簡單易用的.NET免費開源RabbitMQ操作元件EasyNetQ解析
對於目前大多的.NET專案，其實使用的技術棧都是差不多，估計現在很少用控制元件開發專案的了，畢竟一大堆問題。對.NET的專案，目前比較適合的架構ASP.NET MVC，ASP.NET WebAPI，ORM（較多Dapper.NET或者其擴充套件，稍大一些的專案用EF等等），為了提高速度也會採用快取（.NET自帶的Memcache，或者Redis），請求較多的專案，使用Nginx做負載均衡和使用佇列等等。
上面簡單的介紹一下.NET的專案的技術架構，具體的技術根據具體的需求做出選擇。介紹到佇列，很多人都會很熟悉，例如MSMQ，RabbitMQ等等佇列。既然需要使用佇列，那就要考慮如何使用C#更好的操作佇列。
一.RabbitMQ概述
在現在的專案中，訊息佇列的使用比較的頻繁，訊息佇列的種類也較多，如：ActiveMQ，RabbitMQ，ZeroMQ，Kafka，MetaMQ，RocketMQ等。訊息佇列中介軟體是分散式系統中重要的元件，主要解決應用耦合，非同步訊息，流量削鋒等問題。實現高效能，高可用，可伸縮和最終一致性架構。是大型分散式系統不可缺少的中介軟體。
在這裡主要介紹RabbitMQ訊息佇列，支援開放的高階訊息佇列協議 (AMQP)。RabbitMQ的特點：強大的應用程式訊息傳遞；使用方便；執行在所有主要作業系統上；支援大量開發人員平臺；開源和商業支援。訊息佇列的模式有兩種模式：P2P（Point to Point），P2P模式包含三個角色：訊息佇列（Queue），傳送者(Sender)，接收者(Receiver)。每個訊息都被髮送到一個特定的佇列，接收者從佇列中獲取訊息。佇列保留著訊息，直到他們被消費或超時。Publish/Subscribe(Pub/Sub)，包含三個角色主題（Topic），釋出者（Publisher），訂閱者（Subscriber） 。多個釋出者將訊息傳送到Topic,系統將這些訊息傳遞給多個訂閱者。
上面介紹了RabbitMQ的相關特點和模式，更多的知識就不再介紹，需要了解安裝和配置，可以進入官網進行細緻的瞭解。
二.EasyNetQ元件概述
上面介紹了RabbitMQ的應用場景和使用的模式，在.NET的專案開發中，較多的使用MSMQ作為訊息佇列，很多人對於MSMQ的操作比較熟悉，也屬於輕量級的訊息佇列。對於RabbitMQ是較為重量級的訊息佇列，有多個語言的版本，作為.NET開發者對於RabbitMQ的操作可能就比較少。在.NET專案中如何更方便的使用RabbitMQ，在這裡就介紹一個.NET操作RabbitMQ的元件EasyNetQ。
EasyNetQ的目標是提供一個使.NET中的RabbitMQ儘可能簡單的庫。在EasyNetQ中訊息應由.NET型別表示，訊息應通過其.NET型別進行路由。EasyNetQ按訊息型別進行路由。釋出訊息時，EasyNetQ會檢查其型別，並根據型別名稱，名稱空間和裝配體給出一個路由金鑰。在消費方面，使用者訂閱型別。訂閱型別後，該型別的訊息將路由到訂戶。預設情況下，EasyNetQ使用Newtonsoft.Json庫將.NET型別序列化為JSON。這具有訊息是人類可讀的優點，因此您可以使用RabbitMQ管理應用程式等工具來除錯訊息問題。
EasyNetQ是在RabbitMQ.Client庫之上提供服務的元件集合。這些操作可以像序列化，錯誤處理，執行緒編組，連線管理等。它們由mini-IoC容器組成。您可以輕鬆地用自己的實現替換任何元件。因此，如果您希望XML序列化而不是內建的JSON，只需編寫一個ISerializer的實現並將其註冊到容器。
以下是官方提供的一個結構圖，這個結構圖可以很好的解析該元件的結構：
三.EasyNetQ元件使用方式
介紹完畢EasyNetQ元件的相關背景，現在就要介紹一下該元件的使用方式。EasyNetQ元件的使用方式比較簡單，跟很多元件都類似，例如：建立連線，進行操作做等等，對於EasyNetQ元件也是如此。
1.建立連線：
var bus = RabbitHutch.CreateBus(“host=myServer;virtualHost=myVirtualHost;username=mike;password=topsecret”);
與RabbitMQ伺服器的延遲連線由IBus介面表示，建立連線的方式連線字串由格式為key = value的鍵/值對組成，每一個用分號（;）分隔。host：主機地址；virtualHost：預設是預設的虛擬主機’/’；username：使用者名稱，預設為’guest’；password：密碼，預設是’guest’；
2.關閉連線：
bus.Dispose();
要關閉連線，只需簡單地處理匯流排，這將關閉EasyNetQ使用的連線，渠道，消費者和所有其他資源。
3.釋出訊息：
var message = new MyMessage { Text = "Hello Rabbit" };
bus.Publish(message);
4.訂閱郵件：
bus.Subscribe<MyMessage>("my_subscription_id", msg => Console.WriteLine(msg.Text));
