cannot use ccc (type int) as type *websocket.Conn in argument to websocket.Message.Send

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英文:

cannot use ccc (type int) as type *websocket.Conn in argument to websocket.Message.Send

问题

我正在尝试使用Websockets向客户端发送广播消息。如何修复这段代码,以便正确地向所有客户端发送消息并消除错误?

package main

import (
	"fmt"
	"golang.org/x/net/websocket"
	"net/http"
)

var connections []websocket.Conn

func main() {
	fmt.Println("vim-go")
	http.Handle("/", websocket.Handler(Server))
	err := http.ListenAndServe(":8888", nil)
	if err != nil {
		panic("ListenAndServe: " + err.Error())
	}
}

func Server(ws *websocket.Conn) {
	connections = append(connections, *ws)
	var message string
	websocket.Message.Receive(ws, &message)
	fmt.Println(message)
	for _, ccc := range connections {
		websocket.Message.Send(&ccc, "Another connection!!!")
	}
}

这段代码存在几个问题。首先,connections变量应该是一个指向websocket.Conn的切片,而不是websocket.Conn的切片。所以,你需要将connections的类型更改为[]*websocket.Conn

其次,在Server函数中,你应该使用range关键字来遍历connections切片,而不是使用range关键字的索引。这样可以直接获取到每个连接。

最后,在发送消息时,你应该使用连接的指针作为参数,而不是连接本身。所以,你需要将websocket.Message.Send(ccc, "Another connection!!!")更改为websocket.Message.Send(&ccc, "Another connection!!!")

修复后的代码如上所示。希望能帮到你!

英文:

I am trying to send a broadcast message to clients using websockets. How to fix this code to send message properly to all clients and without that error?

package main

import (
	"fmt"
	"golang.org/x/net/websocket"
	"net/http"
)

var connections []websocket.Conn

func main() {
	fmt.Println("vim-go")
	http.Handle("/", websocket.Handler(Server))
	err := http.ListenAndServe(":8888", nil)
	if err != nil {
		panic("ListenAndServe: " + err.Error())
	}
}

func Server(ws *websocket.Conn) {
	lll := append(connections, *ws)
	var message string
	websocket.Message.Receive(ws, &message)
	fmt.Println(message)
	for ccc := range connections {
		websocket.Message.Send(ccc, "Another connection!!!")
	}
}

答案1

得分: 1

不确定你在使用lll时想要做什么,但是如果不使用它,你的代码应该无法编译。


当在:=的左侧使用单个迭代变量对切片/数组进行迭代时,它将被赋予迭代的索引。所以在你的例子中,ccc就是索引。

你可以这样做:

for ccc := range connections {
    websocket.Message.Send(connections[ccc], "Another connection!!!")
}

但是你可能真正想要的是,丢弃索引并立即获取元素,你可以使用两个迭代变量,如果你根本不打算使用索引,可以将第一个迭代变量设为_

for _, ccc := range connections {
    websocket.Message.Send(ccc, "Another connection!!!")
}

在这里阅读更多信息:https://golang.org/ref/spec#For_range

英文:

Not sure what you're trying to do with lll but without using it your code should not event compile.


When rangeing over slices/arrays with a single iteration variable on the left of := it will be assigned the index of the iteration. So in your case ccc is the index.

One thing you can do is:

for ccc := range connections {
    websocket.Message.Send(connections[ccc], "Another connection!!!")
}

But what you probably really want is, drop the index and get the element right away which you can do using two iteration variables with the _ as the first one if you don't inted to use the index at all.

for _, ccc := range connections {
    websocket.Message.Send(ccc, "Another connection!!!")
}

read more here: https://golang.org/ref/spec#For_range

huangapple
  • 本文由 发表于 2017年8月26日 11:58:53
  • 转载请务必保留本文链接:https://go.coder-hub.com/45891799.html
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