物联网协议Coap之C#基于Mozi的CoapServer实现解析

拼搏现实的明天。 2024-02-06 00:28 41阅读 0赞

##  ##

**目录**

前言

一、C\#的Coap Server实现

1、CoapServer相关类

2、主要类解析

3、资源控制器定义

4、ResourceManager管理器

二、CoapServer生命周期

1、Server创建代码

2、服务端创建

3、绑定endpoint

4、准备接收请求

总结

--------------------

## 前言 ##

在之前的关于物联网协议的介绍中，我们详细介绍了如何基于Java进行Coap协议的开发，由于一些项目原因，在项目中采用的不是Java的技术栈，而是ASP.NET Core,因此需要基于C\#进行Coap协议的开发与实现。Coap本身是与编程语言无关的，不仅可以用Java进行实现，当然也可以使用C\#，还可以是Python、GO等多语言，感兴趣的朋友可以自行问度娘，其实每一种语言都有相应的Coap实现。以下是[weixin\_34026276][weixin_34026276]博主分享的博客，大家可以自己熟悉的编程语言所进行的开源实现，[Coap各编程语言实现传送门][Coap]。非常感谢他的认真整理。

<table> 
 <tbody> 
  <tr> 
   <th>名称</th> 
   <th>开发语言</th> 
   <th>CoAP版本</th> 
   <th>客户端/服务端</th> 
   <th>实现的CoAP特征</th> 
   <th>开源协议</th> 
   <th>项目链接地址</th> 
  </tr> 
 </tbody> 
 <tbody> 
  <tr> 
   <td>Californium</td> 
   <td>Java</td> 
   <td><a href="https://tools.ietf.org/html/rfc7252" rel="nofollow" title="RFC 7252">RFC 7252</a></td> 
   <td>Client + Server</td> 
   <td>Observe, Blockwise Transfers, DTLS</td> 
   <td>EPL+EDL</td> 
   <td><a href="https://www.eclipse.org/californium" rel="nofollow" title="Eclipse Californium™">Eclipse Californium™</a></td> 
  </tr> 
  <tr> 
   <td>cantcoap</td> 
   <td>C++/C</td> 
   <td><a href="https://tools.ietf.org/html/rfc7252" rel="nofollow" title="RFC 7252">RFC 7252</a></td> 
   <td>Client + Server</td> 
   <td></td> 
   <td>BSD</td> 
   <td><a href="https://github.com/staropram/cantcoap" title="https://github.com/staropram/cantcoap" rel="nofollow">https://github.com/staropram/cantcoap</a></td> 
  </tr> 
  <tr> 
   <td>CoAP implementation for Go</td> 
   <td><a href="https://en.wikipedia.org/wiki/Go_%28programming_language%29" rel="nofollow" title="Go">Go</a></td> 
   <td><a href="https://tools.ietf.org/html/rfc7252" rel="nofollow" title="RFC 7252">RFC 7252</a></td> 
   <td>Client + Server</td> 
   <td>Core + Draft Subscribe</td> 
   <td>MIT</td> 
   <td><a href="https://github.com/dustin/go-coap" title="https://github.com/dustin/go-coap" rel="nofollow">https://github.com/dustin/go-coap</a></td> 
  </tr> 
  <tr> 
   <td>CoAP.NET</td> 
   <td>C#</td> 
   <td><a href="https://tools.ietf.org/html/rfc7252" rel="nofollow" title="RFC 7252">RFC 7252</a>, coap-13, coap-08, coap-03</td> 
   <td>Client + Server</td> 
   <td>Core, Observe, Blockwise Transfers</td> 
   <td>3-clause BSD</td> 
   <td><a href="https://github.com/smeshlink/CoAP.NET" title="https://github.com/smeshlink/CoAP.NET" rel="nofollow">https://github.com/smeshlink/CoAP.NET</a></td> 
  </tr> 
  <tr> 
   <td>CoAPSharp</td> 
   <td>C#, .NET</td> 
   <td><a href="https://tools.ietf.org/html/rfc7252" rel="nofollow" title="RFC 7252">RFC 7252</a></td> 
   <td>Client + Server</td> 
   <td>Core, Observe, Block, RD</td> 
   <td>LGPL</td> 
   <td><a href="http://www.coapsharp.com/" rel="nofollow" title="http://www.coapsharp.com">http://www.coapsharp.com</a></td> 
  </tr> 
  <tr> 
   <td>CoAPthon</td> 
   <td>Python</td> 
   <td><a href="https://tools.ietf.org/html/rfc7252" rel="nofollow" title="RFC 7252">RFC 7252</a></td> 
   <td>Client + Server + Forward Proxy + Reverse Proxy</td> 
   <td>Observe, Multicast server discovery, CoRE Link Format parsing, Block-wise</td> 
   <td>MIT</td> 
   <td><a href="https://github.com/Tanganelli/CoAPthon" title="https://github.com/Tanganelli/CoAPthon" rel="nofollow">https://github.com/Tanganelli/CoAPthon</a></td> 
  </tr> 
  <tr> 
   <td>Copper</td> 
   <td>JavaScript (Browser Plugin)</td> 
   <td><a href="https://tools.ietf.org/html/rfc7252" rel="nofollow" title="RFC 7252">RFC 7252</a></td> 
   <td>Client</td> 
   <td>Observe, Blockwise Transfers</td> 
   <td>3-clause BSD</td> 
