Golang网络编程如何实现TCP粘包处理 分享自定义协议与编解码方案

[长度字段][消息体]

conn, _ := listener.Accept()
reader := bufio.NewReader(conn)
scanner := bufio.NewScanner(reader)

// 设置自定义分割函数（可选）
// scanner.Split(bufio.ScanLines) // 默认按行切割

for scanner.Scan() {
    fmt.Println("收到消息：", scanner.Text())
}

var buf bytes.Buffer
for {
    tmp := make([]byte, 4096)
    n, err := conn.Read(tmp)
    if err != nil {
        break
    }
    buf.Write(tmp[:n])

    for {
        if buf.Len() < 4 {
            break
        }

        length := binary.BigEndian.Uint32(buf.Next(4))
        if uint32(buf.Len()) < length {
            // 数据不够，回退4字节
            buf.Truncate(0)
            buf.Write(tmp[:4])
            break
        }

        message := buf.Next(int(length))
        // 处理message...
    }
}

type MessageCodec struct {
    buffer bytes.Buffer
}

func (c *MessageCodec) Encode(data []byte) []byte {
    buf := new(bytes.Buffer)
    binary.Write(buf, binary.BigEndian, uint32(len(data)))
    buf.Write(data)
    return buf.Bytes()
}

func (c *MessageCodec) Decode(input []byte) [][]byte {
    c.buffer.Write(input)
    var messages [][]byte

    for {
        if c.buffer.Len() < 4 {
            break
        }

        length := binary.BigEndian.Uint32(c.buffer.Next(4))
        if uint32(c.buffer.Len()) < length {
            c.buffer.Truncate(0)
            c.buffer.Write(c.buffer.Next(4)) // 回退
            break
        }

        msg := c.buffer.Next(int(length))
        messages = append(messages, msg)
    }

    return messages
}