5.遠端過程呼叫：
var request = new TestRequestMessage {Text = "Hello from the client! "};
bus.Request<TestRequestMessage, TestResponseMessage>(request, response => Console.WriteLine("Got response: '{0}'",response.Text));
6.RPC伺服器：
bus.Respond<TestRequestMessage, TestResponseMessage>(request => new TestResponseMessage{ Text = request.Text + " all done!" });
7.記錄器：
var logger = new MyLogger() ;
var bus = RabbitHutch.CreateBus(“my connection string”, x => x.Register<IEasyNetQLogger>(_ => logger));
8.路由：
bus.Subscribe("my_id", handler, x => x.WithTopic("X.*"));
RabbitMQ具有非常好的功能，基於主題的路由，允許訂閱者基於多個標準過濾訊息。*（星號）匹配一個字。＃（雜湊）匹配為零個或多個單詞。
四.EasyNetQ元件核心物件解析
上面簡單的介紹了一下該元件的應用方式，還有比較多的方式沒有做介紹，又需要的可以做深入的瞭解。在這裡介紹一下該元件的一些核心的物件。
1.RabbitHutch.CreateBus()：
舊版方法
public static IBus CreateBus(ConnectionConfiguration connectionConfiguration, AdvancedBusEventHandlers advancedBusEventHandlers,
Action<IServiceRegister> registerServices)
{
Preconditions.CheckNotNull(connectionConfiguration, "connectionConfiguration");
Preconditions.CheckNotNull(advancedBusEventHandlers, "advancedBusEventHandlers");
Preconditions.CheckNotNull(registerServices, "registerServices");
var container = createContainerInternal();
if (container == null)
{
throw new EasyNetQException("Could not create container. " +
"Have you called SetContainerFactory(...) with a function that returns null?");
}
connectionConfiguration.Validate();
container.Register(_ => connectionConfiguration);
container.Register(_ => advancedBusEventHandlers);
registerServices(container);
ComponentRegistration.RegisterServices(container);
return container.Resolve<IBus>();
}
在RabbitHutch類中主要包含的方法是CreateBus()方法，具有12個過載。該方法主要根據使用者的連線配置資訊，連線服務端。該方法接收三個引數，connectionConfiguration表示連線例項，advancedBusEventHandlers用於新增處理程式的AdvancedBusEventHandlers例項到新建立的IBus.Advanced”的事件。registerServices覆蓋預設服務。 ComponentRegistration.RegisterServices(container);在我們內部的超簡單IoC容器中註冊預設的EasyNetQ元件。container.Resolve<IBus>()獲取所請求的服務的例項。 注意所有服務都是單例的，多次通話Resolve將返回相同的例項。
EasyNetQ 3.3.4 新版
RabbitHutch.cs
using System;
using System.Collections.Generic;
#if NETFX
using System.Configuration;
#endif
using EasyNetQ.ConnectionString;
using EasyNetQ.DI;
namespace EasyNetQ
{
/// <summary>
/// Static methods to create EasyNetQ core APIs.