   <td><a href="https://github.com/mkovatsc/Copper" title="https://github.com/mkovatsc/Copper" rel="nofollow">https://github.com/mkovatsc/Copper</a><a href="https://addons.mozilla.org/de/firefox/addon/copper-270430/" rel="nofollow" title="https://addons.mozilla.org/de/firefox/addon/copper-270430/">https://addons.mozilla.org/de/firefox/addon/copper-270430/</a></td> 
  </tr> 
  <tr> 
   <td>eCoAP</td> 
   <td>C</td> 
   <td><a href="https://tools.ietf.org/html/rfc7252" rel="nofollow" title="RFC 7252">RFC 7252</a></td> 
   <td>Client + Server</td> 
   <td>Core</td> 
   <td>MIT</td> 
   <td><a href="https://gitlab.com/jobol/ecoap" rel="nofollow" title="josé bollo / ecoap · GitLab">josé bollo / ecoap · GitLab</a></td> 
  </tr> 
  <tr> 
   <td>Erbium for Contiki</td> 
   <td>C</td> 
   <td><a href="https://tools.ietf.org/html/rfc7252" rel="nofollow" title="RFC 7252">RFC 7252</a></td> 
   <td>Client + Server</td> 
   <td>Observe, Blockwise Transfers</td> 
   <td>3-clause BSD</td> 
   <td><a href="http://www.contiki-os.org/" rel="nofollow" title="Contiki: The Open Source Operating System for the Internet      of Things">Contiki: The Open Source Operating System for the Internet of Things</a>&nbsp;(er-rest-example)</td> 
  </tr> 
  <tr> 
   <td>ETRI CoAP</td> 
   <td>C</td> 
   <td><a href="https://tools.ietf.org/html/rfc7252" rel="nofollow" title="RFC 7252">RFC 7252</a></td> 
   <td>Client + Server</td> 
   <td>Core, Observe, Block</td> 
   <td>Commercial</td> 
   <td><a href="http://coap.or.kr/index_en.html" rel="nofollow" title="http://coap.or.kr/index_en.html">http://coap.or.kr/index_en.html</a></td> 
  </tr> 
  <tr> 
   <td>iCoAP</td> 
   <td>Objective-C</td> 
   <td><a href="https://tools.ietf.org/html/rfc7252" rel="nofollow" title="RFC 7252">RFC 7252</a></td> 
   <td>Client</td> 
   <td>Core, Observe, Blockwise Transfers</td> 
   <td>MIT</td> 
   <td><a href="https://github.com/stuffrabbit/iCoAP" title="https://github.com/stuffrabbit/iCoAP" rel="nofollow">https://github.com/stuffrabbit/iCoAP</a></td> 
  </tr> 
  <tr> 
   <td>jCoAP</td> 
   <td>Java</td> 
   <td><a href="https://tools.ietf.org/html/rfc7252" rel="nofollow" title="RFC 7252">RFC 7252</a></td> 
   <td>Client + Server</td> 
   <td>Observe, Blockwise Transfers</td> 
   <td>Apache License 2.0</td> 
   <td><a href="https://code.google.com/p/jcoap/" rel="nofollow" title="https://code.google.com/p/jcoap/">https://code.google.com/p/jcoap/</a></td> 
  </tr> 
  <tr> 
   <td>libcoap</td> 
   <td>C</td> 
   <td><a href="https://tools.ietf.org/html/rfc7252" rel="nofollow" title="RFC 7252">RFC 7252</a></td> 
   <td>Client + Server</td> 
   <td>Observe, Blockwise Transfers</td> 
   <td>BSD/GPL</td> 
   <td><a href="http://sourceforge.net/projects/libcoap/develop" rel="nofollow" title="libcoap: C-Implementation of CoAP download | SourceForge.net">libcoap: C-Implementation of CoAP download | SourceForge.net</a></td> 
  </tr> 
  <tr> 
   <td>microcoap</td> 
   <td>C</td> 
   <td><a href="https://tools.ietf.org/html/rfc7252" rel="nofollow" title="RFC 7252">RFC 7252</a></td> 
   <td>Client + Server</td> 
   <td></td> 
   <td>MIT</td> 
   <td><a href="https://github.com/1248/microcoap" title="https://github.com/1248/microcoap" rel="nofollow">https://github.com/1248/microcoap</a></td> 
  </tr> 
  <tr> 
   <td>nCoap</td> 
   <td>Java</td> 
   <td><a href="https://tools.ietf.org/html/rfc7252" rel="nofollow" title="RFC 7252">RFC 7252</a></td> 
   <td>Client + Server</td> 
   <td>Observe</td> 
   <td>BSD</td> 
   <td><a href="https://github.com/okleine/nCoAP" title="https://github.com/okleine/nCoAP" rel="nofollow">https://github.com/okleine/nCoAP</a></td> 
  </tr> 
  <tr> 
   <td>node-coap</td> 
   <td>Javascript</td> 
