Asp.NetCore輕松學-實現一個輕量級高可復用的RabbitMQ客戶端

目錄

• 前言
• 1. 創建基礎連接管理幫助類
• 2. 定義和實現服務契約
• 3. 開始使用
• 4. 測試代碼
• 結語

 

前言

本示例通過對服務訂閱的封裝、隱藏細節實現、統一配置、自動重連、異常處理等各個方面來打造一個簡單易用的 RabbitMQ 工廠；本文適合適合有一定 RabbitMQ 使用經驗的讀者閱讀，如果你還沒有實際使用過 RabbitMQ，也沒有關系，因為本文的代碼都是基於直接運行的實例，通過簡單的修改 RabbitMQ 即可運行。

• 解決方案如下

1. 創建基礎連接管理幫助類

首先，創建一個 .netcore 控制台項目，創建 Helper、Service、Utils 文件夾，分別用於存放通道管理、服務訂閱、公共組件。

1.1 接下來創建一個 MQConfig 類，用於存放 RabbitMQ 主機配置等信息

    public class MQConfig
    {
        /// <summary>
        /// 訪問消息隊列的用戶名
        /// </summary>
        public string UserName { get; set; }
        /// <summary>
        /// 訪問消息隊列的密碼
        /// </summary>
        public string Password { get; set; }
        /// <summary>
        /// 消息隊列的主機地址
        /// </summary>
        public string HostName { get; set; }
        /// <summary>
        /// 消息隊列的主機開放的端口
        /// </summary>
        public int Port { get; set; }
    }

1.2 創建 RabbitMQ 連接管理類，用於創建連接，關閉連接

1.3 創建一個消息體對象 MessageBody，用於解析和傳遞消息到業務系統中，在接下來的 MQChannel 類中會用到

  public class MessageBody
    {
        public EventingBasicConsumer Consumer { get; set; }
        public BasicDeliverEventArgs BasicDeliver { get; set; }
        /// <summary>
        /// 0成功
        /// </summary>
        public int Code { get; set; }
        public string Content { get; set; }
        public string ErrorMessage { get; set; }
        public bool Error { get; set; }
        public Exception Exception { get; set; }
    }

1.4 創建一個通道類，用於訂閱、發布消息，同時提供一個關閉通道連接的方法 Stop

 public class MQChannel
    {
        public string ExchangeTypeName { get; set; }
        public string ExchangeName { get; set; }
        public string QueueName { get; set; }
        public string RoutekeyName { get; set; }
        public IConnection Connection { get; set; }
        public EventingBasicConsumer Consumer { get; set; }
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;summary&gt;</span></span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span>  外部訂閱消費者通知委托</span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;/summary&gt;</span></span>
    <span class="hljs-keyword">public</span> Action&lt;MessageBody&gt; OnReceivedCallback { <span class="hljs-keyword">get</span>; <span class="hljs-keyword">set</span>; }

    <span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-title">MQChannel</span>(<span class="hljs-params"><span class="hljs-keyword">string</span> exchangeType, <span class="hljs-keyword">string</span> exchange, <span class="hljs-keyword">string</span> queue, <span class="hljs-keyword">string</span> routekey</span>)
    </span>{
        <span class="hljs-keyword">this</span>.ExchangeTypeName = exchangeType;
        <span class="hljs-keyword">this</span>.ExchangeName = exchange;
        <span class="hljs-keyword">this</span>.QueueName = queue;
        <span class="hljs-keyword">this</span>.RoutekeyName = routekey;
    }

    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;summary&gt;</span></span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span>  向當前隊列發送消息</span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;/summary&gt;</span></span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;param name="content"&gt;</span><span class="hljs-doctag">&lt;/param&gt;</span></span>
    <span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">Publish</span>(<span class="hljs-params"><span class="hljs-keyword">string</span> content</span>)
    </span>{
        <span class="hljs-keyword">byte</span>[] body = MQConnection.UTF8.GetBytes(content);
        IBasicProperties prop = <span class="hljs-keyword">new</span> BasicProperties();
        prop.DeliveryMode = <span class="hljs-number">1</span>;
        Consumer.Model.BasicPublish(<span class="hljs-keyword">this</span>.ExchangeName, <span class="hljs-keyword">this</span>.RoutekeyName, <span class="hljs-literal">false</span>, prop, body);
    }