/// </summary>
public static class RabbitHutch
{
#if NETFX
/// <summary>
/// Creates a new instance of <see cref="RabbitBus"/>.
/// The RabbitMQ broker is defined in the connection string named 'rabbit'.
/// </summary>
/// <param name="registerServices">
/// Override default services. For example, to override the default <see cref="ISerializer"/>:
/// RabbitHutch.CreateBus("host=localhost", x => x.Register{ISerializer}(mySerializer));
/// </param>
/// <returns>
/// A new <see cref="RabbitBus"/> instance.
/// </returns>
public static IBus CreateBus(Action<IServiceRegister> registerServices)
{
var rabbitConnection = ConfigurationManager.ConnectionStrings["rabbit"];
if (rabbitConnection == null)
{
throw new EasyNetQException(
"Could not find a connection string for RabbitMQ. " +
"Please add a connection string in the <ConnectionStrings> section" +
"of the application's configuration file. For example: " +
"<add name=\"rabbit\" connectionString=\"host=localhost\" />");
}
var rabbitConnectionString = rabbitConnection.ConnectionString;
return CreateBus(rabbitConnectionString, registerServices);
}
/// <summary>
/// Creates a new instance of <see cref="RabbitBus"/>.
/// The RabbitMQ broker is defined in the connection string named 'rabbit'.
/// </summary>
/// <returns>
/// A new <see cref="RabbitBus"/> instance.
/// </returns>
public static IBus CreateBus()
{
return CreateBus(c => {});
}
#endif
/// <summary>
/// Creates a new instance of <see cref="RabbitBus"/>.
/// </summary>
/// <param name="connectionString">
/// The EasyNetQ connection string. Example:
/// host=192.168.1.1;port=5672;virtualHost=MyVirtualHost;username=MyUsername;password=MyPassword;requestedHeartbeat=10
///
/// The following default values will be used if not specified:
/// host=localhost;port=5672;virtualHost=/;username=guest;password=guest;requestedHeartbeat=10
/// </param>
/// <returns>
/// A new <see cref="RabbitBus"/> instance.
/// </returns>
public static IBus CreateBus(string connectionString)
{
return CreateBus(connectionString, x => { });
}
/// <summary>
/// Creates a new instance of <see cref="RabbitBus"/>.
/// </summary>
/// <param name="connectionString">
/// The EasyNetQ connection string. Example:
/// host=192.168.1.1;port=5672;virtualHost=MyVirtualHost;username=MyUsername;password=MyPassword;requestedHeartbeat=10
///
/// The following default values will be used if not specified:
/// host=localhost;port=5672;virtualHost=/;username=guest;password=guest;requestedHeartbeat=10
/// </param>
/// <param name="registerServices">
/// Override default services. For example, to override the default <see cref="ISerializer"/>:
/// RabbitHutch.CreateBus("host=localhost", x => x.Register{ISerializer}(mySerializer));
/// </param>
/// <returns>
/// A new <see cref="RabbitBus"/> instance.
/// </returns>
public static IBus CreateBus(string connectionString, Action<IServiceRegister> registerServices)
{
Preconditions.CheckNotNull(connectionString, "connectionString");
return CreateBus(x => x.Resolve<IConnectionStringParser>().Parse(connectionString), registerServices);
}
/// <summary>
/// Creates a new instance of <see cref="RabbitBus"/>.
/// </summary>
/// <param name="hostName">
/// The RabbitMQ broker.
/// </param>
/// <param name="hostPort">
/// The RabbitMQ broker port.
/// </param>
/// <param name="virtualHost">
/// The RabbitMQ virtualHost.
/// </param>
/// <param name="username">
/// The username to use to connect to the RabbitMQ broker.
/// </param>
/// <param name="password">
/// The password to use to connect to the RabbitMQ broker.
/// </param>
/// <param name="requestedHeartbeat">
/// The initially requested heartbeat interval, in seconds; zero for none.
/// </param>
/// <param name="registerServices">
/// Override default services. For example, to override the default <see cref="ISerializer"/>:
/// RabbitHutch.CreateBus("host=localhost", x => x.Register{ISerializer}(mySerializer));
/// </param>
/// <returns>
/// A new <see cref="RabbitBus"/> instance.
