c# - 在不使用堆栈的情况下创建精简 MQTT 发布者（操作方法）

问题描述

我之前对谷歌的研究把我带到了这个页面：https ://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html 在这里我找到了一些信息……我开始尝试。测试设置是针对当地蚊子的。到目前为止这工作（它运行没有错误），但如果我发送 PUBLISH 消息，我会断开与蚊子的连接。

[编辑] 所以最大的问题是，消息有什么问题。

short summary as far as I understood:

[|]      a Byte with High and Low 4 bits
[[|][|]] a word
{}       a complex Byte data

Message for connect:

 [1|0][0|0] … connect=1   , 0 length since no data

Message for publish:

 [3,0]{LEN}{DATA} ...
with     {LEN}=[0xxx|xxxx] with bit7=0 … for a len <127 Bytes
or       {LEN}=[1xxx|xxxx][0xxx|xxxx] with Byte1 Bit7=1 … for a len >127 Bytes and <128^2
or       {LEN}=[1xxx|xxxx][1xxx|xxxx][0xxx|xxx] with Byte1+2 Bit7=1 … for a len >127^2 Bytes and <128^3 

with     {data}=[[][]]{topic}{value}
         [[][]] = Len of topic
         {Topic}=UTF8 string (e.g. 'demo/target') as Byte
         {value}=UTF8 string (e.g. a json or a simple text like'Hello world.') as byte

您可能想知道为什么我要对实现进行硬编码……这是为了理解功能。我喜欢用一种特殊的语言在机器人系统中实现发布，这确实允许使用带有连接/断开连接/发送和接收命令的套接字到给定的地址和端口。因此，我尝试让它在 c# 中工作以采用机器人语言。

在这里您可以找到当前代码：

using System;
using System.ComponentModel;
using System.Net;
using System.Net.Sockets;
using System.Threading;

namespace TestSender
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Hello World!");
            Socket sock = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            System.Net.IPAddress ipAdd = System.Net.IPAddress.Parse("127.0.0.1");
            System.Net.IPEndPoint remoteEP = new IPEndPoint(ipAdd, 1883);
            Console.WriteLine(sock.Connected.ToString());
            sock.Connect(remoteEP);
            Console.WriteLine(sock.Connected.ToString());
            /*
             * control flags byte
             * 0   ...RETAIN 0/1 -> 0   only PUBLISH
             * 1+2 ...QOS 0,1,2 --> 0   only PUBLISH
             * 3   ...DUPe  0/1 --> 0   only PUBLISH
             */
            /* control messagetype byte 4...7 (4=low)
            0 Reserved    0   Forbidden           Reserved
            1 CONNECT     1   Client to Server    Client request to connect to Server
            2 CONNACK     2   Server to Client    Connect acknowledgment
            3 PUBLISH     3   Client to Server    
                            or Server to Client Publish message
            4 PUBACK      4   Client to Server
                            or Server to Client Publish acknowledgment
            5 PUBREC      5   Client to Server
                            or Server to Client Publish received(assured delivery part 1)
            6 PUBREL      6   Client to Server
                            or Server to Client Publish release(assured delivery part 2)
            7 PUBCOMP     7   Client to Server
                            or Server to Client Publish complete(assured delivery part 3)
            8 SUBSCRIBE   8   Client to Server    Client subscribe request
            9 SUBACK      9   Server to Client    Subscribe acknowledgment
            A UNSUBSCRIBE 10  Client to Server    Unsubscribe request
            B UNSUBACK    11  Server to Client    Unsubscribe acknowledgment
            C PINGREQ     12  Client to Server    PING request
            D PINGRESP    13  Server to Client    PING response
            E DISCONNECT  14  Client to Server    Client is disconnecting
            F Reserved    15  Forbidden           Reserved
            */
            byte bFlagConenct = 0;
            byte bFlagPublish = 0; //no dupe, QOS (at most once = 0), no retain
            byte bMessageConnect = 1;
            byte bMessageDisConnect = 14;
            byte bMessagePublish = 3;

            byte bMessageHeaderConnect  =  Convert.ToByte( 16 * bMessageConnect  + bFlagConenct);       //10h
            byte bMessageHeaderPublish = Convert.ToByte(16 * bMessagePublish + bFlagPublish);           //30h
            byte bMessageHeaderDisconnect= Convert.ToByte(16 * bMessageDisConnect+ bFlagConenct);       //E0h


            byte[] byAdress = System.Text.Encoding.ASCII.GetBytes(@"demo/Target");
            byte[] byData = System.Text.Encoding.ASCII.GetBytes("{OFF}");
            int lenAdress = byAdress.Length;
            int lenData = byData.Length;