    <span class="hljs-function"><span class="hljs-keyword">internal</span> <span class="hljs-keyword">void</span> <span class="hljs-title">Receive</span>(<span class="hljs-params"><span class="hljs-keyword">object</span> sender, BasicDeliverEventArgs e</span>)
    </span>{
        MessageBody body = <span class="hljs-keyword">new</span> MessageBody();
        <span class="hljs-keyword">try</span>
        {
            <span class="hljs-keyword">string</span> content = MQConnection.UTF8.GetString(e.Body);
            body.Content = content;
            body.Consumer = (EventingBasicConsumer)sender;
            body.BasicDeliver = e;
        }
        <span class="hljs-keyword">catch</span> (Exception ex)
        {
            body.ErrorMessage = <span class="hljs-string">$"訂閱-出錯<span class="hljs-subst">{ex.Message}</span>"</span>;
            body.Exception = ex;
            body.Error = <span class="hljs-literal">true</span>;
            body.Code = <span class="hljs-number">500</span>;
        }
        OnReceivedCallback?.Invoke(body);
    }

    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;summary&gt;</span></span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span>  設置消息處理完成標志</span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;/summary&gt;</span></span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;param name="consumer"&gt;</span><span class="hljs-doctag">&lt;/param&gt;</span></span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;param name="deliveryTag"&gt;</span><span class="hljs-doctag">&lt;/param&gt;</span></span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;param name="multiple"&gt;</span><span class="hljs-doctag">&lt;/param&gt;</span></span>
    <span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">SetBasicAck</span>(<span class="hljs-params">EventingBasicConsumer consumer, <span class="hljs-keyword">ulong</span> deliveryTag, <span class="hljs-keyword">bool</span> multiple</span>)
    </span>{
        consumer.Model.BasicAck(deliveryTag, multiple);
    }

    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;summary&gt;</span></span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span>  關閉消息隊列的連接</span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;/summary&gt;</span></span>
    <span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">Stop</span>(<span class="hljs-params"></span>)
    </span>{
        <span class="hljs-keyword">if</span> (<span class="hljs-keyword">this</span>.Connection != <span class="hljs-literal">null</span> &amp;&amp; <span class="hljs-keyword">this</span>.Connection.IsOpen)
        {
            <span class="hljs-keyword">this</span>.Connection.Close();
            <span class="hljs-keyword">this</span>.Connection.Dispose();
        }
    }
}</code></pre>

1.5 在上面的 MQChannel 類中


       
       
       
               
 
                
首先是在構造函數內對當前通道的屬性進行設置，其次提供了 Publish 和 OnReceivedCallback 的委托，當通道接收到消息的時候，會進入方法 Receive 中，在 Receive 中，經過封裝成 MessageBody 對象，並調用委托 OnReceivedCallback ，將，解析好的消息傳遞到外邊訂閱者的業務中。最終在 MQChannel 中還提供了消息確認的操作方法 SetBasicAck，供業務系統手動調用。
 
               
1.6 接着再創建一個 RabbitMQ 通道管理類，用於創建通道，代碼非常簡單，只有一個公共方法 CreateReceiveChannel，傳入相關參數，創建一個 MQChannel 對象
    public class MQChannelManager
    {
        public MQConnection MQConn { get; set; }
    <span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-title">MQChannelManager</span>(<span class="hljs-params">MQConnection conn</span>)
    </span>{
        <span class="hljs-keyword">this</span>.MQConn = conn;
    }

