nodester后，他们宣布将在几个月内推出。
通过添加io.set('transports', ['xhr-polling']); 你只是设置运输到ajax长轮询。 默认情况下，Socket.io根据浏览器function和当前连接来确定最佳传输。 Websockets是理想的，当它是可用的，但如果它不是Socket.io将回落到其他运输xhr轮询。
在使用CloudFlare时，我也收到了同样的502 unexpected response / bad gateway错误，CloudFlare也无法通过其基于nginx的基础结构代理websocket连接（请注意，截至2014年，Cloudflare可以代理websockets，如果您使用的是高级计划）。