   <td><a href="https://tools.ietf.org/html/rfc7252" rel="nofollow" title="RFC 7252">RFC 7252</a></td> 
   <td>Client + Server</td> 
   <td>Core, Observe, Block</td> 
   <td>MIT</td> 
   <td><a href="https://github.com/mcollina/node-coap" title="https://github.com/mcollina/node-coap" rel="nofollow">https://github.com/mcollina/node-coap</a></td> 
  </tr> 
  <tr> 
   <td>Ruby coap</td> 
   <td>Ruby</td> 
   <td><a href="https://tools.ietf.org/html/rfc7252" rel="nofollow" title="RFC 7252">RFC 7252</a></td> 
   <td>Client + Server (david)</td> 
   <td>Core, Observe, Block, RD</td> 
   <td>MIT, GPL</td> 
   <td><a href="https://github.com/nning/coap" title="https://github.com/nning/coap" rel="nofollow">https://github.com/nning/coap</a><br><a href="https://github.com/nning/david" title="https://github.com/nning/david" rel="nofollow">https://github.com/nning/david</a></td> 
  </tr> 
  <tr> 
   <td>Sensinode C Device Library</td> 
   <td>C</td> 
   <td><a href="https://tools.ietf.org/html/rfc7252" rel="nofollow" title="RFC 7252">RFC 7252</a></td> 
   <td>Client + Server</td> 
   <td>Core, Observe, Block, RD</td> 
   <td>Commercial</td> 
   <td><a href="https://silver.arm.com/browse/SEN00" rel="nofollow" title="Downloads - Arm Developer">Downloads - Arm Developer</a></td> 
  </tr> 
  <tr> 
   <td>Sensinode Java Device Library</td> 
   <td>Java SE</td> 
   <td><a href="https://tools.ietf.org/html/rfc7252" rel="nofollow" title="RFC 7252">RFC 7252</a></td> 
   <td>Client + Server</td> 
   <td>Core, Observe, Block, RD</td> 
   <td>Commercial</td> 
   <td><a href="https://silver.arm.com/browse/SEN00" rel="nofollow" title="Downloads - Arm Developer">Downloads - Arm Developer</a></td> 
  </tr> 
  <tr> 
   <td>Sensinode NanoService Platform</td> 
   <td>Java SE</td> 
   <td><a href="https://tools.ietf.org/html/rfc7252" rel="nofollow" title="RFC 7252">RFC 7252</a></td> 
   <td>Cloud Server</td> 
   <td>Core, Observe, Block, RD</td> 
   <td>Commercial</td> 
   <td><a href="https://silver.arm.com/browse/SEN00" rel="nofollow" title="Downloads - Arm Developer">Downloads - Arm Developer</a></td> 
  </tr> 
  <tr> 
   <td>SMCP</td> 
   <td>C</td> 
   <td><a href="https://tools.ietf.org/html/rfc7252" rel="nofollow" title="RFC 7252">RFC 7252</a></td> 
   <td>Client + Server</td> 
   <td>Core, Observe, Block</td> 
   <td>MIT</td> 
   <td><a href="https://github.com/darconeous/smcp" title="https://github.com/darconeous/smcp" rel="nofollow">https://github.com/darconeous/smcp</a></td> 
  </tr> 
  <tr> 
   <td>SwiftCoAP</td> 
   <td>Swift</td> 
   <td><a href="https://tools.ietf.org/html/rfc7252" rel="nofollow" title="RFC 7252">RFC 7252</a></td> 
   <td>Client + Server</td> 
   <td>Core, Observe, Blockwise Transfers</td> 
   <td>MIT</td> 
   <td><a href="https://github.com/stuffrabbit/SwiftCoAP" title="https://github.com/stuffrabbit/SwiftCoAP" rel="nofollow">https://github.com/stuffrabbit/SwiftCoAP</a></td> 
  </tr> 
  <tr> 
   <td>TinyOS CoapBlip</td> 
   <td>nesC/C</td> 
   <td>coap-13</td> 
   <td>Client + Server</td> 
   <td>Observe, Blockwise Transfers</td> 
   <td>BSD</td> 
   <td><a href="http://docs.tinyos.net/tinywiki/index.php/CoAP" rel="nofollow" title="http://docs.tinyos.net/tinywiki/index.php/CoAP">http://docs.tinyos.net/tinywiki/index.php/CoAP</a></td> 
  </tr> 
  <tr> 
   <td>txThings</td> 
   <td>Python (Twisted)</td> 
   <td><a href="https://tools.ietf.org/html/rfc7252" rel="nofollow" title="RFC 7252">RFC 7252</a></td> 
   <td>Client + Server</td> 
   <td>Blockwise Transfers, Observe (partial)</td> 
   <td>MIT</td> 
   <td><a href="https://github.com/siskin/txThings/" title="https://github.com/siskin/txThings/" rel="nofollow">https://github.com/siskin/txThings/</a></td> 
  </tr> 
 </tbody> 
</table>