    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;summary&gt;</span></span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span>  創建消息通道</span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;/summary&gt;</span></span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;param name="cfg"&gt;</span><span class="hljs-doctag">&lt;/param&gt;</span></span>
    <span class="hljs-function"><span class="hljs-keyword">public</span> MQChannel <span class="hljs-title">CreateReceiveChannel</span>(<span class="hljs-params"><span class="hljs-keyword">string</span> exchangeType, <span class="hljs-keyword">string</span> exchange, <span class="hljs-keyword">string</span> queue, <span class="hljs-keyword">string</span> routekey</span>)
    </span>{
        IModel model = <span class="hljs-keyword">this</span>.CreateModel(exchangeType, exchange, queue, routekey);
        model.BasicQos(<span class="hljs-number">0</span>, <span class="hljs-number">1</span>, <span class="hljs-literal">false</span>);
        EventingBasicConsumer consumer = <span class="hljs-keyword">this</span>.CreateConsumer(model, queue);
        MQChannel channel = <span class="hljs-keyword">new</span> MQChannel(exchangeType, exchange, queue, routekey)
        {
            Connection = <span class="hljs-keyword">this</span>.MQConn.Connection,
            Consumer = consumer
        };
        consumer.Received += channel.Receive;
        <span class="hljs-keyword">return</span> channel;
    }

    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;summary&gt;</span></span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span>  創建一個通道，包含交換機/隊列/路由，並建立綁定關系</span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;/summary&gt;</span></span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;param name="type"&gt;</span>交換機類型<span class="hljs-doctag">&lt;/param&gt;</span></span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;param name="exchange"&gt;</span>交換機名稱<span class="hljs-doctag">&lt;/param&gt;</span></span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;param name="queue"&gt;</span>隊列名稱<span class="hljs-doctag">&lt;/param&gt;</span></span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;param name="routeKey"&gt;</span>路由名稱<span class="hljs-doctag">&lt;/param&gt;</span></span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;returns&gt;</span><span class="hljs-doctag">&lt;/returns&gt;</span></span>
    <span class="hljs-function"><span class="hljs-keyword">private</span> IModel <span class="hljs-title">CreateModel</span>(<span class="hljs-params"><span class="hljs-keyword">string</span> type, <span class="hljs-keyword">string</span> exchange, <span class="hljs-keyword">string</span> queue, <span class="hljs-keyword">string</span> routeKey, IDictionary&lt;<span class="hljs-keyword">string</span>, <span class="hljs-keyword">object</span>&gt; arguments = <span class="hljs-literal">null</span></span>)
    </span>{
        type = <span class="hljs-keyword">string</span>.IsNullOrEmpty(type) ? <span class="hljs-string">"default"</span> : type;
        IModel model = <span class="hljs-keyword">this</span>.MQConn.Connection.CreateModel();
        model.BasicQos(<span class="hljs-number">0</span>, <span class="hljs-number">1</span>, <span class="hljs-literal">false</span>);
        model.QueueDeclare(queue, <span class="hljs-literal">true</span>, <span class="hljs-literal">false</span>, <span class="hljs-literal">false</span>, arguments);
        model.QueueBind(queue, exchange, routeKey);
        <span class="hljs-keyword">return</span> model;
    }

    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;summary&gt;</span></span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span>  接收消息到隊列中</span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;/summary&gt;</span></span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;param name="model"&gt;</span>消息通道<span class="hljs-doctag">&lt;/param&gt;</span></span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;param name="queue"&gt;</span>隊列名稱<span class="hljs-doctag">&lt;/param&gt;</span></span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;param name="callback"&gt;</span>訂閱消息的回調事件<span class="hljs-doctag">&lt;/param&gt;</span></span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;returns&gt;</span><span class="hljs-doctag">&lt;/returns&gt;</span></span>
    <span class="hljs-function"><span class="hljs-keyword">private</span> EventingBasicConsumer <span class="hljs-title">CreateConsumer</span>(<span class="hljs-params">IModel model, <span class="hljs-keyword">string</span> queue</span>)
    </span>{
        EventingBasicConsumer consumer = <span class="hljs-keyword">new</span> EventingBasicConsumer(model);
        model.BasicConsume(queue, <span class="hljs-literal">false</span>, consumer);