/// </returns>
public static IBus CreateBus(
string hostName,
ushort hostPort,
string virtualHost,
string username,
string password,
ushort requestedHeartbeat,
Action<IServiceRegister> registerServices)
{
Preconditions.CheckNotNull(hostName, "hostName");
Preconditions.CheckNotNull(virtualHost, "virtualHost");
Preconditions.CheckNotNull(username, "username");
Preconditions.CheckNotNull(password, "password");
var connectionConfiguration = new ConnectionConfiguration
{
Hosts = new List<HostConfiguration>
{
new HostConfiguration { Host = hostName, Port = hostPort }
},
Port = hostPort,
VirtualHost = virtualHost,
UserName = username,
Password = password,
RequestedHeartbeat = requestedHeartbeat
};
return CreateBus(connectionConfiguration, registerServices);
}
/// <summary>
/// Creates a new instance of <see cref="RabbitBus"/>.
/// </summary>
/// <param name="connectionConfiguration">
/// An <see cref="ConnectionConfiguration"/> instance.
/// </param>
/// <param name="registerServices">
/// Override default services. For example, to override the default <see cref="ISerializer"/>:
/// RabbitHutch.CreateBus("host=localhost", x => x.Register{ISerializer}(mySerializer));
/// </param>
/// <returns>
/// A new <see cref="RabbitBus"/> instance.
/// </returns>
public static IBus CreateBus(ConnectionConfiguration connectionConfiguration, Action<IServiceRegister> registerServices)
{
Preconditions.CheckNotNull(connectionConfiguration, "connectionConfiguration");
return CreateBus(_ => connectionConfiguration, registerServices);
}
/// <summary>
/// Creates a new instance of <see cref="RabbitBus"/>.
/// </summary>
/// <param name="connectionConfigurationFactory">
/// A factory of <see cref="ConnectionConfiguration"/> instance.
/// </param>
/// <param name="registerServices">
/// Override default services. For example, to override the default <see cref="ISerializer"/>:
/// RabbitHutch.CreateBus("host=localhost", x => x.Register{ISerializer}(mySerializer));
/// </param>
/// <returns>
/// A new <see cref="RabbitBus"/> instance.
/// </returns>
public static IBus CreateBus(Func<IServiceResolver, ConnectionConfiguration> connectionConfigurationFactory, Action<IServiceRegister> registerServices)
{
var container = new DefaultServiceContainer();
RegisterBus(container, connectionConfigurationFactory, registerServices);
return container.Resolve<IBus>();
}
/// <summary>
/// Registers components of a <see cref="RabbitBus"/>.
/// </summary>
/// <param name="serviceRegister"/>
/// <param name="connectionConfigurationFactory">
/// A factory of <see cref="ConnectionConfiguration"/> instance.
/// </param>
/// <param name="registerServices">
/// Override default services. For example, to override the default <see cref="ISerializer"/>:
/// RabbitHutch.CreateBus("host=localhost", x => x.Register{ISerializer}(mySerializer));
/// </param>
/// <returns>
/// A new <see cref="RabbitBus"/> instance.
/// </returns>
public static void RegisterBus(IServiceRegister serviceRegister,
Func<IServiceResolver, ConnectionConfiguration> connectionConfigurationFactory,
Action<IServiceRegister> registerServices)
{
Preconditions.CheckNotNull(serviceRegister, "serviceRegister");
Preconditions.CheckNotNull(connectionConfigurationFactory, "connectionConfiguration");
Preconditions.CheckNotNull(registerServices, "registerServices");
serviceRegister.Register(c =>
{
var connectionConfiguration = connectionConfigurationFactory.Invoke(c);
connectionConfiguration.Validate();
return connectionConfiguration;
});
serviceRegister.RegisterDefaultServices();
registerServices(serviceRegister);
}
}
}
IBus介面
using System;
using EasyNetQ.Producer;
using EasyNetQ.Scheduling;
namespace EasyNetQ
{
/// <summary>
/// Provides a simple Publish/Subscribe, Request/Response, Send/Receive and Delayed Publish API for a message bus.為訊息匯流排提供簡單的釋出/訂閱，請求/響應，傳送/接收和延遲釋出API。
/// </summary>
public interface IBus : IDisposable
{
/// <summary>
/// Provides a simple Publish/Subscribe API
///提供簡單的釋出/訂閱API
/// </summary>
IPubSub PubSub { get; }
/// <summary>
/// Provides a simple Request/Response API
///提供簡單的請求/響應API
/// </summary>
IRpc Rpc { get; }
/// <summary>
/// Provides a simple Send/Receive API
///提供簡單的傳送/接收API
/// </summary>
ISendReceive SendReceive { get; }
/// <summary>
/// Provides a simple Delayed Publish API
///提供簡單的延遲釋出API
/// </summary>
IScheduler Scheduler { get; }
/// <summary>
/// Return the advanced EasyNetQ advanced API.
