Solving data loss issues in Go language Websocket applications

In Go language Websocket applications, data loss is a common problem. Since Websocket uses an asynchronous transmission method, data packets may be lost or damaged during transmission. In this case, how to solve the problem of data loss is a challenge that every developer needs to face.

This article will introduce some methods to solve the problem of data loss in Go language Websocket applications, and provide specific code examples so that readers can quickly understand how to deal with these problems.

1. Using the cache area

In Websocket applications, you can use the cache area to save data so that if the data is lost during transmission, it can be retransmitted in time. In Go language, you can use channels as buffer areas. The following is a sample code that uses channel as the buffer area:

func readPump(conn *websocket.Conn, ch chan []byte) {
    for {
        _, message, err := conn.ReadMessage()
        if err != nil {
            break
        }
        ch <- message
    }
    close(ch)
}

func writePump(conn *websocket.Conn, ch chan []byte) {
    for message := range ch {
        err := conn.WriteMessage(websocket.TextMessage, message)
        if err != nil {
            break
        }
    }
    conn.Close()
}

func main() {
    ch := make(chan []byte, 10)

    // 启动读取协程
    go readPump(conn, ch)

    // 启动写入协程
    go writePump(conn, ch)
}

In this code, the readPump function will save the read message to the buffer area ch; the writePump function will read from the buffer area ch. message and written to the connection. If a message is lost during transmission, it is saved in the buffer for retransmission.

2. Implementing data fragmentation

In Websocket applications, the size of data packets is limited. If the size of the data packet exceeds the limit, it will be cut into Multiple small packets are transmitted. In order to avoid data loss, data fragmentation can be implemented in the application to cut the data packet into multiple small data fragments for transmission. The following is a sample code to implement data fragmentation:

func writeMessage(conn *websocket.Conn, message []byte) error {
    messageSize := len(message)
    if messageSize > maxMessageSize {
        return errors.New("Message too large")
    }

    // 计算分片数量
    fragmentSize := (messageSize / maxFragmentSize) + 1

    for i := 0; i < fragmentSize; i++ {
        start := i * maxFragmentSize
        end := start + maxFragmentSize

        // 切割数据片段
        if end > messageSize {
            end = messageSize
        }
        fragment := message[start:end]

        // 写入分片
        err := conn.WriteMessage(websocket.TextMessage, fragment)
        if err != nil {
            return err
        }
    }

    return nil
}

func main() {
    message := []byte("Hello, world!")
    err := writeMessage(conn, message)
    if err != nil {
        log.Println(err)
    }
}

In this code, the writeMessage function will cut the message into multiple data fragments for transmission. If a message is lost in transit, only partial data fragments are lost, not the entire message.

3. Implementing data packet verification

In Websocket applications, in order to avoid errors in data packets during transmission, data packets can be verified. Verification information can be added to the data packet. After receiving the data packet, the receiver will verify it based on the verification information. If the verification fails, the sender will be asked to resend the data packet. The following is a sample code to implement data packet verification:

type Message struct {
    ID    int    `json:"id"`
    Data  []byte `json:"data"`
    Checksum uint16 `json:"checksum"`
}

func writeMessage(conn *websocket.Conn, message Message) error {
    // 计算校验和
    checksum := calculateChecksum(message.Data)

    // 添加校验和信息
    message.Checksum = checksum

    // 序列化消息
    body, err := json.Marshal(message)
    if err != nil {
        return err
    }

    // 发送消息
    err = conn.WriteMessage(websocket.TextMessage, body)
    if err != nil {
        return err
    }

    return nil
}

func readMessage(conn *websocket.Conn) (Message, error) {
    var message Message

    // 接收消息
    _, body, err := conn.ReadMessage()
    if err != nil {
        return message, err
    }

    // 反序列化消息
    err = json.Unmarshal(body, &message)
    if err != nil {
        return message, err
    }

    // 校验消息
    if message.Checksum != calculateChecksum(message.Data) {
        return message, errors.New("Checksum error")
    }

    return message, nil
}

func calculateChecksum(data []byte) uint16 {
    checksum := uint16(0)
    for i := 0; i < len(data); i++ {
        checksum += uint16(data[i])
    }
    return checksum
}

func main() {
    message := Message{
        ID:   1,
        Data: []byte("Hello, world!"),
    }
    err := writeMessage(conn, message)
    if err != nil {
        log.Println(err)
    }

    rcvMessage, err := readMessage(conn)
    if err != nil {
        log.Println(err)
    } else {
        log.Println(rcvMessage)
    }
}

In this code, the writeMessage function will add the checksum information to the data packet, and the readMessage function will after receiving the data packet, based on the verification and verify. If the checksums do not match, the packet was lost or altered during transmission.

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