go实现聊天室功能

初学golang，发现语言层面真的和php不太一样，不过学习上没有特别大的困难，这个小案例也算一个学习心得，以下代码并不是自己去实现的，我只是做了相关的整理，去理解总体的实现流程逻辑

实现效果如下图所示：

整体的逻辑如下，hub结构体中存储着聊天室所有的connection用户连接信息，当用户登录或登出时，通过channel传递信息，将hub结构体中的用户连接信息添加或删除。每当有用户连接时，服务端会新增一个协程，保持对应连接，并分别创建数据读取器和数据写入器，针对该websocket进行读取和写入。

在通信协议上，使用了websocket协议，它的最大特点就是，服务器可以主动向客户端推送信息，客户端也可以主动向服务器发送信息，是真正的双向平等对话，属于服务器推送技术的一种。websocket协议在实现上基于http协议，通过Upgrade将协议升级。

服务端代码实现(已添加注释可放心阅读)：

server.go

package main

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

    "github.com/gorilla/mux"
)

func main() {
    router := mux.NewRouter()
    //开启协程启动connection服务管理中心
    go h.run()
    //创建ws服务
    router.HandleFunc("/ws", myws)
    //启动http服务
    if err := http.ListenAndServe("127.0.0.1:8080", router); err != nil {
        fmt.Println("err:", err)
    }
}

//用户中心，维护多个用户的connection
var h = hub{
    c: make(map[*connection]bool),
    u: make(chan *connection),
    b: make(chan []byte),
    r: make(chan *connection),
}

type hub struct {
    //当前在线connection信息
    c map[*connection]bool
    //删除connection
    u chan *connection
    //传递数据
    b chan []byte
    //加入connection
    r chan *connection
}

func (h *hub) run() {
    for {
        select {
        //用户连接，添加connection信息
        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)
            //发送给写入器
            c.sc <- data_b
        //删除指定用户连接
        case c := <-h.u:
            if _, ok := h.c[c]; ok {
                delete(h.c, c)
                close(c.sc)
            }
        //向聊天室在线人员发送信息
        case data := <-h.b:
            for c := range h.c {
                select {
                //发送数据
                case c.sc <- data:
                //发送不成功则删除connection信息
                default:
                    delete(h.c, c)
                    close(c.sc)
                }
            }
        }
    }
}

connection.go

package main

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

    "github.com/gorilla/websocket"
)

//用户连接结构体
type connection struct {
    ws   *websocket.Conn
    sc   chan []byte
    data *Data
}

//用户在线名单列表
var user_list = []string{}

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"`
}

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

//websocket服务
func myws(w http.ResponseWriter, r *http.Request) {
    //协议升级
    ws, err := wu.Upgrade(w, r, nil)
    if err != nil {
        return
    }
    //创建连接
    c := &connection{sc: make(chan []byte, 256), ws: ws, data: &Data{}}
    //connection加入hub管理
    h.r <- c
    go c.writer()
    c.reader()
    //退出登录
    defer logout(c)
}
//数据写入器
func (c *connection) writer() {
    //取出发送信息并写入
    for message := range c.sc {
        fmt.Println(message,"\n")
        c.ws.WriteMessage(websocket.TextMessage, message)
    }
    c.ws.Close()
}

//数据读取器
func (c *connection) reader() {
    for {
        //接收ws信息
        _, message, err := c.ws.ReadMessage()
        if err != nil {
            h.r <- c
            break
        }
        json.Unmarshal(message, &c.data)
        //解析信息类型
        switch c.data.Type {
        //用户登录
        case "login":
            c.data.User = c.data.Content
            c.data.From = c.data.User
            //在线人数增加
            user_list = append(user_list, c.data.User)
            c.data.UserList = user_list
            data_b, _ := json.Marshal(c.data)
            //发送信息
            h.b <- data_b
        case "user":
            c.data.Type = "user"
            data_b, _ := json.Marshal(c.data)
            h.b <- data_b
        //用户登出
        case "logout":
            c.data.Type = "logout"
            //在线人数减少
            user_list = del(user_list, c.data.User)
            data_b, _ := json.Marshal(c.data)
            //删除连接
            h.b <- data_b
            //发送用户离线信息
            h.r <- c
        default:
            fmt.Print("========default================")
        }
    }
}