///返回高階EasyNetQ高階API
/// </summary>
IAdvancedBus Advanced { get; }
}
}
2.IBus.Publish()：
舊版本的方法
public virtual void Publish<T>(T message, Action<IPublishConfiguration> configure) where T : class
{
Preconditions.CheckNotNull(message, "message");
Preconditions.CheckNotNull(configure, "configure");
var configuration = new PublishConfiguration(conventions.TopicNamingConvention(typeof(T)));
configure(configuration);
var messageType = typeof(T);
var easyNetQMessage = new Message<T>(message)
{
Properties =
{
DeliveryMode = messageDeliveryModeStrategy.GetDeliveryMode(messageType)
}
};
if (configuration.Priority != null)
easyNetQMessage.Properties.Priority = configuration.Priority.Value;
if (configuration.Expires != null)
easyNetQMessage.Properties.Expiration = configuration.Expires.ToString();
var exchange = publishExchangeDeclareStrategy.DeclareExchange(advancedBus, messageType, ExchangeType.Topic);
advancedBus.Publish(exchange, configuration.Topic, false, easyNetQMessage);
}
該方法用於釋出訊息，該方法是一個虛方法，在子類中可以被重寫。 var configuration = new PublishConfiguration(conventions.TopicNamingConvention(typeof(T)))用於定義釋出資訊的配置，Message定義郵件正文內容。
EasyNetQ 3.3.4 新版
PubSubExtensions擴充套件類
using System;
using System.Threading;
using System.Threading.Tasks;
using EasyNetQ.FluentConfiguration;
using EasyNetQ.Internals;
namespace EasyNetQ.Producer
{
public static class PubSubExtensions
{
/// <summary>
/// Publishes a message with a topic.
/// When used with publisher confirms the task completes when the publish is confirmed.
/// Task will throw an exception if the confirm is NACK'd or times out.
/// </summary>
/// <typeparam name="T">The message type</typeparam>
/// <param name="pubSub">The pubSub instance</param>
/// /// <param name="message">The message to publish</param>
/// <param name="cancellationToken">The cancellation token</param>
/// <returns></returns>
public static Task PublishAsync<T>(this IPubSub pubSub, T message, CancellationToken cancellationToken = default)
{
Preconditions.CheckNotNull(pubSub, "pubSub");
return pubSub.PublishAsync(message, c => {}, cancellationToken);
}
/// <summary>
/// Publishes a message with a topic.
/// When used with publisher confirms the task completes when the publish is confirmed.
/// Task will throw an exception if the confirm is NACK'd or times out.
/// </summary>
/// <typeparam name="T">The message type</typeparam>
/// <param name="pubSub">The pubSub instance</param>
/// /// <param name="message">The message to publish</param>
/// <param name="topic">The topic string</param>
/// <param name="cancellationToken">The cancellation token</param>
/// <returns></returns>
public static Task PublishAsync<T>(this IPubSub pubSub, T message, string topic, CancellationToken cancellationToken = default)
{
Preconditions.CheckNotNull(pubSub, "pubSub");
Preconditions.CheckNotNull(topic, "topic");
return pubSub.PublishAsync(message, c => c.WithTopic(topic), cancellationToken);
}
/// <summary>
/// Publishes a message.
