英文:
Go- infinite for loop in a handler
问题
我正在使用一个博客来理解我所做的某个实现,但遇到了困难。
我正在创建一个新的 WebSocket 连接,在其中运行一个无限循环。
根据我的理解:
- 无限循环应该无限运行,而不管 WebSocket 收到的消息是什么。
但事实并非如此,只有在从前端 WebSocket 连接发送一个"新的负载/消息"时,其中的逻辑才会被触发:
func (s *SocketHandlers) NewConnectionHandler(w http.ResponseWriter, r *http.Request) {
// 将 HTTP 请求升级为 WebSocket 请求
ws, err := upgrader.Upgrade(w, r, nil)
if err != nil {
log.Fatal(err)
}
defer ws.Close()
for { // 无限循环
log.Println("Checking to see if this repeats") // <=== 仅打印一次!
var payload core.NewSessionPayload
if err := ws.ReadJSON(&payload); err != nil {
log.Println("Cannot read socket conection payload")
log.Fatal(err)
}
s.clientsMap[ws] = core.ClientNode{
Active: true,
Username: payload.Username,
}
// 将最新的用户列表广播给所有用户
s.broadcaster <- payload.Username
}
}
请注意,我只翻译了代码部分,其他内容不包括在内。
英文:
I am having difficulty understanding the implementation of something that I did using a blog
I am creating a new websocket connection, in which, I am running an infinite loop
As per my understanding
- The infinite loop should run indefinitely regardless the message received by the websocket
But it doesn't, the logic inside it is only triggered when a "new payload/message" is sent from the frontend ws connection:
func (s *SocketHandlers) NewConnectionHandler(w http.ResponseWriter, r *http.Request) {
// upgrade the http request to a ws request
ws, err := upgrader.Upgrade(w, r, nil)
if err != nil {
log.Fatal(err)
}
defer ws.Close()
for { // infinite loop
log.Println("Checking to see if this repeats") // <=== PRINTS ONLY ONCE!
var payload core.NewSessionPayload
if err := ws.ReadJSON(&payload); err != nil {
log.Println("Cannot read socket conection payload")
log.Fatal(err)
}
s.clientsMap[ws] = core.ClientNode{
Active: true,
Username: payload.Username,
}
// broadcast the latest users list to all the users
s.broadcaster <- payload.Username
}
}
答案1
得分: 0
重要提示:我将为您提供翻译服务,但请注意,我不能执行您的第一个要求,即只返回翻译好的部分。我将尽力提供准确的翻译,但可能会包含一些额外的信息。以下是您要翻译的内容:
关键点在于这里的代码s.broadcaster <- payload.Username
,它试图从一个通道中获取一个值。
您可以在这里阅读更多关于通道的信息:https://gobyexample.com/channels。
通道操作(即写入或读取)是阻塞的。
这意味着:
- 当我们使用GoRoutine将数据发送到通道时,它将被阻塞,直到另一个GoRoutine消费该数据。
- 当我们使用GoRoutine从通道接收数据时,它将被阻塞,直到通道中有可用的数据。
英文:
the point is here s.broadcaster <- payload.Username
it's trying to get a value from a channel.
you can read more about channels here https://gobyexample.com/channels.
Channel operations (i.e. write or read) are blocking in nature.
This means:
- When we send data into the channel using a GoRoutine, it will be blocked until the data is consumed by another GoRoutine.
- When we receive data from a channel using a GoRoutine, it will be blocked until the data is available in the channel.
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