//删除登出的用户，维护在线用户名单
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
        }
    }
    return n_slice
}

//退出
func logout(c *connection){
    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
}

客户端代码实现：

<!DOCTYPE html>
<html>
<head>
    <title></title>
    <meta http-equiv="content-type" content="text/html;charset=utf-8">
    <style>
        p {
            text-align: left;
            padding-left: 20px;
        }
    </style>
</head>
<body>
<div style="width: 800px;height: 600px;margin: 30px auto;text-align: center">
    <div style="width: 800px;border: 1px solid gray;height: 300px;">
        <div style="width: 200px;height: 300px;float: left;text-align: left;">
            <p><span>当前在线:</span><span id="user_num">0</span></p>
            <div id="user_list" style="overflow: auto;">
            </div>
        </div>
        <div id="msg_list" style="width: 598px;border:  1px solid gray; height: 300px;overflow: scroll;float: left;">
        </div>
    </div>
    <br>
    <textarea id="msg_box" rows="6" cols="50" onkeydown="confirm(event)"></textarea><br>
    <input type="button" value="发送" onclick="send()">
</div>
</body>
</html>
<script type="text/javascript">
    var uname = prompt('请输入用户名', 'user' + uuid(8, 16));
    var ws = new WebSocket("ws://127.0.0.1:8080/ws");
    ws.onopen = function () {
        var data = "系统消息：建立连接成功";
        listMsg(data);
    };
    ws.onmessage = function (e) {
        var msg = JSON.parse(e.data);
        var sender, user_name, name_list, change_type;
        switch (msg.type) {
            case 'system':
                sender = '系统消息: ';
                break;
            case 'user':
                sender = msg.from + ': ';
                break;
            case 'handshake':
                var user_info = {'type': 'login', 'content': uname};
                sendMsg(user_info);
                return;
            case 'login':
            case 'logout':
                user_name = msg.content;
                name_list = msg.user_list;
                change_type = msg.type;
                dealUser(user_name, change_type, name_list);
                return;
        }
        var data = sender + msg.content;
        listMsg(data);
    };
    ws.onerror = function () {
        var data = "系统消息 : 出错了,请退出重试.";
        listMsg(data);
    };
    function confirm(event) {
        var key_num = event.keyCode;
        if (13 == key_num) {
            send();
        } else {
            return false;
        }
    }
    function send() {
        var msg_box = document.getElementById("msg_box");
        var content = msg_box.value;
        var reg = new RegExp("\r\n", "g");
        content = content.replace(reg, "");
        var msg = {'content': content.trim(), 'type': 'user'};
        sendMsg(msg);
        msg_box.value = '';
    }
    function listMsg(data) {
        var msg_list = document.getElementById("msg_list");
        var msg = document.createElement("p");
        msg.innerHTML = data;
        msg_list.appendChild(msg);
        msg_list.scrollTop = msg_list.scrollHeight;
    }
    function dealUser(user_name, type, name_list) {
        var user_list = document.getElementById("user_list");
        var user_num = document.getElementById("user_num");
        while(user_list.hasChildNodes()) {
            user_list.removeChild(user_list.firstChild);
        }
        for (var index in name_list) {
            var user = document.createElement("p");
            user.innerHTML = name_list[index];
            user_list.appendChild(user);
        }
        user_num.innerHTML = name_list.length;
        user_list.scrollTop = user_list.scrollHeight;
        var change = type == 'login' ? '上线' : '下线';
        var data = '系统消息: ' + user_name + ' 已' + change;
        listMsg(data);
    }
    function sendMsg(msg) {
        var data = JSON.stringify(msg);
        ws.send(data);
    }
    function uuid(len, radix) {
        var chars = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'.split('');
        var uuid = [], i;
        radix = radix || chars.length;
        if (len) {
            for (i = 0; i < len; i++) uuid[i] = chars[0 | Math.random() * radix];
        } else {
            var r;
            uuid[8] = uuid[13] = uuid[18] = uuid[23] = '-';
            uuid[14] = '4';
            for (i = 0; i < 36; i++) {
                if (!uuid[i]) {
                    r = 0 | Math.random() * 16;
                    uuid[i] = chars[(i == 19) ? (r & 0x3) | 0x8 : r];
                }
            }
        }
        return uuid.join('');
    }
</script>

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