由于对ASP.NET Core并不是很熟悉，在进行基础入门编程学习之后后，我们基于Mozi开源框架进行扩展扩展实现，[这是gitee上mozi项目地址][gitee_mozi]。原本的项目包含的内容比较多，我们可以在它的基础之上进行简化，改造成符合自己需求的项目。本文以CoapServer为主线，介绍CoapServer使用C\#语言的定义以及后台资源管理类的定义和实现。

## 一、C\#的Coap Server实现 ##

本节将重点介绍CoapServer在C\#中的设计与实现，由于Coap协议在Java的篇章中有所涉及，相信大家对Coap已经不再陌生，因此这里不再对Coap进行赘述。下面依然采用熟悉的OOA即面向对象分析，采用面向对象的方式进行源代码分析。

### 1、CoapServer相关类 ###

![c5ef607d1eab4e3ba5b6893aeae259f7.png][]

在CoapServer中，在这个工程中，主要涉及的类如下：

<table> 
 <tbody> 
  <tr> 
   <td style="width:104px;">序号</td> 
   <td style="width:226px;">类名</td> 
   <td style="width:352px;">说明</td> 
  </tr> 
  <tr> 
   <td style="width:104px;">1</td> 
   <td style="width:226px;">CoAPServer</td> 
   <td style="width:352px;">CoAP的服务端</td> 
  </tr> 
  <tr> 
   <td style="width:104px;">2</td> 
   <td style="width:226px;">CoAPResource</td> 
   <td style="width:352px;">类似于Java的中controller</td> 
  </tr> 
  <tr> 
   <td style="width:104px;">3</td> 
   <td style="width:226px;">ResourceManager</td> 
   <td style="width:352px;">资源管理器，可以理解成IOC容器</td> 
  </tr> 
 </tbody> 
</table>

### 2、主要类解析 ###

CoapServer是服务端程序中最重要的类，其中主要定义了后端的服务，以及绑定了Coap协议，用于接收前端来自Client的请求。

![510148038bd9405eb3102754e6f5a30a.png][]