            //get short int, unsinged
            ushort sLenAdress = Convert.ToUInt16(lenAdress);
            ushort sLenAllData = Convert.ToUInt16(lenAdress+lenData+2);

            byte[] byLenTopic = BitConverter.GetBytes(sLenAdress); //High-Low
            Array.Reverse(byLenTopic); //High-Low swap

            //convert 256 based ushort to 128based ushort
            ushort sLenMQTT_128Base=0;
            if (sLenAllData>128)
            {
                //2nd byte needed ... add 128*256
                sLenMQTT_128Base = Convert.ToUInt16( sLenAllData +  128 * 256);

            }
            else
            {
                //only one byte
                sLenMQTT_128Base = sLenAllData;
            }
            byte[] byLenMQTT;
            if (sLenMQTT_128Base > 256)
            {
                byLenMQTT = BitConverter.GetBytes(sLenMQTT_128Base); //High-Low
            }
            else
            {
                byte bLenMQTT = Convert.ToByte(sLenMQTT_128Base);
                byLenMQTT = new byte[1]; byLenMQTT[0]= bLenMQTT; //High-Low
            }

            byte[] BytesData_MQTT = new byte[1+byLenMQTT.Length + byLenTopic.Length + byAdress.Length + byData.Length];
            //set message
            BytesData_MQTT[0]= bMessageHeaderPublish;
            //copy 128Base Len
            Array.Copy(byLenMQTT, 0, BytesData_MQTT, 1, byLenMQTT.Length);
            //copy Len of Topic
            Array.Copy(byLenTopic, 0, BytesData_MQTT, 1+ byLenMQTT.Length, byLenTopic.Length);
            //copy Topic
            Array.Copy(byAdress, 0, BytesData_MQTT, 1 + byLenMQTT.Length + byLenTopic.Length, byAdress.Length);
            //copy data
            Array.Copy(byData, 0, BytesData_MQTT, 1 + byLenMQTT.Length + byLenTopic.Length + byAdress.Length, byData.Length);



            /*
             * Paket:
             * Byte1: MessageHeader
             * Byte2-x: length of message (all data, using 128 Encoding (High Byte first), 1 Byte len<128,2 (or more) Byte if bigger, bit #7 in a Byte indicating that another byte follows)
             * Content: 2 Byte: Länge des Topics (H,L, Encoding 256)
             *     followed by: Topic  (UTF8)
             *     followed by: Values to be send (UTF8)
             */

        byte[] BytesCon_MQTT = new byte[12];
        //2byte fixed header
        BytesCon_MQTT[0] = bMessageHeaderConnect;
        BytesCon_MQTT[1] = 10;
        //10+byte variable header
        BytesCon_MQTT[2] = 0;
        BytesCon_MQTT[3] = 4;
        BytesCon_MQTT[4] = System.Text.Encoding.ASCII.GetBytes("M")[0];
        BytesCon_MQTT[5] = System.Text.Encoding.ASCII.GetBytes("Q")[0];
        BytesCon_MQTT[6] = System.Text.Encoding.ASCII.GetBytes("T")[0];
        BytesCon_MQTT[7] = System.Text.Encoding.ASCII.GetBytes("T")[0];
        BytesCon_MQTT[8] = 4; //protocoll level 0x04
        BytesCon_MQTT[9] = 0; //no user, no pw, no retain, no will qos or flag, no clean
        BytesCon_MQTT[10] = 0; //HighByte Keep Alive MSB 0=disabled
        BytesCon_MQTT[11] = 0; //Low Byte Keep Alive MSB 0=disabled'


            byte[] BytesDisCon_MQTT = new byte[2];
            BytesDisCon_MQTT[0] = bMessageHeaderDisconnect;
            BytesDisCon_MQTT[1] = 0;

            byte[] byInbound=new byte[1000];

            sock.Send(BytesCon_MQTT);
            Thread.Sleep(1);
            sock.Receive(byInbound);
            
            sock.Send(BytesData_MQTT);
            Thread.Sleep(1);
            sock.Receive(byInbound);
            sock.Send(BytesDisCon_MQTT);
            Thread.Sleep(1);
            sock.Receive(byInbound);
            Console.WriteLine(sock.Connected.ToString());

            sock.Disconnect(false);
            sock.Close();
            Console.WriteLine(sock.Connected.ToString());


            
            
        }
    }
}

标签： c#mqtt

c# - 在不使用堆栈的情况下创建精简 MQTT 发布者（操作方法）

问题描述

解决方案

推荐阅读