RabbitMQ 实验消费原始队列消息，拒绝（reject）投递死信交换机过程

如果你想通过 RabbitMQ 的死信队列功能实现消费者拒绝消息投递到死信交换机的行为，你可以按照以下步骤操作：

创建原始队列，并将其绑定到一个交换机上：

export RABBITMQ_SERVER=127.0.0.1
export RABBITMQ_PORT=5672   
export RABBITMQ_USER=mingcai     
export RABBITMQ_PASSWORD=passwordrabbitmqadmin list exchanges
rabbitmqadmin declare queue name=my_queue durable=true
rabbitmqadmin declare exchange name=my_exchange type=direct
rabbitmqadmin declare binding source=my_exchange destination=my_queue routing_key=my_routing_key

创建死信交换机和死信队列，并将死信队列绑定到死信交换机：

rabbitmqadmin declare exchange name=my_dlx type=direct
rabbitmqadmin declare queue name=my_dlq durable=true
rabbitmqadmin declare binding source=my_dlx destination=my_dlq routing_key=dlx_routing_key

设置原始队列的参数，包括死信交换机和死信路由键：

rabbitmqadmin declare queue name=my_queue durable=true arguments='{"x-dead-letter-exchange":"my_dlx", "x-dead-letter-routing-key":"dlx_routing_key"}'

编写消费者代码，在消费者代码中拒绝投递消息到死信交换机：

//Consumer.ts
import * as amqp from 'amqplib';async function main() {const connection = await amqp.connect('amqp://mingcai:password@127.0.0.1');const channel = await connection.createChannel();const queue = 'my_queue';await channel.consume(queue, async (msg) => {if (msg !== null) {try {await new Promise(resolve => {setTimeout(()=>{resolve(true)},3000)})// Process the messageconsole.log("Received message:", msg.content.toString());// Simulate rejection of message delivery to dead letter exchangethrow new Error("Failed to process message, rejecting delivery to dead letter exchange");} catch (error) {// Reject the message delivery to dead letter exchangechannel.reject(msg, false);console.error("Error processing message:", error.message);}}});console.log('Waiting for messages...');
}main().catch(console.error);

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在这个示例中，当消费者处理消息时发生错误时，它会将消息的投递拒绝到死信交换机。这样，这些被拒绝的消息将被重新路由到死信队列 my_dlq 中。

记得根据你的具体需求修改队列、交换机和消费者的配置，确保它们符合你的预期行为。

rabbitmqadmin purge queue name=my_dlq #删除队列中的所有消息


//Producer.ts 
import * as amqp from 'amqplib';async function sendMsg() {try {const connection = await amqp.connect('amqp://mingcai:password@127.0.0.1');const channel = await connection.createChannel(); // 创建通道const delayQueue = 'my_queue'; // 延迟队列名称// 每秒发送一条消息for (let i = 0; i < 100; i++) {await new Promise(resolve => {setTimeout(() => {resolve(true)}, 1000)})const message = 'Hello RabbitMQ!';channel.sendToQueue(delayQueue, Buffer.from(message));console.log('消息已发送:', message);}} catch (error) {console.error('错误:', error);}
}sendMsg()