go语言WebSocket编程

1. webSocket介绍

• WebSocket是一种在单个TCP连接上进行全双工通信的协议
• WebSocket使得客户端和服务器之间的数据交换变得更加简单，允许服务端主动向客户端推送数据
• 在WebSocket API中，浏览器和服务器只需要完成一次握手，两者之间就直接可以创建持久性的连接，并进行双向数据传输
• 需要安装第三方包：
  • cmd中：go get -u -v github.com/gorilla/websocket

2. 实例

在同一级目录下新建四个go文件connection.go|data.go|hub.go|server.go

运行

    go run server.go hub.go data.go connection.go

运行之后执行local.html文件

server.go文件代码

package main

import (
    "fmt"
    "net/http"

    "github.com/gorilla/mux"
)

func main() {
    router := mux.NewRouter()
    go h.run()
    router.HandleFunc("/ws", myws)
    if err := http.ListenAndServe("127.0.0.1:8080", router); err != nil {
        fmt.Println("err:", err)
    }
}

hub.go文件代码

package main

import "encoding/json"

var h = hub{
    c: make(map[*connection]bool),
    u: make(chan *connection),
    b: make(chan []byte),
    r: make(chan *connection),
}

type hub struct {
    c map[*connection]bool
    b chan []byte
    r chan *connection
    u chan *connection
}

func (h *hub) run() {
    for {
        select {
        case c := <-h.r:
            h.c[c] = true
            c.data.Ip = c.ws.RemoteAddr().String()
            c.data.Type = "handshake"
            c.data.UserList = user_list
            data_b, _ := json.Marshal(c.data)
            c.sc <- data_b
        case c := <-h.u:
            if _, ok := h.c[c]; ok {
                delete(h.c, c)
                close(c.sc)
            }
        case data := <-h.b:
            for c := range h.c {
                select {
                case c.sc <- data:
                default:
                    delete(h.c, c)
                    close(c.sc)
                }
            }
        }
    }
}

data.go文件代码

package main

type Data struct {
    Ip       string   `json:"ip"`
    User     string   `json:"user"`
    From     string   `json:"from"`
    Type     string   `json:"type"`
    Content  string   `json:"content"`
    UserList []string `json:"user_list"`
}

connection.go文件代码

package main

import (
    "encoding/json"
    "fmt"
    "net/http"

    "github.com/gorilla/websocket"
)

type connection struct {
    ws   *websocket.Conn
    sc   chan []byte
    data *Data
}

var wu = &websocket.Upgrader{ReadBufferSize: 512,
    WriteBufferSize: 512, CheckOrigin: func(r *http.Request) bool { return true }}

func myws(w http.ResponseWriter, r *http.Request) {
    ws, err := wu.Upgrade(w, r, nil)
    if err != nil {
        return
    }
    c := &connection{sc: make(chan []byte, 256), ws: ws, data: &Data{}}
    h.r <- c
    go c.writer()
    c.reader()
    defer func() {
        c.data.Type = "logout"
        user_list = del(user_list, c.data.User)
        c.data.UserList = user_list
        c.data.Content = c.data.User
        data_b, _ := json.Marshal(c.data)
        h.b <- data_b
        h.r <- c
    }()
}

func (c *connection) writer() {
    for message := range c.sc {
        c.ws.WriteMessage(websocket.TextMessage, message)
    }
    c.ws.Close()
}

var user_list = []string{}

func (c *connection) reader() {
    for {
        _, message, err := c.ws.ReadMessage()
        if err != nil {
            h.r <- c
            break
        }
        json.Unmarshal(message, &c.data)
        switch c.data.Type {
        case "login":
            c.data.User = c.data.Content
            c.data.From = c.data.User
            user_list = append(user_list, c.data.User)
            c.data.UserList = user_list
            data_b, _ := json.Marshal(c.data)
            h.b <- data_b
        case "user":
            c.data.Type = "user"
            data_b, _ := json.Marshal(c.data)
            h.b <- data_b
        case "logout":
            c.data.Type = "logout"
            user_list = del(user_list, c.data.User)
            data_b, _ := json.Marshal(c.data)
            h.b <- data_b
            h.r <- c
        default:
            fmt.Print("========default================")
        }
    }
}

func del(slice []string, user string) []string {
    count := len(slice)
    if count == 0 {
        return slice
    }
    if count == 1 && slice[0] == user {
        return []string{}
    }
    var n_slice = []string{}
    for i := range slice {
        if slice[i] == user && i == count {
            return slice[:count]
        } else if slice[i] == user {
            n_slice = append(slice[:i], slice[i+1:]...)
            break
        }
    }
    fmt.Println(n_slice)
    return n_slice
}

local.html文件代码

    
    
    



    
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