        <span class="hljs-keyword">return</span> consumer;
    }
}</code></pre>

1.7 通道管理類的構造方法

 public MQChannelManager(MQConnection conn) {
            this.MQConn = conn;
        }
1.8 需要傳入一個 MQConnection 對象，僅是一個簡單的連接類，代碼如下

    public class MQConnection
    {
        private string vhost = string.Empty;
        private IConnection connection = null;
        private MQConfig config = null;

        /// <summary>
        /// 構造無 utf8 標記的編碼轉換器
        /// </summary>
        public static UTF8Encoding UTF8 { get; set; } = new UTF8Encoding(false);

        public MQConnection(MQConfig config, string vhost) {
            this.config = config;
            this.vhost = vhost;
        }

        public IConnection Connection
        {
            get
            {
                if (connection == null)
                {
                    ConnectionFactory factory = new ConnectionFactory
                    {
                        AutomaticRecoveryEnabled = true,
                        UserName = this.config.UserName,
                        Password = this.config.Password,
                        HostName = this.config.HostName,
                        VirtualHost = this.vhost,
                        Port = this.config.Port
                    };
                    connection = factory.CreateConnection();
                }

                return connection;
            }
        }
    }
1.9 在上面的代碼中，還初始化了一個靜態對象 UTF8Encoding ，使用無 utf8 標記的編碼轉換器來解析消息

2. 定義和實現服務契約

         
         
         
                 
 
                  
設想一下，有這樣的一個業務場景，通道管理和服務管理都是相同的操作，如果這些基礎操作都在一個地方定義，且有一個默認的實現，那么后來者就不需要去關注這些技術細節，直接繼承基礎類后，傳入相應的消息配置即可完成
 消息訂閱和發布操作。
 
                 
2.1 有了想法，接下來就先定義契約接口 IService，此接口包含創建通道、開啟/停止訂閱，一個服務可能承載多個通道，所以還需要包含通道列表
public interface IService
    {
        /// <summary>
        /// 創建通道
        /// </summary>
        /// <param name="queue">隊列名稱</param>
        /// <param name="routeKey">路由名稱</param>
        /// <param name="exchangeType">交換機類型</param>
        /// <returns></returns>
        MQChannel CreateChannel(string queue, string routeKey, string exchangeType);
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;summary&gt;</span></span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span>  開啟訂閱</span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;/summary&gt;</span></span>
    <span class="hljs-function"><span class="hljs-keyword">void</span> <span class="hljs-title">Start</span>(<span class="hljs-params"></span>)</span>;

    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;summary&gt;</span></span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span>  停止訂閱</span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;/summary&gt;</span></span>
    <span class="hljs-function"><span class="hljs-keyword">void</span> <span class="hljs-title">Stop</span>(<span class="hljs-params"></span>)</span>;

    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;summary&gt;</span></span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span>  通道列表</span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;/summary&gt;</span></span>
    List&lt;MQChannel&gt; Channels { <span class="hljs-keyword">get</span>; <span class="hljs-keyword">set</span>; }

    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;summary&gt;</span></span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span>  消息隊列中定義的虛擬機</span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;/summary&gt;</span></span>
    <span class="hljs-keyword">string</span> vHost { <span class="hljs-keyword">get</span>; }

    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;summary&gt;</span></span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span>  消息隊列中定義的交換機</span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;/summary&gt;</span></span>
    <span class="hljs-keyword">string</span> Exchange { <span class="hljs-keyword">get</span>; }
}</code></pre>

2.2 接下來創建一個抽象類來實現該接口，將實現細節進行封裝，方便后面的業務服務繼承調用

  public abstract class MQServiceBase : IService
    {
        internal bool started = false;
        internal MQServiceBase(MQConfig config) {
            this.Config = config;
        }

        public MQChannel CreateChannel(string queue, string routeKey, string exchangeType) {
            MQConnection conn = new MQConnection(this.Config, this.vHost);
            MQChannelManager cm = new MQChannelManager(conn);
            MQChannel channel = cm.CreateReceiveChannel(exchangeType, this.Exchange, queue, routeKey);
            return channel;
        }

