我无法用自动收报机逃避 for 循环

Question

我有这个 API 可以扫描驱动程序的位置并每 1 秒通过 web-socket 发送它们。问题是客户端断开连接时无法逃脱循环。它似乎永远活着。我正在将 Gin 与 nhooyr websocket 库一起使用。var GetDriverLocations = func(c *gin.Context) {    wsoptions := websocket.AcceptOptions{InsecureSkipVerify: true}    wsconn, err := websocket.Accept(c.Writer, c.Request, &wsoptions)    if err != nil {        return    }    defer wsconn.Close(websocket.StatusInternalError, "the sky is falling")    driverLocation := &models.DriverLocation{}    ticker := time.NewTicker(time.Second)    defer ticker.Stop()    for {        select {        case <-ticker.C:        case <-c.Request.Context().Done():            fmt.Println("done") //this never gets printed            return        }        coords, err := driverLocation.GetDrivers()        if err != nil {            break        }        err = wsjson.Write(c.Request.Context(), wsconn, &coords)        if websocket.CloseStatus(err) == websocket.StatusNormalClosure {            break        }        if err != nil {            break        }    }    fmt.Println("conn ended") //this never gets printed}我也试过这个循环，但也有同样的问题：for range ticker.C{    coords, err := driverLocation.GetDrivers()    if err != nil {        break    }    err = wsjson.Write(c.Request.Context(), wsconn, &coords)    if websocket.CloseStatus(err) == websocket.StatusNormalClosure {        break    }    if err != nil {        break    }}

Answer 1

因为网络连接被 nhooyr websocket 库从 net/http 服务器劫持，所以在c.Request.Context()处理程序返回之前不会取消上下文。

调用CloseRead以获取在连接关闭时取消的上下文。在循环中使用该上下文。

var GetDriverLocations = func(c *gin.Context) {

    wsoptions := websocket.AcceptOptions{InsecureSkipVerify: true}

    wsconn, err := websocket.Accept(c.Writer, c.Request, &wsoptions)

    if err != nil {

        return

    }

    defer wsconn.Close(websocket.StatusInternalError, "")

    ctx := wsconn.CloseRead(c.Request.Context())

    driverLocation := &models.DriverLocation{}

    ticker := time.NewTicker(time.Second)

    defer ticker.Stop()

    for {

        select {

        case <-ticker.C:

        case <-ctx.Done():

            return

        }

        coords, err := driverLocation.GetDrivers()

        if err != nil {

            break

        }

        err = wsjson.Write(c.Request.Context(), wsconn, &coords)

        if err != nil {

            break

        }

    }

}