从类的继承体系来说，CoapServer是CoAPPeer的子类，有必要对CoAPPeer进行一个全面的说明。

![68786631d10349bb9d1be324a5e854d7.png][]

using System;
    using System.Collections.Generic;
    namespace Mozi.IoT
    {
        /// <summary>
        /// CoAP对等端
        /// </summary>
        public class CoAPPeer
        {
            /// <summary>
            /// 最大数据包尺寸 包含所有头信息和有效荷载 Byte
            /// </summary>
            private int _maxTransferPackSize = 512;
            private int _blockSize = 128;
            private ulong _packetSendCount, _totalSendBytes, _packetReceived = 0, _totalReceivedBytes;
            protected UDPSocketIOCP _socket;
            protected int BindPort = CoAPProtocol.Port;
            /// <summary>
            /// 最小分块大小,单位Byte
            /// </summary>
            public const int MinBlockSize = 16;
            /// <summary>
            /// 最大分块大小,单位Byte
            /// </summary>
            public const int MaxBlockSize = 2048;
            /// <summary>
            /// 当前端默认采用块大小,默认值为128bytes,单位Byte
            /// </summary>
            /// <remarks>在通讯两方没有进行协商的情况下，默认采用此值作为分块大小。取值区间为{<see cref="MinBlockSize"/>~<see cref="MaxBlockSize"/>}</remarks>
            public int BlockSize { get { return _blockSize; } set { _blockSize = value; } }
            /// <summary>s
            /// 受支持的请求方法
            /// </summary>
            protected List<CoAPCode> SupportedRequest = new List<CoAPCode> { CoAPRequestMethod.Get, CoAPRequestMethod.Post, CoAPRequestMethod.Put, CoAPRequestMethod.Delete };
            /// <summary>
            /// 数据包接收事件，字节流数据包
            /// </summary>
            public PackageReceive DatagramReceived;
            /// <summary>
            /// 服务端口
            /// </summary>
            public int Port { get { return BindPort; } protected set { BindPort = value; } }
            /// <summary>
            /// 启动时间
            /// </summary>
            public DateTime StartTime { get; private set; }
            /// <summary>
            /// 服务器运行状态
            /// </summary>
            public bool Running
            {
                get; set;
            }
            /// <summary>
            /// 最大数据包尺寸 包含所有头信息和有效荷载
            /// </summary>
            internal int MaxTransferPackSize { get => _maxTransferPackSize; set => _maxTransferPackSize = value; }
            /// <summary>
            /// 累计接收到的包的数量
            /// </summary>
            public ulong PacketReceivedCount { get => _packetReceived; }
            /// <summary>
            /// 累计接收的字节数
            /// </summary>
            public ulong TotalReceivedBytes { get => _totalReceivedBytes; }
            /// <summary>
            /// 累计发出的包的数量
            /// </summary>
            public ulong PacketSendCount => _packetSendCount;
            /// <summary>                                                               
            /// 累计发出的字节数                                                                
            /// </summary>
            public ulong TotalSendBytes => _totalSendBytes; 
    
            public CoAPPeer()
            {
                _socket = new UDPSocketIOCP();
                _socket.AfterReceiveEnd += Socket_AfterReceiveEnd;
            }
            /// <summary>
            /// 以指定端口启动<see cref="F:Port"/>，如果不配置端口则使用默认端口
            /// </summary>
            public void Start()
            {
                Start(BindPort);
            }
            /// <summary>
            /// 启动本端服务 默认5683端口
            /// </summary>
            /// <param name="port"></param>
            public void Start(int port)
            {
                BindPort = port;
                _socket.Start(BindPort);
                StartTime = DateTime.Now;
                Running = true;
            }
            /// <summary>
            /// 端口下线
            /// </summary>
            public void Shutdown()
            {
                _socket.Shutdown();
                StartTime = DateTime.MinValue;
                Running = false;
            }
            /// <summary>
            /// 数据接收完成回调
            /// </summary>
            /// <param name="sender"></param>
            /// <param name="args"></param>
            /// <remarks>继承类如果覆盖该事件，则可以接管数据处理</remarks>
            protected virtual void Socket_AfterReceiveEnd(object sender, DataTransferArgs args)
            {
                _packetReceived++;
                _totalReceivedBytes += args.Data != null ? (uint)args.Data.Length : 0;
                if (DatagramReceived != null)
                {
                    DatagramReceived(args.IP, args.Port, args.Data);
                }
            }
        }
    }

