Golang websocket

2024-02-05 21:47

短信预约 -IT技能 免费直播动态提醒

问题内容

谁能帮忙解释一下下面的代码片段的含义吗？

var partner = make(chan io.ReadWriteCloser)

func match(c io.ReadWriteCloser) {
    fmt.Fprintln(c, "Waiting for a partner...")
    select {
    case partner <- c:
        // handled by the other goroutine
    case p := <-partner:
        chat(p, c)
    }
}

完整版：

package main

import (
    "fmt"
    "golang.org/x/net/websocket"
    "html/template"
    "io"
    "log"
    "net/http"
)

const listenAddr = "localhost:4000"

type socket struct {
    conn *websocket.Conn
    done chan bool
}

func (s socket) Read(b []byte) (int, error) {
    return s.conn.Read(b)
}

func (s socket) Write(b []byte) (int, error) {
    return s.conn.Write(b)
}

func (s socket) Close() error {
    s.done <- true
    return nil
}

var rootTemplate = template.Must(template.New("root").Parse(`


    
        Websocket Chat - Golang
        
        
    
    
        Say: 
        
    

`))

func rootHandler(w http.ResponseWriter, r *http.Request) {
    rootTemplate.Execute(w, listenAddr)
}

func socketHandler(conn *websocket.Conn) {
    s := socket{conn: conn, done: make(chan bool)}
    go match(s)
    <-s.done
}

var partner = make(chan io.ReadWriteCloser)

func match(c io.ReadWriteCloser) {
    fmt.Fprintln(c, "Waiting for a partner...")
    select {
    case partner <- c:
        // handled by the other goroutine
    case p := <-partner:
        chat(p, c)
    }
}

func chat(a, b io.ReadWriteCloser) {
    fmt.Fprintln(a, "Found one! Say hi.")
    fmt.Fprintln(b, "Found one! Say hi.")
    errc := make(chan error, 1)
    go cp(a, b, errc)
    go cp(b, a, errc)
    if err := <-errc; err != nil {
        log.Println(err)
    }
    a.Close()
    b.Close()
    go io.Copy(b, a)
    io.Copy(a, b)
}

func cp(w io.Writer, r io.Reader, errc chan<- error) {
    _, err := io.Copy(w, r)
    errc <- err
}

func main() {
    http.HandleFunc("/", rootHandler)
    http.Handle("/socket", websocket.Handler(socketHandler))
    err := http.ListenAndServe(listenAddr, nil)
    if err != nil {
        log.Fatal(err)
    }
}

不太明白为什么当第二个加入者加入聊天频道时可以执行这个聊天功能。