NetMQ 发布订阅模式 Publisher-Subscriber

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1：简单介绍

PUB-SUB模式一般处理的都不是系统的关键数据。发布者不关注订阅者是否收到发布的消息，订阅者也不知道自己是否收到了发布者发出的所有消息。你也不知道订阅者何时开始收到消息。类似于广播，收音机。因此逻辑上，它都不是可靠的。这个可以通过与请求响应模型组合来解决。

图1：简单的发布订阅模式

图2：与请求响应模式组合的发布订阅模式

2：案例

定义IPublishser接口

namespace NetMQDemoPublisher
{
    public interface IPublisher:IDisposable
    {
        /// <summary>
        /// 发布消息
        /// </summary>
        /// <param name="topicName">主题</param>
        /// <param name="data">内容</param>
        void Publish(string topicName, string data);
    }
}

Publisher实现类

namespace NetMQDemoPublisher
{
    public class Publisher:IPublisher
    {
        private object _lockObject = new object();

        private PublisherSocket _publisherSocket;

        public Publisher(string endPoint)
        {
            _publisherSocket = new PublisherSocket();
            _publisherSocket.Options.SendHighWatermark = 1000;
            _publisherSocket.Bind(endPoint);
        }
        #region Implementation of IDisposable

        /// <summary>
        /// 执行与释放或重置非托管资源相关的应用程序定义的任务。
        /// </summary>
        public void Dispose()
        {
            lock (_lockObject)
            {
                _publisherSocket.Close();
                _publisherSocket.Dispose();
            }
        }

        /// <summary>
        /// 发布消息
        /// </summary>
        /// <param name="topicName">主题</param>
        /// <param name="data">内容</param>
        public void Publish(string topicName, string data)
        {
            lock (_lockObject)
            {
                _publisherSocket.SendMoreFrame(topicName).SendFrame(data);
            }
        }

        #endregion
    }
}

Publisher窗口界面

界面中实现的功能代码

namespace NetMQDemoPublisher
{
    public partial class PublisherForm : Form
    {
        private IPublisher publisher;
        public PublisherForm()
        {
            InitializeComponent();
            publisher = new Publisher("tcp://127.0.0.1:8888");
        }

        private void button1_Click(object sender, EventArgs e)
        {
            string strContent = textBox1.Text;
            ListViewItem item = new ListViewItem(string.Format("topic:NetMQ,Data:{0}",  strContent));
            listView1.Items.Add(item);
            publisher.Publish("NetMQ", strContent);
        }
    }
}

定义ISubscriber接口

namespace NetMQDemoSubscriber
{
    public interface ISubscriber:IDisposable
    {
        /// <summary>
        /// 事件
        /// </summary>
        event Action<string, string> Nofity;

        /// <summary>
        /// 注册订阅主题
        /// </summary>
        /// <param name="topics"></param>
        void RegisterSubscriber(List<string> topics);

        /// <summary>
        /// 注册订阅
        /// </summary>
        void RegisterSbuscriberAll();

        /// <summary>
        /// 移除所有订阅消息，并关闭
        /// </summary>
        void RemoveSbuscriberAll();
    }
}

Subscriber实现类

namespace NetMQDemoSubscriber
{
    public class Subscriber:ISubscriber
    {
        private SubscriberSocket _subscriberSocket = null;
        private string _endpoint = @"tcp://127.0.0.1:9876";

        public Subscriber(string endPoint)
        {
            _subscriberSocket = new SubscriberSocket();
            _endpoint = endPoint;
        }
        #region Implementation of IDisposable

        /// <summary>
        /// 执行与释放或重置非托管资源相关的应用程序定义的任务。
        /// </summary>
        public void Dispose()
        {
            throw new NotImplementedException();
        }

        #endregion

        #region Implementation of ISubscriber

        public event Action<string, string> Nofity = delegate { };

        /// <summary>
        /// 注册订阅主题
        /// </summary>
        /// <param name="topics"></param>
        public void RegisterSubscriber(List<string> topics)
        {
            InnerRegisterSubscriber(topics);
        }

        /// <summary>
        /// 注册订阅
        /// </summary>
        public void RegisterSbuscriberAll()
        {
            InnerRegisterSubscriber();
        }

        /// <summary>
        /// 移除所有订阅消息，并关闭
        /// </summary>
        public void RemoveSbuscriberAll()
        {
            InnerStop();
        }

        #endregion

        #region 内部实现

        /// <summary>
        /// 注册订阅消息
        /// </summary>
        /// <param name="topics">订阅的主题</param>
        private void InnerRegisterSubscriber(List<string> topics = null)
        {
            InnerStop();
            _subscriberSocket = new SubscriberSocket();
            _subscriberSocket.Options.ReceiveHighWatermark = 1000;
            _subscriberSocket.Connect(_endpoint);
            if (null == topics)
            {
                _subscriberSocket.SubscribeToAnyTopic();
            }
            else
            {
                topics.ForEach(item => _subscriberSocket.Subscribe(item));
            }
            Task.Factory.StartNew(() =>
            {
                while (true)
                {
                    string messageTopicReceived = _subscriberSocket.ReceiveFrameString();
                    string messageReceived = _subscriberSocket.ReceiveFrameString();
                    Nofity(messageTopicReceived, messageReceived);
                }
            });
        }

        /// <summary>
        /// 关闭订阅
        /// </summary>
        private void InnerStop()
        {
            _subscriberSocket.Close();
        }

        #endregion
    }
}

Subscriber窗口界面

窗体功能代码

namespace NetMQDemoSubscriber
{
    public partial class SubscriberForm : Form
    {
        private ISubscriber subscriber;
        public SubscriberForm()
        {
            InitializeComponent();
        }

        private void SubscriberForm_Load(object sender, EventArgs e)
        {
            subscriber = new Subscriber("tcp://127.0.0.1:8888");
            subscriber.RegisterSbuscriberAll();
            subscriber.Nofity+= delegate(string s, string s1)
            {
                ListViewItem item = new ListViewItem(string.Format("topic:{0},Data:{1}", s, s1));
                listView1.Items.Add(item);
            };
        }
    }
}

运行后，Publiser开启一个，Subscirber开启三个，进行测试如图

源码下载

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