英文:
How to store websocket connection in GO
问题
我想将客户端的 WebSocket 连接存储到 wsList 中，并统一发送响应。但是它会返回 "use of closed network connection"。如何修复这个问题？
import (
"code.google.com/p/go.net/websocket"
...
)
var wsList []*websocket.Conn
func WShandler(ws *websocket.Conn) {
wsList = append(wsList, ws)
go sendmsg()
}
func sendmsg() {
for _, conn := range wsList {
if err := websocket.JSON.Send(conn, outmsg); err != nil {
fmt.Printf("%s", err) // "use of closed network connection"
}
}
}
你可以在 sendmsg 函数中添加错误处理，检查连接是否已关闭。可以使用 websocket.JSON.Send 方法的返回值来判断连接是否关闭，如果连接已关闭，则不再发送消息。例如：
func sendmsg() {
for _, conn := range wsList {
if websocket.JSON.Send(conn, outmsg) != nil {
if websocket.IsCloseError(err, websocket.CloseNormalClosure) {
// 连接已关闭，不再发送消息
continue
}
fmt.Printf("%s", err)
}
}
}
这样，当连接已关闭时，就不会再尝试发送消息，避免了 "use of closed network connection" 的错误。
英文:
I want to store client websocket connection into wsList, and send response in uniform. but it will return "use of closed network connection". How to fix it?
import {
"code.google.com/p/go.net/websocket"
...
}
var wsList []*websocket.Conn
func WShandler(ws *websocket.Conn) {
wsList = append(wsList, ws)
go sendmsg()
}
func sendmsg() {
for _, conn := range wsList {
if err := websocket.JSON.Send(conn, outmsg); err != nil {
fmt.Printf("%s", err) //"use of closed network connection"
}
}
}
答案1
得分: 3
连接ws在WsHandler返回时关闭。为了解决这个问题，可以通过在循环中读取消息直到检测到错误来防止WsHandler返回：
func WShandler(ws *websocket.Conn) {
wsList = append(wsList, ws)
go sendmsg()
for {
var s string
if err := websocket.Message.Receive(ws, &s); err != nil {
break
}
}
// 在这里从wsList中移除ws
}
wsList存在竞态条件。可以使用互斥锁来保护它。
英文:
The connection ws is closed when WsHandler returns. To fix the problem, prevent WsHandlerfrom returning by reading messages in a loop until an error is detected:
func WShandler(ws *websocket.Conn) {
wsList = append(wsList, ws)
go sendmsg()
for {
var s string
if err := websocket.Message.Receive(ws, &s); err != nil {
break
}
}
// remove ws from wsList here
}
There's a race on wsList. Protect it with a mutex.
答案2
得分: 2
你不能简单地假设所有的连接会无限期地保持打开状态，因为另一端可能会随意关闭它们，或者可能发生网络故障，迫使它们关闭。
当你尝试读取或写入一个已关闭的连接时，会出现错误信息：
"使用已关闭的网络连接"
你应该丢弃已关闭的连接。
英文:
You cannot simply assume all connections to stay open indefinitely because the other end may close them at will or a network outage may occur, forcing them to close as well.
When you try to read or write to a closed connection, you get an error
"use of closed network connection"
You should discard closed connections.
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