go - Sec-Websocket-Protocol issues

Question

I am facing an issue with Go while using the WebSockets protocol. If I connect to my API, everything works fine. If I add "protocol" such as "Hey", it begins to loop multiple times and finishes by getting an error *github.com/gorilla/websocket.CloseError: "Code 1006, Text Unexpected EOF".

I definitely don't get why it acts like this when I send Sec-Websocket-Protocol among the connection.

There is my code:

main.go

package main

import (
    "fmt"
    "github.com/golang/glog"
    "github.com/grpc-ecosystem/grpc-gateway/runtime"
    stacktracer "gitlab.com/eyes-eyes/internals-stacktracer"
    "gitlab.com/eyesbank/go-web-sockets-server/handlers"
    "net/http"
)

const webSocketsAddr = "0.0.0.0:8082"

// main is the starting point of the current micro service.
func main() {

    // Setting the service name
    stacktracer.SetServiceName("Hello 'X' (Web Sockets)")

    // Initializing the HTTP errors handling
    runtime.HTTPError = stacktracer.DefaultHTTPError

    if err := RunWebSocketsServer(); err != nil {
        glog.Fatal(err)
    }

}

//
// WebSocket
//

func RunWebSocketsServer() error {

    http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
        handlers.HandleUserSocket(w, r)
    })

    fmt.Println(webSocketsAddr)

    return http.ListenAndServe(webSocketsAddr, nil)
}

func RunWebSocketsTLSServer() error {

    http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
        handlers.HandleUserSocket(w, r)
    })

    fmt.Println(webSocketsAddr)

    return http.ListenAndServeTLS(webSocketsAddr, "server.crt", "server.key", nil)
}

handler.go

package handlers

import (
    "fmt"
    "github.com/gorilla/websocket"
    stacktracer "gitlab.com/eyes-eyes/internals-stacktracer"
    "gitlab.com/eyes-eyes/internals-stacktracer/structs"
    "go.mongodb.org/mongo-driver/bson/primitive"
    "log"
    "net/http"
)

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

func HandleUserSocket(w http.ResponseWriter, r *http.Request) {

    var userID = primitive.NewObjectID()
    conn, err := upgrader.Upgrade(w, r, nil) // error ignored for sake of simplicity
    if err != nil {
        log.Fatalf("failed to listen: %v", err)
    } else {
        WriteOutgoingMessage(conn, "Welcome "+userID.Hex())
    }

    fmt.Println(r.Header["Sec-Websocket-Protocol"])
    if len(r.Header["Sec-Websocket-Protocol"]) > 0 {
        WriteOutgoingMessage(conn, userID.Hex() + " " + string(r.Header["Sec-Websocket-Protocol"][0]))
    }

    for {
        // Read message from browser
        _, msg, err := conn.ReadMessage()
        if err != nil {
            if err != nil {
                switch err.(type) {
                case *websocket.CloseError:
                    fmt.Println("disconnected")
                    return
                default:
                    _ = conn.WriteMessage(websocket.TextMessage, []byte(err.Error()))
                    fmt.Println(err.Error())
                    fmt.Println("disconnected")
                    return
                }
            }
        }

        if msg != nil {
            WriteOutgoingMessage(conn, userID.Hex() + " " + string(msg))
        }
    }
}

func WriteOutgoingMessage(conn *websocket.Conn, message string) *structs.StackTrace {

    // Write message back to browser
    if err := conn.WriteMessage(websocket.TextMessage, []byte("Got: \""+message+"\"")); err != nil {
        err = conn.WriteMessage(websocket.TextMessage, []byte(err.Error()))
        if err != nil {
            return stacktracer.NewStackTrace(500, err.Error(), nil)
        }
    }

    return nil

}

标签： gowebsocketprotocolsgorilla

Answer 1

如果客户端请求子协议并且服务器不同意这些子协议之一，则客户端需要关闭连接。客户端使用 Sec-Websocket-Protocol 标头来请求一个或多个子协议。服务器使用 Sec-Websocket-Protocol 响应头来同意协议。有关此主题的更多信息，请参阅RFC。

通过同意客户端请求的协议之一来解决问题。有几种方法可以做到这一点。

首先是使用内置的协议协商功能：

var upgrader = websocket.Upgrader{
    ReadBufferSize:  1024,
    WriteBufferSize: 1024,
    Subprotocols: []string{ "hey" },  // <-- add this line
    CheckOrigin: func(r *http.Request) bool {
        return true
    },
}

第二种是在调用 Upgrade 之前协商应用程序代码中的协议。调用websocket.Subprotocols以获取请求的协议，选择其中一种协议并在 Upgrade 的标头参数中指定该协议。

h := http.Header{}
for _, sub := range websocket.Subprotocols(req) {
   if sub == "hey" {
      h.Set("Sec-Websocket-Protocol", "hey")
      break
   }
}
conn, err := upgrader.Upgrade(w, r, h)

与此问题不同，应用程序应该defer conn.Close()在成功升级后。

此外，可以简化错误处理逻辑。应用程序应在 ReadMessage 返回的任何错误上退出读取循环。在连接错误之后写消息是没有意义的。ReadMessage 方法在成功时返回非零消息。

for {
    // Read message from browser
    _, msg, err := conn.ReadMessage()
    if err != nil {
         fmt.Println(err.Error())
          fmt.Println("disconnected")
          return
    }
    WriteOutgoingMessage(conn, userID.Hex() + " " + string(msg))
}