        /// <summary>
        /// 啟動訂閱
        /// </summary>
        public void Start() {
            if (started)
            {
                return;
            }

            MQConnection conn = new MQConnection(this.Config, this.vHost);
            MQChannelManager manager = new MQChannelManager(conn);
            foreach (var item in this.Queues)
            {
                MQChannel channel = manager.CreateReceiveChannel(item.ExchangeType, this.Exchange, item.Queue, item.RouterKey);
                channel.OnReceivedCallback = item.OnReceived;
                this.Channels.Add(channel);
            }
            started = true;
        }

        /// <summary>
        /// 停止訂閱
        /// </summary>
        public void Stop() {
            foreach (var c in this.Channels)
            {
                c.Stop();
            }
            this.Channels.Clear();
            started = false;
        }

        /// <summary>
        /// 接收消息
        /// </summary>
        /// <param name="message"></param>
        public abstract void OnReceived(MessageBody message);

        public List<MQChannel> Channels { get; set; } = new List<MQChannel>();

        /// <summary>
        /// 消息隊列配置
        /// </summary>
        public MQConfig Config { get; set; }

        /// <summary>
        /// 消息隊列中定義的虛擬機
        /// </summary>
        public abstract string vHost { get; }

        /// <summary>
        /// 消息隊列中定義的交換機
        /// </summary>
        public abstract string Exchange { get; }

        /// <summary>
        /// 定義的隊列列表
        /// </summary>
        public List<QueueInfo> Queues { get; } = new List<QueueInfo>();
    }

           
           
           
                   
 
                    
上面的抽象類，原封不動的實現接口契約，代碼非常簡單，在 Start 方法中，創建通道和啟動消息訂閱；同時，將通道加入屬性 Channels 中，方便后面的自檢服務使用；在 Start 方法中
 
                   
 /// <summary>
        /// 啟動訂閱
        /// </summary>
        public void Start() {
            if (started)
            {
                return;
            }
        MQConnection conn = <span class="hljs-keyword">new</span> MQConnection(<span class="hljs-keyword">this</span>.Config, <span class="hljs-keyword">this</span>.vHost);
        MQChannelManager manager = <span class="hljs-keyword">new</span> MQChannelManager(conn);
        <span class="hljs-keyword">foreach</span> (<span class="hljs-keyword">var</span> item <span class="hljs-keyword">in</span> <span class="hljs-keyword">this</span>.Queues)
        {
            MQChannel channel = manager.CreateReceiveChannel(item.ExchangeType, <span class="hljs-keyword">this</span>.Exchange, item.Queue, item.RouterKey);
            channel.OnReceivedCallback = item.OnReceived;
            <span class="hljs-keyword">this</span>.Channels.Add(channel);
        }
        started = <span class="hljs-literal">true</span>;
    }</code></pre>


             
             
             
                     
 
                      
使用 MQChannelManager 創建了一個通道，並將通道的回調委托 OnReceivedCallback 設置為 item.OnReceived 方法，該方法將有子類實現；在將當前訂閱服務通道創建完成后，標記服務狀態 started 為 true，防止重復啟動；同時，在該抽象類中，不實現契約的 OnReceived(MessageBody message);強制基礎業務服務類去自我實現，因為各種業務的特殊性，這塊對消息的處理不能再基礎服務中完成
 
                     

             
             
             
                     
 
                      
接下來要介紹的是服務監控管理類，該類內部定義一個簡單的定時器功能，不間斷的對 RabbitMQ 的通訊進行偵聽，一旦發現有斷開的連接，就自動創建一個新的通道，並移除舊的通道；同時，提供 Start/Stop 兩個方法，以供程序 啟動/停止 的時候對
 