从以上的代码中可以发现，上述类也是定义了CoAP协议工作所必须要的一些属性，比如端口、协议、数据包内容等等。CoapServer的属性代码如下：

private Cache.MessageCacheManager _cm;
    
    /// <summary>
    /// 接收到请求
    /// </summary>
    public MessageTransmit RequestReceived;
    /// <summary>
    /// 发起响应请求
    /// </summary>
    public MessageTransmit Responsed;
    private bool _proxyPassed = false;
    private uint maxBodySize=20*1024*1024;
    /// <summary>
    /// 服务端能处理的最大POST资源大小 单位byte
    /// </summary>
    public uint MaxBodySize { get => maxBodySize; set => maxBodySize = value; }
    /// <summary>
    /// 服务器根目录
    /// </summary>
    public string Root = AppDomain.CurrentDomain.BaseDirectory;

### 3、资源控制器定义 ###

每一个后台都会对应一个资源控制器，这里也不例外，我们来看下C\#的实现。在CoapResource中同样的定义了get、post、put、delete四种请求方法。如下图所示：

![52e48c0b8dfa435098a2ece9721e91e6.png][]

/// <summary>
        /// CoAP资源
        /// </summary>
        public abstract class CoAPResource
        {
            /// <summary>
            /// 资源总大小
            /// </summary>
            public abstract uint ResourceSize { get; }
            /// <summary>
            /// 默认分块大小128，单位Bytes 
            /// </summary>
            /// <remarks>
            /// 如果资源尺寸过大，则必须合理配置此大小。
            /// 取值范围为16-2048Bytes BlockOptionValue中Size的数据容量。参考<see cref="BlockOptionValue"/>
            /// </remarks>
            public virtual uint BlockSize { get { return 128; } }
            /// <summary>
            /// GET方法
            /// </summary>
            /// <param name="ctx"></param>
            /// <returns></returns>
            public virtual CoAPPackage OnGet(CoAPContext ctx)
            {
                ctx.Response = new CoAPPackage { MessageType = CoAPMessageType.Acknowledgement, MesssageId = ctx.Request.MesssageId, Token = ctx.Request.Token, Code = CoAPResponseCode.Forbidden };
                return ctx.Response;
            }
            /// <summary>
            /// Post方法
            /// </summary>
            /// <param name="ctx"></param>
            /// <returns></returns>
            public virtual CoAPPackage OnPost(CoAPContext ctx)
            {
                ctx.Response = new CoAPPackage { MessageType = CoAPMessageType.Acknowledgement, MesssageId = ctx.Request.MesssageId, Token = ctx.Request.Token, Code = CoAPResponseCode.Forbidden };
                return ctx.Response;
            }
            /// <summary>
            /// PUT方法
            /// </summary>
            /// <param name="ctx"></param>
            /// <returns></returns>
            public virtual CoAPPackage OnPut(CoAPContext ctx)
            {
                ctx.Response = new CoAPPackage { MessageType = CoAPMessageType.Acknowledgement, MesssageId = ctx.Request.MesssageId, Token = ctx.Request.Token, Code = CoAPResponseCode.Forbidden };
                return ctx.Response;
            }
            /// <summary>
            /// Delete方法
            /// </summary>
            /// <param name="ctx"></param>
            /// <returns></returns>
            public virtual CoAPPackage OnDelete(CoAPContext ctx)
            {
                ctx.Response = new CoAPPackage { MessageType = CoAPMessageType.Acknowledgement, MesssageId = ctx.Request.MesssageId, Token = ctx.Request.Token, Code = CoAPResponseCode.Forbidden };
                return ctx.Response;
            }
            /// <summary>
            /// 分块查找
            /// </summary>
            /// <param name="indBlock"></param>
            /// <param name="blockSize"></param>
            /// <returns></returns>
            protected virtual byte[] Seek(int indBlock, int blockSize)
            {
                return new byte[] { };
            }
            /// <summary>
            /// Block2分块协商
            /// </summary>
            /// <param name="ctx"></param>
            /// <returns></returns>
            internal virtual void HandleBlock2Query(CoAPContext ctx)
            {
                CoAPOption opt = ctx.Request.Options.Find(x => x.Option == CoAPOptionDefine.Block2);
                if (opt != null)
                {
                    OptionValue opt2 = new BlockOptionValue() { Pack = opt.Value.Pack };
                    //if(opt2)
                }
            }
            /// <summary>
            /// 请求服务端资源大小，响应条件为 Get Size2=0
            /// </summary>
            /// <param name="ctx">响应上下文对象</param>
            /// <returns></returns>
            internal virtual bool HandleSize2Query(CoAPContext ctx)
            {
                CoAPOption opt = ctx.Request.Options.Find(x => x.Option == CoAPOptionDefine.Size2);
                if (opt != null && int.Parse(opt.Value.ToString()) ==0 && ctx.Request.Code == CoAPRequestMethod.Get)
                {
    