/// </summary>
/// <typeparam name="T">The message type</typeparam>
/// <param name="pubSub">The pubSub instance</param>
/// <param name="message">The message to publish</param>
/// <param name="cancellationToken">The cancellation token</param>
public static void Publish<T>(this IPubSub pubSub, T message, CancellationToken cancellationToken = default)
{
Preconditions.CheckNotNull(pubSub, "pubSub");
pubSub.Publish(message, c => { }, cancellationToken);
}
/// <summary>
/// Publishes a message.
/// </summary>
/// <typeparam name="T">The message type</typeparam>
/// <param name="pubSub">The pubSub instance</param>
/// <param name="message">The message to publish</param>
/// <param name="configure">
/// Fluent configuration e.g. x => x.WithTopic("*.brighton").WithPriority(2)
/// </param>
/// <param name="cancellationToken">The cancellation token</param>
public static void Publish<T>(this IPubSub pubSub, T message, Action<IPublishConfiguration> configure, CancellationToken cancellationToken = default)
{
Preconditions.CheckNotNull(pubSub, "pubSub");
pubSub.PublishAsync(message, configure, cancellationToken)
.GetAwaiter()
.GetResult();
}
/// <summary>
/// Publishes a message with a topic
/// </summary>
/// <typeparam name="T">The message type</typeparam>
/// <param name="pubSub">The pubSub instance</param>
/// <param name="message">The message to publish</param>
/// <param name="topic">The topic string</param>
/// <param name="cancellationToken">The cancellation token</param>
public static void Publish<T>(this IPubSub pubSub, T message, string topic, CancellationToken cancellationToken = default)
{
Preconditions.CheckNotNull(pubSub, "pubSub");
pubSub.Publish(message, c => c.WithTopic(topic), cancellationToken);
}
/// <summary>
/// Subscribes to a stream of messages that match a .NET type.
/// </summary>
/// <typeparam name="T">The type to subscribe to</typeparam>
/// <param name="pubSub">The pubSub instance</param>
/// <param name="subscriptionId">
/// A unique identifier for the subscription. Two subscriptions with the same subscriptionId
/// and type will get messages delivered in turn. This is useful if you want multiple subscribers
/// to load balance a subscription in a round-robin fashion.
/// </param>
/// <param name="onMessage">
/// The action to run when a message arrives. When onMessage completes the message
/// receipt is Ack'd. All onMessage delegates are processed on a single thread so you should
/// avoid long running blocking IO operations. Consider using SubscribeAsync
/// </param>
/// <param name="cancellationToken">The cancellation token</param>
/// <returns>
/// An <see cref="ISubscriptionResult"/>
/// Call Dispose on it or on its <see cref="ISubscriptionResult.ConsumerCancellation"/> to cancel the subscription.
/// </returns>
public static AwaitableDisposable<ISubscriptionResult> SubscribeAsync<T>(
this IPubSub pubSub,
string subscriptionId,
Action<T> onMessage,
CancellationToken cancellationToken = default
)
{
Preconditions.CheckNotNull(pubSub, "pubSub");
return pubSub.SubscribeAsync(
subscriptionId,
onMessage,
c => { },
cancellationToken
);
}
/// <summary>
/// Subscribes to a stream of messages that match a .NET type.
/// </summary>
/// <typeparam name="T">The type to subscribe to</typeparam>
/// <param name="pubSub">The pubSub instance</param>
/// <param name="subscriptionId">
/// A unique identifier for the subscription. Two subscriptions with the same subscriptionId
/// and type will get messages delivered in turn. This is useful if you want multiple subscribers
/// to load balance a subscription in a round-robin fashion.
/// </param>
/// <param name="onMessage">
/// The action to run when a message arrives. When onMessage completes the message
/// receipt is Ack'd. All onMessage delegates are processed on a single thread so you should
/// avoid long running blocking IO operations. Consider using SubscribeAsync
/// </param>
/// <param name="configure">
/// Fluent configuration e.g. x => x.WithTopic("uk.london")
/// </param>
/// <param name="cancellationToken">The cancellation token</param>
/// <returns>
/// An <see cref="ISubscriptionResult"/>
/// Call Dispose on it or on its <see cref="ISubscriptionResult.ConsumerCancellation"/> to cancel the subscription.