                     
2.3 RabbitMQ 的連接和通道進行清理；代碼如下
public class MQServcieManager
    {
        public int Timer_tick { get; set; } = 10 * 1000;
        private Timer timer = null;
    <span class="hljs-keyword">public</span> Action&lt;MessageLevel, <span class="hljs-keyword">string</span>, Exception&gt; OnAction = <span class="hljs-literal">null</span>;
    <span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-title">MQServcieManager</span>(<span class="hljs-params"></span>)
    </span>{
        timer = <span class="hljs-keyword">new</span> Timer(OnInterval, <span class="hljs-string">""</span>, Timer_tick, Timer_tick);
    }


    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;summary&gt;</span></span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span>  自檢，配合 RabbitMQ 內部自動重連機制</span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;/summary&gt;</span></span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;param name="sender"&gt;</span><span class="hljs-doctag">&lt;/param&gt;</span></span>
    <span class="hljs-function"><span class="hljs-keyword">private</span> <span class="hljs-keyword">void</span> <span class="hljs-title">OnInterval</span>(<span class="hljs-params"><span class="hljs-keyword">object</span> sender</span>)
    </span>{
        <span class="hljs-keyword">int</span> error = <span class="hljs-number">0</span>, reconnect = <span class="hljs-number">0</span>;
        OnAction?.Invoke(MessageLevel.Information, <span class="hljs-string">$"<span class="hljs-subst">{DateTime.Now}</span> 正在執行自檢"</span>, <span class="hljs-literal">null</span>);
        <span class="hljs-keyword">foreach</span> (<span class="hljs-keyword">var</span> item <span class="hljs-keyword">in</span> <span class="hljs-keyword">this</span>.Services)
        {
            <span class="hljs-keyword">for</span> (<span class="hljs-keyword">int</span> i = <span class="hljs-number">0</span>; i &lt; item.Channels.Count; i++)
            {
                <span class="hljs-keyword">var</span> c = item.Channels[i];
                <span class="hljs-keyword">if</span> (c.Connection == <span class="hljs-literal">null</span> || !c.Connection.IsOpen)
                {
                    error++;
                    OnAction?.Invoke(MessageLevel.Information, <span class="hljs-string">$"<span class="hljs-subst">{c.ExchangeName}</span> <span class="hljs-subst">{c.QueueName}</span> <span class="hljs-subst">{c.RoutekeyName}</span> 重新創建訂閱"</span>, <span class="hljs-literal">null</span>);
                    <span class="hljs-keyword">try</span>
                    {
                        c.Stop();
                        <span class="hljs-keyword">var</span> channel = item.CreateChannel(c.QueueName, c.RoutekeyName, c.ExchangeTypeName);
                        item.Channels.Remove(c);
                        item.Channels.Add(channel);

                        OnAction?.Invoke(MessageLevel.Information, <span class="hljs-string">$"<span class="hljs-subst">{c.ExchangeName}</span> <span class="hljs-subst">{c.QueueName}</span> <span class="hljs-subst">{c.RoutekeyName}</span> 重新創建完成"</span>, <span class="hljs-literal">null</span>);
                        reconnect++;
                    }
                    <span class="hljs-keyword">catch</span> (Exception ex)
                    {
                        OnAction?.Invoke(MessageLevel.Information, ex.Message, ex);
                    }
                }
            }
        }
        OnAction?.Invoke(MessageLevel.Information, <span class="hljs-string">$"<span class="hljs-subst">{DateTime.Now}</span> 自檢完成，錯誤數：<span class="hljs-subst">{error}</span>，重連成功數：<span class="hljs-subst">{reconnect}</span>"</span>, <span class="hljs-literal">null</span>);
    }

    <span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">Start</span>(<span class="hljs-params"></span>)
    </span>{
        <span class="hljs-keyword">foreach</span> (<span class="hljs-keyword">var</span> item <span class="hljs-keyword">in</span> <span class="hljs-keyword">this</span>.Services)
        {
            <span class="hljs-keyword">try</span>
            {
                item.Start();
            }
            <span class="hljs-keyword">catch</span> (Exception e)
            {
                OnAction?.Invoke(MessageLevel.Error, <span class="hljs-string">$"啟動服務出錯 | <span class="hljs-subst">{e.Message}</span>"</span>, e);
            }
        }
    }

