这两天工作项目中用到了rabbitmq，顺便学习了一下。
RabbitMq主要的使用模式有三种：工作队列，发布订阅和RPC远程调用。
1.工作队列
生产者：
using System;
using RabbitMQ.Client;
using System.Text; class NewTask
{
public static void Main(string[] args)
{
var factory = new ConnectionFactory() { HostName = "localhost" };
using(var connection = factory.CreateConnection())
using(var channel = connection.CreateModel())
{
//一定要声明队列，向队列发送消息
channel.QueueDeclare(queue: "task_queue",
durable: true, //队列是否持久化
exclusive: false,
autoDelete: false,
arguments: null); var message = GetMessage(args);
var body = Encoding.UTF8.GetBytes(message); var properties = channel.CreateBasicProperties();
properties.SetPersistent(true); //消息是否持久化 channel.BasicPublish(exchange: "", //没有定义exchange，会使用系统默认的exchange
routingKey: "task_queue",
basicProperties: properties,
body: body);
Console.WriteLine(" [x] Sent {0}", message);
} Console.WriteLine(" Press [enter] to exit.");
Console.ReadLine();
} private static string GetMessage(string[] args)
{
return ((args.Length > ) ? string.Join(" ", args) : "Hello World!");
}
}
在方法
channel.BasicPublish("", "task_queue", null, bytes);中的第一个参数是需要输入一个exchange。在RabbitMQ中，所有的消息都必须要通过exchange发送到各个queue里面去。发送者发送消息，其实也就是把消息放到exchange中去。而exchange知道应该把消息放到哪里去。在这个方法中，我们没有输入exchange的名称，只是定义了一个空的echange，而在第二个参数routeKey中输入了我们目标队列的名称。RabbitMQ会帮我定义一个默认的exchange，这个exchange会把消息直接投递到
我们输入的队列中，这样服务端只需要直接去这个定义了的队列中获取消息就可以了。
消费者：
using System;
using RabbitMQ.Client;
using RabbitMQ.Client.Events;
using System.Text;
using System.Threading; class Worker
{
public static void Main()
{
var factory = new ConnectionFactory() { HostName = "localhost" };
using(var connection = factory.CreateConnection())
using(var channel = connection.CreateModel())
{
channel.QueueDeclare(queue: "task_queue",
durable: true,
exclusive: false,
autoDelete: false,
arguments: null); //修改分发机制(原先是轮询分发)， prefetchCount = 1 变为 不向正在处理的worker发发任务，谁先有空就给谁
//In order to defeat that we can use the basicQos method with the prefetchCount = 1 setting.
//This tells RabbitMQ not to give more than one message to a worker at a time.
//Or, in other words, don't dispatch a new message to a worker until it has processed and acknowledged the previous one.
//Instead, it will dispatch it to the next worker that is not still busy.
channel.BasicQos(prefetchSize: , prefetchCount: , global: false); Console.WriteLine(" [*] Waiting for messages."); var consumer = new EventingBasicConsumer(channel);
consumer.Received += (model, ea) =>
{
var body = ea.Body;
var message = Encoding.UTF8.GetString(body);
Console.WriteLine(" [x] Received {0}", message); int dots = message.Split('.').Length - ;
Thread.Sleep(dots * ); Console.WriteLine(" [x] Done");
//当noAck为false起作用，手动告知应答处理完成
channel.BasicAck(deliveryTag: ea.DeliveryTag, multiple: false);
};
channel.BasicConsume(queue: "task_queue",
noAck: false, //是否不要手动应答(no manual Ack)，ture自动应答，自动删除处理消息；false手动应答，服务器的消息会等待应答结果才消除
consumer: consumer); Console.WriteLine(" Press [enter] to exit.");
Console.ReadLine();
}
}
}
这里要注意的，如果没有宿主进程，比如一个Console的后台程序，这个 Console.ReadLine(); 不能少，而且一定要加在这里。否则:
1.程序自动退出。2.相关的变量出了生命周期范围，已经释放！笔者在这里吃过亏，找了半天才发现。
2.发布订阅
Exchange类型为四种:direct，fanout，topic，headers。此模式中，由于是通过exchange和routingkey发送给多个队列，所以Publish中不用声明队列，只需声明exchange。
1、Routing - Exchange类型direct
他是根据交换器名称与routingkey来找队列的。
Publish:
using System;
using System.Linq;
using RabbitMQ.Client;
using System.Text; class EmitLogDirect
{
public static void Main(string[] args)
{
var factory = new ConnectionFactory() { HostName = "localhost" };
using(var connection = factory.CreateConnection())
using(var channel = connection.CreateModel())
{
channel.ExchangeDeclare(exchange: "direct_logs",
type: "direct"); var severity = (args.Length > ) ? args[] : "info";
var message = (args.Length > )
? string.Join(" ", args.Skip( ).ToArray())
: "Hello World!";
var body = Encoding.UTF8.GetBytes(message);
channel.BasicPublish(exchange: "direct_logs",
routingKey: severity, //传来参数，指定的routekey
basicProperties: null,
body: body);
Console.WriteLine(" [x] Sent '{0}':'{1}'", severity, message);
} Console.WriteLine(" Press [enter] to exit.");
Console.ReadLine();
}
}
subscribe
using System;
using RabbitMQ.Client;