/// </returns>
public static AwaitableDisposable<ISubscriptionResult> SubscribeAsync<T>(
this IPubSub pubSub,
string subscriptionId,
Action<T> onMessage,
Action<ISubscriptionConfiguration> configure,
CancellationToken cancellationToken = default
)
{
Preconditions.CheckNotNull(pubSub, "pubSub");
var onMessageAsync = TaskHelpers.FromAction<T>((m, c) => onMessage(m));
return pubSub.SubscribeAsync(
subscriptionId,
onMessageAsync,
configure,
cancellationToken
);
}
/// <summary>
/// Subscribes to a stream of messages that match a .NET type.
/// Allows the subscriber to complete asynchronously.
/// </summary>
/// <typeparam name="T">The type to subscribe to</typeparam>
/// <param name="pubSub">The pubSub instance</param>
/// <param name="subscriptionId">
/// A unique identifier for the subscription. Two subscriptions with the same subscriptionId
/// and type will get messages delivered in turn. This is useful if you want multiple subscribers
/// to load balance a subscription in a round-robin fashion.
/// </param>
/// <param name="onMessage">
/// The action to run when a message arrives. onMessage can immediately return a Task and
/// then continue processing asynchronously. When the Task completes the message will be
/// Ack'd.
/// </param>
/// <param name="cancellationToken">The cancellation token</param>
/// <returns>
/// An <see cref="ISubscriptionResult"/>
/// Call Dispose on it or on its <see cref="ISubscriptionResult.ConsumerCancellation"/> to cancel the subscription.
/// </returns>
public static AwaitableDisposable<ISubscriptionResult> SubscribeAsync<T>(
IPubSub pubSub,
string subscriptionId,
Func<T, Task> onMessage,
CancellationToken cancellationToken = default
)
{
Preconditions.CheckNotNull(pubSub, "pubSub");
return pubSub.SubscribeAsync<T>(
subscriptionId,
(m, c) => onMessage(m),
c => { },
cancellationToken
);
}
/// <summary>
/// Subscribes to a stream of messages that match a .NET type.
/// </summary>
/// <typeparam name="T">The type to subscribe to</typeparam>
/// <param name="pubSub">The pubSub instance</param>
/// <param name="subscriptionId">
/// A unique identifier for the subscription. Two subscriptions with the same subscriptionId
/// and type will get messages delivered in turn. This is useful if you want multiple subscribers
/// to load balance a subscription in a round-robin fashion.
/// </param>
/// <param name="onMessage">
/// The action to run when a message arrives. When onMessage completes the message
/// receipt is Ack'd. All onMessage delegates are processed on a single thread so you should
/// avoid long running blocking IO operations. Consider using SubscribeAsync
/// </param>
/// <param name="cancellationToken">The cancellation token</param>
/// <returns>
/// An <see cref="ISubscriptionResult"/>
/// Call Dispose on it or on its <see cref="ISubscriptionResult.ConsumerCancellation"/> to cancel the subscription.
/// </returns>
public static ISubscriptionResult Subscribe<T>(
this IPubSub pubSub,
string subscriptionId,
Action<T> onMessage,
CancellationToken cancellationToken = default
)
{
Preconditions.CheckNotNull(pubSub, "pubSub");
return pubSub.Subscribe(
subscriptionId,
onMessage,
c => { },
cancellationToken
);
}
/// <summary>
/// Subscribes to a stream of messages that match a .NET type.
/// </summary>
/// <typeparam name="T">The type to subscribe to</typeparam>
/// <param name="pubSub">The pubSub instance</param>
/// <param name="subscriptionId">
/// A unique identifier for the subscription. Two subscriptions with the same subscriptionId
/// and type will get messages delivered in turn. This is useful if you want multiple subscribers
/// to load balance a subscription in a round-robin fashion.