    <span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">Stop</span>(<span class="hljs-params"></span>)
    </span>{
        <span class="hljs-keyword">try</span>
        {
            <span class="hljs-keyword">foreach</span> (<span class="hljs-keyword">var</span> item <span class="hljs-keyword">in</span> <span class="hljs-keyword">this</span>.Services)
            {
                item.Stop();
            }
            Services.Clear();
            timer.Dispose();
        }
        <span class="hljs-keyword">catch</span> (Exception e)
        {
            OnAction?.Invoke(MessageLevel.Error, <span class="hljs-string">$"停止服務出錯 | <span class="hljs-subst">{e.Message}</span>"</span>, e);
        }
    }

    <span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">AddService</span>(<span class="hljs-params">IService service</span>)
    </span>{
        Services.Add(service);
    }
    <span class="hljs-keyword">public</span> List&lt;IService&gt; Services { <span class="hljs-keyword">get</span>; <span class="hljs-keyword">set</span>; } = <span class="hljs-keyword">new</span> List&lt;IService&gt;();
}</code></pre>


               
               
               
                       
 
                        
代碼比較簡單，就不在一一介紹，為了將異常等內部信息傳遞到外邊，方便使用第三方組件進行日志記錄等需求，MQServcieManager 還使用了 MessageLevel 這個定義，方便業務根據不同的消息級別對消息進行處理
 
                       
    public enum MessageLevel {
        Trace = 0,
        Debug = 1,
        Information = 2,
        Warning = 3,
        Error = 4,
        Critical = 5,
        None = 6
    }
3. 開始使用

               
               
               
                       
 
                        
終於來到了這一步，我們將要開始使用這個基礎服務；首先，創建一個 DemoService 繼承自 MQServiceBase ；同時，
 
                       
3.1 實現 MQServiceBase 的抽象方法 OnReceived(MessageBody message)
 public class DemoService : MQServiceBase
    {
        public Action<MessageLevel, string, Exception> OnAction = null;
        public DemoService(MQConfig config) : base(config) {
            base.Queues.Add(new QueueInfo()
            {
                ExchangeType = ExchangeType.Direct,
                Queue = "login-message",
                RouterKey = "pk",
                OnReceived = this.OnReceived
            });
        }
    <span class="hljs-keyword">public</span> <span class="hljs-keyword">override</span> <span class="hljs-keyword">string</span> vHost { <span class="hljs-keyword">get</span> { <span class="hljs-keyword">return</span> <span class="hljs-string">"gpush"</span>; } }
    <span class="hljs-keyword">public</span> <span class="hljs-keyword">override</span> <span class="hljs-keyword">string</span> Exchange { <span class="hljs-keyword">get</span> { <span class="hljs-keyword">return</span> <span class="hljs-string">"user"</span>; } }


    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;summary&gt;</span></span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span> 接收消息</span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;/summary&gt;</span></span>
    <span class="hljs-comment"><span class="hljs-doctag">///</span> <span class="hljs-doctag">&lt;param name="message"&gt;</span><span class="hljs-doctag">&lt;/param&gt;</span></span>
    <span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">override</span> <span class="hljs-keyword">void</span> <span class="hljs-title">OnReceived</span>(<span class="hljs-params">MessageBody message</span>)
    </span>{
        <span class="hljs-keyword">try</span>
        {
            Console.WriteLine(message.Content);
        }
        <span class="hljs-keyword">catch</span> (Exception ex)
        {
            OnAction?.Invoke(MessageLevel.Error, ex.Message, ex);
        }
        message.Consumer.Model.BasicAck(message.BasicDeliver.DeliveryTag, <span class="hljs-literal">true</span>);

    }
}</code></pre>


                 
                 
                 
                         
 
                          