using RabbitMQ.Client.Events;
using System.Text; class ReceiveLogsDirect
{
public static void Main(string[] args)
{
var factory = new ConnectionFactory() { HostName = "localhost" };
using(var connection = factory.CreateConnection())
using(var channel = connection.CreateModel())
{
channel.ExchangeDeclare(exchange: "direct_logs",
type: "direct");
var queueName = channel.QueueDeclare().QueueName; if(args.Length < )
{
Console.Error.WriteLine("Usage: {0} [info] [warning] [error]",
Environment.GetCommandLineArgs()[]);
Console.WriteLine(" Press [enter] to exit.");
Console.ReadLine();
Environment.ExitCode = ;
return;
} //同时绑定多个指定的routekey
foreach(var severity in args)
{
channel.QueueBind(queue: queueName,
exchange: "direct_logs",
routingKey: severity);
} Console.WriteLine(" [*] Waiting for messages."); var consumer = new EventingBasicConsumer(channel);
consumer.Received += (model, ea) =>
{
var body = ea.Body;
var message = Encoding.UTF8.GetString(body);
var routingKey = ea.RoutingKey;
Console.WriteLine(" [x] Received '{0}':'{1}'",
routingKey, message);
};
channel.BasicConsume(queue: queueName,
noAck: true,
consumer: consumer); Console.WriteLine(" Press [enter] to exit.");
Console.ReadLine();
}
}
}
2、Publish/Subscribe - Exchange类型fanout
这个类型忽略Routingkey，他为广播模式。
广播式时，Publish可以不指定queue和routekey。
using System;
using RabbitMQ.Client;
using System.Text; class EmitLog
{
public static void Main(string[] args)
{
var factory = new ConnectionFactory() { HostName = "localhost" };
using(var connection = factory.CreateConnection())
using(var channel = connection.CreateModel())
{
channel.ExchangeDeclare(exchange: "logs", type: "fanout"); var message = GetMessage(args);
var body = Encoding.UTF8.GetBytes(message);
channel.BasicPublish(exchange: "logs",
routingKey: "",
basicProperties: null,
body: body);
Console.WriteLine(" [x] Sent {0}", message);
} Console.WriteLine(" Press [enter] to exit.");
Console.ReadLine();
} private static string GetMessage(string[] args)
{
return ((args.Length > )
? string.Join(" ", args)
: "info: Hello World!");
}
}
subscribe可以只用临时队列接收
using System;
using RabbitMQ.Client;
using RabbitMQ.Client.Events;
using System.Text; class ReceiveLogs
{
public static void Main()
{
var factory = new ConnectionFactory() { HostName = "localhost" };
using(var connection = factory.CreateConnection())
using(var channel = connection.CreateModel())
{
channel.ExchangeDeclare(exchange: "logs", type: "fanout"); //这里生成了一个随机队列（string queue = "", bool durable = false, bool exclusive = true, bool autoDelete = true）
//In the .NET client, when we supply no parameters to queueDeclare() we create a non-durable, exclusive,
//autodelete queue with a generated name:
var queueName = channel.QueueDeclare().QueueName;
channel.QueueBind(queue: queueName,
exchange: "logs",
routingKey: ""); Console.WriteLine(" [*] Waiting for logs."); var consumer = new EventingBasicConsumer(channel);
consumer.Received += (model, ea) =>
{
var body = ea.Body;
var message = Encoding.UTF8.GetString(body);
Console.WriteLine(" [x] {0}", message);
};
channel.BasicConsume(queue: queueName,
noAck: true,
consumer: consumer); Console.WriteLine(" Press [enter] to exit.");
Console.ReadLine();
}
}
}
有一种简写的方式，用Subscription类
/// <summary>
/// 获取消息并处理
/// </summary>
/// <param name="queueName">队列名称</param>
/// <param name="action">接收到消息后的Action</param>
public void Receive(string queueName, Action<byte[]> action, bool multThread = true)
{
ConnectionFactory cf = new ConnectionFactory();
cf.UserName = this.UserName;
cf.Password = this.PassWord;
cf.HostName = this.HostName;
cf.Port = this.Port;
cf.VirtualHost = this.VitualHost; using (IConnection conn = cf.CreateConnection())
{
using (IModel ch = conn.CreateModel())
{
//声明交换器
ch.ExchangeDeclare(exchange: "e_linke1", type: "direct",durable: false);
ch.QueueDeclare(queue: queueName,
durable: false,
exclusive: false,
autoDelete: false,
arguments: null); //将队列绑定到交换器上
ch.QueueBind(queue: queueName,
exchange: "e_linke1",
routingKey: "elk");
using (Subscription sub = new Subscription(ch, queueName, true))
{
foreach (BasicDeliverEventArgs e in sub)
{
// handle the message contained in e ...