/// </param>
/// <param name="onMessage">
/// The action to run when a message arrives. When onMessage completes the message
/// receipt is Ack'd. All onMessage delegates are processed on a single thread so you should
/// avoid long running blocking IO operations. Consider using SubscribeAsync
/// </param>
/// <param name="configure">
/// Fluent configuration e.g. x => x.WithTopic("uk.london")
/// </param>
/// <param name="cancellationToken">The cancellation token</param>
/// <returns>
/// An <see cref="ISubscriptionResult"/>
/// Call Dispose on it or on its <see cref="ISubscriptionResult.ConsumerCancellation"/> to cancel the subscription.
/// </returns>
public static ISubscriptionResult Subscribe<T>(
this IPubSub pubSub,
string subscriptionId,
Action<T> onMessage,
Action<ISubscriptionConfiguration> configure,
CancellationToken cancellationToken = default
)
{
Preconditions.CheckNotNull(pubSub, "pubSub");
var onMessageAsync = TaskHelpers.FromAction<T>((m, c) => onMessage(m));
return pubSub.Subscribe(
subscriptionId,
onMessageAsync,
configure,
cancellationToken
);
}
/// <summary>
/// Subscribes to a stream of messages that match a .NET type.
/// Allows the subscriber to complete asynchronously.
/// </summary>
/// <typeparam name="T">The type to subscribe to</typeparam>
/// <param name="pubSub">The pubSub instance</param>
/// <param name="subscriptionId">
/// A unique identifier for the subscription. Two subscriptions with the same subscriptionId
/// and type will get messages delivered in turn. This is useful if you want multiple subscribers
/// to load balance a subscription in a round-robin fashion.
/// </param>
/// <param name="onMessage">
/// The action to run when a message arrives. onMessage can immediately return a Task and
/// then continue processing asynchronously. When the Task completes the message will be
/// Ack'd.
/// </param>
/// <param name="cancellationToken">The cancellation token</param>
/// <returns>
/// An <see cref="ISubscriptionResult"/>
/// Call Dispose on it or on its <see cref="ISubscriptionResult.ConsumerCancellation"/> to cancel the subscription.
/// </returns>
public static ISubscriptionResult Subscribe<T>(
IPubSub pubSub,
string subscriptionId,
Func<T, Task> onMessage,
CancellationToken cancellationToken = default
)
{
Preconditions.CheckNotNull(pubSub, "pubSub");
return pubSub.Subscribe<T>(
subscriptionId,
(m, c) => onMessage(m),
c => { },
cancellationToken
);
}
/// <summary>
/// Subscribes to a stream of messages that match a .NET type.
/// Allows the subscriber to complete asynchronously.
/// </summary>
/// <typeparam name="T">The type to subscribe to</typeparam>
/// <param name="pubSub">The pubSub instance</param>
/// <param name="subscriptionId">
/// A unique identifier for the subscription. Two subscriptions with the same subscriptionId
/// and type will get messages delivered in turn. This is useful if you want multiple subscribers
/// to load balance a subscription in a round-robin fashion.
/// </param>
/// <param name="onMessage">
/// The action to run when a message arrives. onMessage can immediately return a Task and
/// then continue processing asynchronously. When the Task completes the message will be
/// Ack'd.
/// </param>
/// <param name="configure">
/// Fluent configuration e.g. x => x.WithTopic("uk.london")
/// </param>
/// <param name="cancellationToken">The cancellation token</param>
/// <returns>
/// An <see cref="ISubscriptionResult"/>
/// Call Dispose on it or on its <see cref="ISubscriptionResult.ConsumerCancellation"/> to cancel the subscription.
/// </returns>
public static ISubscriptionResult Subscribe<T>(
this IPubSub pubSub,
string subscriptionId,
Func<T, CancellationToken, Task> onMessage,
Action<ISubscriptionConfiguration> configure,
CancellationToken cancellationToken = default
)
{
Preconditions.CheckNotNull(pubSub, "pubSub");
return pubSub.SubscribeAsync(
subscriptionId,
onMessage,
configure,
cancellationToken
).GetAwaiter().GetResult();
}
}
}
五.總結
以上是對該元件的簡單的介紹，如果需要了解更多的內容可以自己去深入的學習和研究。知識在於自己的勤奮，他人只是一個簡單的引導。
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