以上的代碼非常簡單，幾乎不需要業務開發者做更多的其它工作，開發者只需要在構造方法內部傳入一個 QueueInfo 對象，如果有多個，可一並傳入
 
                         
    public partial class QueueInfo
    {
        /// <summary>
        /// 隊列名稱
        /// </summary>
        public string Queue { get; set; }
        /// <summary>
        /// 路由名稱
        /// </summary>
        public string RouterKey { get; set; }
        /// <summary>
        /// 交換機類型
        /// </summary>
        public string ExchangeType { get; set; }
        /// <summary>
        /// 接受消息委托
        /// </summary>
        public Action<MessageBody> OnReceived { get; set; }
        /// <summary>
        /// 輸出信息到客戶端
        /// </summary>
        public Action<MQChannel, MessageLevel, string> OnAction { get; set; }
    }

                 
                 
                 
                         
 
                          
並設置 vHost 和 Exchange 的值，然后剩下的就是在 OnReceived(MessageBody message) 方法中專心的處理自己的業務了；在這里，我們僅輸出接收到的消息，並設置 ack 為已成功處理。
 
                         
4. 測試代碼
4.1 在 Program，我們執行該測試
   class Program {
        static void Main(string[] args) {
            Test();
        }
    <span class="hljs-function"><span class="hljs-keyword">static</span> <span class="hljs-keyword">void</span> <span class="hljs-title">Test</span><span class="hljs-params">()</span>
    </span>{
        MQConfig config = <span class="hljs-keyword">new</span> MQConfig()
        {
            HostName = <span class="hljs-string">"127.0.0.1"</span>,
            Password = <span class="hljs-string">"123456"</span>,
            Port = <span class="hljs-number">5672</span>,
            UserName = <span class="hljs-string">"dotnet"</span>
        };

        MQServcieManager manager = <span class="hljs-keyword">new</span> MQServcieManager();
        manager.AddService(<span class="hljs-keyword">new</span> DemoService(config));
        manager.OnAction = OnActionOutput;
        manager.Start();

        Console.WriteLine(<span class="hljs-string">"服務已啟動"</span>);
        Console.ReadKey();

        manager.Stop();
        Console.WriteLine(<span class="hljs-string">"服務已停止,按任意鍵退出..."</span>);
        Console.ReadKey();
    }

    <span class="hljs-function"><span class="hljs-keyword">static</span> <span class="hljs-keyword">void</span> <span class="hljs-title">OnActionOutput</span><span class="hljs-params">(MessageLevel level, <span class="hljs-built_in">string</span> message, Exception ex)</span>
    </span>{
        Console.ForegroundColor = ConsoleColor.Yellow;
        Console.WriteLine(<span class="hljs-string">"{0} | {1} | {2}"</span>, level, message, ex?.StackTrace);
        Console.ForegroundColor = ConsoleColor.Gray;
    }
}</code></pre>

4.2 利用 MQServcieManager 對象，完成了對所有消息訂閱者的管理和監控，

4.3 首先我們到 RabbitMQ 的 web 控制台發布一條消息到隊列 login-message 中


4.3 然后查看輸出結果


                   
                   
                   
                           
 
                            
消息已經接收並處理，為了查看監控效果，我還手動將網絡進行中斷，然后監控服務檢測到無法連接，嘗試重建通道，並將消息輸出
 
                           

                   
                   
                   
                           
 
                            
圖中步驟說明
 
                            
0：服務啟動
 
                            
1：自檢啟動
 
                            
2：服務報錯，嘗試重建，重建失敗，繼續監測
 
                            
3：RabbitMQ 內部監控自動重連，監控程序檢測到已恢復，收到消息並處理
 
                            
4：后續監控服務繼續進行監控
 
                           
結語

                   
                   
                   
                           
 
                            
在文章中，我們建立了 RabbitMQ 的通道管理、基礎服務管理、契約實現等操作，讓業務開發人員通過簡單的繼承實現去快速的處理業務系統的邏輯，后續如果有增加消費者的情況下，只需要通過 MQServcieManager.AddService 進行簡單的調用操作即可，無需對底層技術細節進行過多的改動。
 
                           
源碼下載：
 https://github.com/lianggx/EasyAspNetCoreDemo/tree/master/Ron.MQTest