Golang 高性能实时通信系统后端：WebSocket + MongoDB

以下是一个简单的基于 WebSocket 协议、使用 MongoDB 数据库的高性能即时通信系统后端的 Golang 实现：

安装依赖库

go get github.com/gorilla/websocket
go get gopkg.in/mgo.v2
go get gopkg.in/mgo.v2/bson

初始化 MongoDB 连接

import "gopkg.in/mgo.v2"

func init() {
    session, err := mgo.Dial("mongodb://localhost:27017")
    if err != nil {
        panic(err)
    }

    // optional. switch the session to a monotonic behavior.
    session.SetMode(mgo.Monotonic, true)

    // set the global variable
    db = session.DB("mydb")
}

定义 WebSocket 处理函数

import (
    "github.com/gorilla/websocket"
    "time"
)

var upgrader = websocket.Upgrader{
    ReadBufferSize:  1024,
    WriteBufferSize: 1024,
    CheckOrigin: func(r *http.Request) bool {
        return true
    },
}

type Message struct {
    Username string `json:'username' `
    Content  string `json:'content' `
}

func websocketHandler(w http.ResponseWriter, r *http.Request) {
    conn, err := upgrader.Upgrade(w, r, nil)
    if err != nil {
        log.Println(err)
        return
    }

    // read message from client
    for {
        var msg Message
        err := conn.ReadJSON(&msg)
        if err != nil {
            log.Println(err)
            break
        }

        // save message to MongoDB
        msg.Time = time.Now()
        err = db.C("messages").Insert(&msg)
        if err != nil {
            log.Println(err)
            break
        }

        // broadcast message to all clients
        broadcast(&msg)
    }

    conn.Close()
}

定义广播函数

import (
    "github.com/gorilla/websocket"
    "gopkg.in/mgo.v2"
    "gopkg.in/mgo.v2/bson"
)

type Message struct {
    ID       bson.ObjectId `bson:'_id,omitempty' `
    Username string        `json:'username' `
    Content  string        `json:'content' `
    Time     time.Time     `json:'time' `
}

var clients = make(map[*websocket.Conn]bool) // connected clients
var broadcast = make(chan Message)           // broadcast channel

func handleMessages() {
    for {
        // grab the next message from the broadcast channel
        msg := <-broadcast

        // send it out to every client that is currently connected
        for client := range clients {
            err := client.WriteJSON(msg)
            if err != nil {
                log.Println(err)
                client.Close()
                delete(clients, client)
            }
        }
    }
}

启动服务器

func main() {
    // handle incoming websocket connections
    http.HandleFunc("/ws", websocketHandler)

    // start the broadcast loop
    go handleMessages()

    // start the server
    log.Println("Starting server...")
    err := http.ListenAndServe(":8000", nil)
    if err != nil {
        log.Fatal("ListenAndServe: ", err)
    }
}

这只是一个简单的示例，实际应用中可能需要更多的功能，例如身份验证、房间管理等等。