// ... and finally acknowledge it
if (multThread)
{
System.Threading.Tasks.Task.Factory.StartNew(() => { action(e.Body); });
}
else
{
action(e.Body);
} sub.Ack(e);
}
}
}
}
}
注：
如果有两个接收程序都是用了同一个的queue和相同的routingKey去绑定direct exchange的话，分发的行为是负载均衡的，也就是说第一个是程序1收到，第二个是程序2收到，以此类推。
如果有两个接收程序用了各自的queue，但使用相同的routingKey去绑定direct exchange的话，分发的行为是复制的，也就是说每个程序都会收到这个消息的副本。行为相当于fanout类型的exchange。
3、Exchange类型topic
这个类型的路由规则如果你掌握啦，那是相当的好用，与灵活。他是根据RoutingKey的设置，来做匹配的，其中这里还有两个通配符为：
*，代表任意的一个词。例如topic.zlh.*，他能够匹配到，topic.zlh.one ,topic.zlh.two ,topic.zlh.abc, ....
#，代表任意多个词。例如topic.#，他能够匹配到，topic.zlh.one ,topic.zlh.two ,topic.zlh.abc, ....
4、Headers Exchange
Headers类型的exchange使用的比较少，它也是忽略routingKey的一种路由方式。是使用Headers来匹配的。Headers是一个键值对，可以定义成Hashtable。发送者在发送的时候定义一些键值对，接收者也可以再绑定时候传入一些键值对，两者匹配的话，则对应的队列就可以收到消息。匹配有两种方式all和any。这两种方式是在接收端必须要用键值"x-mactch"来定义。all代表定义的多个键值对都要满足，而any则代码只要满足一个就可以了。之前的几种exchange的routingKey都需要要字符串形式的，而headers exchange则没有这个要求，因为键值对的值可以是任何类型。代码示例如下：
发送端:
channel.ExchangeDeclare("X1", "headers");
IBasicProperties properties = channel.CreateBasicProperties();
properties.Headers = new Hashtable();
properties.Headers.Add("Key1", );
properties.Headers.Add("Key2", );
XmlSerializer xs = new XmlSerializer(typeof(RequestMessage));
MemoryStream ms = new MemoryStream();
xs.Serialize(ms, message);
byte[] bytes = ms.ToArray();
channel.BasicPublish("X1", "", properties, bytes);接收端:
channel.ExchangeDeclare("X1", "headers");
//随机创建一个队列
string queue_name = channel.QueueDeclare("headerssubscriber2", true, false, false, null);
//绑定
IDictionary ht = new Hashtable();
ht.Add("x-match", "any");
ht.Add("Key1", );
ht.Add("Key2", );
channel.QueueBind(queue_name, "X1", "", ht);
//定义这个队列的消费者
QueueingBasicConsumer consumer = new QueueingBasicConsumer(channel);
channel.BasicConsume(queue_name, true, consumer);
while (true)
{
BasicDeliverEventArgs ea =
(BasicDeliverEventArgs)consumer.Queue.Dequeue();
byte[] bytes = ea.Body;
XmlSerializer xs = new XmlSerializer(typeof(RequestMessage));
using (MemoryStream ms = new MemoryStream(bytes))
{
RequestMessage message = (RequestMessage)xs.Deserialize(ms);
Console.WriteLine("Receive a Message, Id:" + message.MessageId + " Message:" + message.Message);
}
}3.RPC远程调用
参考链接:
.Net下RabbitMQ的使用(4) -- 订阅和发布 *
.Net下RabbitMQ的使用(7) -- 消息的传输控制 *
RabbitMQ Tutorials [官网]