socket.io 是否将传输从轮询升级到 websocket？

Question

我正在使用带有 socket.io 的 nodejs 和 express 框架。以下是我运行命令时得到的日志输出

DEBUG=* /bin/www

以下是日志输出。

  engine intercepting request for path "/socket.io/" +2m
  engine handling "GET" http request "/socket.io/?EIO=3&transport=polling&t=1414498393419-0" +0ms
  engine handshaking client "WECN1dP0tobacKc8AAAB" +1ms
  engine:socket sending packet "open" ({"sid":"WECN1dP0tobacKc8AAAB","upgrades":["websocket"],"pingInterval":25000,"pingTimeout":60000}) +0ms
  engine:polling setting request +0ms
  engine:socket flushing buffer to transport +0ms
  engine:polling writing "  �0{"sid":"WECN1dP0tobacKc8AAAB","upgrades":["websocket"],"pingInterval":25000,"pingTimeout":60000}" +1ms
  engine:socket executing batch send callback +1ms
  socket.io:server incoming connection with id WECN1dP0tobacKc8AAAB +2.5m
  socket.io:client connecting to namespace / +1.3m
  socket.io:namespace adding socket to nsp / +2.5m
  socket.io:socket socket connected - writing packet +1.3m
  socket.io:socket joining room WECN1dP0tobacKc8AAAB +0ms
  socket.io:client writing packet {"type":0,"nsp":"/"} +1ms
  socket.io-parser encoding packet {"type":0,"nsp":"/"} +2.5m
  socket.io-parser encoded {"type":0,"nsp":"/"} as 0 +0ms
  engine:socket sending packet "message" (0) +1ms
  socket.io:socket joined room WECN1dP0tobacKc8AAAB +5ms
  engine intercepting request for path "/socket.io/" +140ms
  engine handling "GET" http request "/socket.io/?EIO=3&transport=polling&t=1414498393557-1&sid=WECN1dP0tobacKc8AAAB" +0ms
  engine setting new request for existing client +1ms
  engine:polling setting request +0ms
  engine:socket flushing buffer to transport +0ms
  engine:polling writing "�40" +0ms
  engine:socket executing batch send callback +0ms
  engine upgrading existing transport +39ms
  engine:socket might upgrade socket transport from "polling" to "websocket" +0ms
  engine intercepting request for path "/socket.io/" +16ms
  engine handling "GET" http request "/socket.io/?EIO=3&transport=polling&t=1414498393618-2&sid=WECN1dP0tobacKc8AAAB" +0ms
  engine setting new request for existing client +0ms
  engine:polling setting request +0ms
  engine:ws received "2probe" +2ms
  engine:ws writing "3probe" +0ms
  engine:socket writing a noop packet to polling for fast upgrade +100ms
  engine:polling writing "�6" +0ms
  engine:ws received "5" +4ms
  engine:socket got upgrade packet - upgrading +0ms
  engine:ws received "2" +25s
  engine:socket packet +0ms
  engine:socket got ping +0ms
  engine:socket sending packet "pong" (undefined) +0ms
  engine:socket flushing buffer to transport +0ms
  engine:ws writing "3" +0ms
  engine:ws received "2" +25s
  engine:socket packet +0ms
  engine:socket got ping +0ms
  engine:socket sending packet "pong" (undefined) +0ms
  engine:socket flushing buffer to transport +0ms
  engine:ws writing "3" +0ms
  engine:ws received "2" +25s
  engine:socket packet +0ms
  engine:socket got ping +0ms
  engine:socket sending packet "pong" (undefined) +0ms
  engine:socket flushing buffer to transport +0ms
  engine:ws writing "3" +0ms
  engine:ws received "2" +25s
  engine:socket packet +0ms
  engine:socket got ping +0ms
  engine:socket sending packet "pong" (undefined) +0ms
  engine:socket flushing buffer to transport +0ms
  engine:ws writing "3" +1ms

我没有看到任何确认传输升级的日志消息。乒乓消息也不断发生。

这是否意味着 websocket 传输已建立？

Answer 1

是的，它使用polling first and then upgrades to websocket。我确定如果您使用浏览器连接或使用 wireshark，您会看到来自服务器的“HTTP/1.1 101 Switching Protocols”消息。 您还可以在日志中看到“engine:ws”，这意味着 websocket 正在工作。 如果您仍然不确定，您还可以打印出传输类型（例如断开连接）。这是服务器端代码（socket.io 1.1.0）：

  socket.on('disconnect', function () {
    console.log(socket.id + ' disconnect ('+ socket.client.conn.transport.constructor.name +')';
  });