                    ctx.Response = new CoAPPackage { MessageType = CoAPMessageType.Acknowledgement, MesssageId = ctx.Request.MesssageId, Token = ctx.Request.Token, Code = CoAPResponseCode.Content };
    
                    CoAPOption optResp = new CoAPOption() { Option = CoAPOptionDefine.Size2, Value = new UnsignedIntegerOptionValue() { Value = ResourceSize } };
                    
                    ctx.Response.SetOption(optResp);
                    return true;
                }
                else
                {
                    return false;
                }
            }
        }

### 4、ResourceManager管理器 ###

每个业务接收类都对应一个Resource，而这些Resource必须要使用一个统一的容器管理起来，可以把它理解成Java对应的IOC容器，程序运行时会自动把相关资源管理起来。资源描述如下

public class ResourceDescriptionAttribute : Attribute
        {
            /// <summary>
            /// 命名空间
            /// </summary>
            public string Namespace { get; set; }
            /// <summary>
            /// 资源名称
            /// </summary>
            public string Name { get; set; }
            /// <summary>
            /// 文字描述
            /// </summary>
            public string Description { get; set; }
            /// <summary>
            /// 资源类型
            /// </summary>
            public string ResourceType { get; set; }
        }

资源管理器的核心管理方式也是采用反射的机制，如下：

![f3e551b4685945f9b77bf8e4a104dab3.png][]

## 二、CoapServer生命周期 ##

在上面的代码中，对CoapServer的编码实现进行了介绍，下面将采用熟悉的调试方法来进行调用跟踪，在关键代码中进行深度讲解。

### 1、Server创建代码 ###

创建Server的代码如下：

static void Main(string[] args)
            {
                Console.WriteLine("你好!COAP服务端已开启，等待客户端连接......");
                //服务端
                CoAPServer cs = new CoAPServer();
                cs.RequestReceived += new MessageTransmit((host, port, pack) =>
                {
                    Console.WriteLine($"From:[{host}:{port}]");
                    Console.WriteLine(pack.ToString());
                    Console.Title = string.Format("elapsed:{2},count:{0},pps:{3},bytes:{1}", cs.PacketReceivedCount, cs.TotalReceivedBytes,FormatSeconds(sp.ElapsedMilliseconds),pps);
                });
                cs.Start();
                Console.ReadLine();
            }

### 2、服务端创建 ###

第一步、调用构造方法

![ac1a5bb77d3c4bb3b1c3e8af79182e2b.png][]

第二步、指定端口启动

![87888d445399483693196be093325be0.png][]

第三步、设置socket，绑定协议

![88b4fb63436041119a4a222e683ad211.png][]

### 3、绑定endpoint ###

![1e5e41f7fe704aada00d5b5ff6b98933.png][]

### 4、准备接收请求 ###

![6bc0f687d08a46639448475ad150183c.png][]

## 总结 ##

以上就是本文的主要内容，本文以CoapServer为主线，介绍CoapServer使用C\#语言的定义以及后台资源管理类的定义和实现。行文仓促，定有不当之处，欢迎各位朋友专家批评指正。

[weixin_34026276]: https://blog.csdn.net/weixin_34026276
[Coap]: https://blog.csdn.net/weixin_34026276/article/details/91932616
[gitee_mozi]: https://gitee.com/illblood/mozi/
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[ac1a5bb77d3c4bb3b1c3e8af79182e2b.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/30/ee6ad011720f4c1e9f8caafee2a65e2f.png
[87888d445399483693196be093325be0.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/30/307d941d05984f6e86b2fffead70ba2c.png
[88b4fb63436041119a4a222e683ad211.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/30/6e190050376c4e2099254cd2a4c5895f.png
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