七、通过主题进行消息分发

Topic Exchange

对于 routing_key 而言，有两个特殊字符：

• *：代表任意单词
• #：代表0个或多个单词

Topic Exchange 与其他 Exchange 的转化：

• routing_key 是 #，会接收所有 Message，此时等同于 Fanout Exchange；
• routing_key 不包含 # 或 *，则等同于 Direct Exchange

代码实现

emit_logs_topic.php

<?php
/**
 * 发送消息
 */

$exchangeName = 'topic_logs';
$topic = empty($argv[1]) ? 'anonymous.info' : $argv[1]; // 主题
$message = empty($argv[2]) ? 'Hello World!' : $argv[2];

// 建立TCP连接
$connection = new AMQPConnection([
    'host' => 'localhost',
    'port' => '5672',
    'vhost' => '/',
    'login' => 'guest',
    'password' => 'guest'
]);
$connection->connect() or die("Cannot connect to broker!\n");

$channel = new AMQPChannel($connection);
$exchange = new AMQPExchange($channel);
$exchange->setName($exchangeName);
$exchange->setType(AMQP_EX_TYPE_TOPIC);
$exchange->declareExchange();

$exchange->publish($message, $topic);
echo "Message is sent: " . $message . "\n";
$connection->disconnect();

receive_logs_topic.php

<?php
/**
 * 接收消息
 */

$exchangeName = 'topic_logs';
$topic = $argv[1];

// 建立TCP连接
$connection = new AMQPConnection([
    'host' => 'localhost',
    'port' => '5672',
    'vhost' => '/',
    'login' => 'guest',
    'password' => 'guest'
]);
$connection->connect() or die("Cannot connect to broker!\n");

$channel = new AMQPChannel($connection);

$exchange = new AMQPExchange($channel);
$exchange->setName($exchangeName);
$exchange->setType(AMQP_EX_TYPE_TOPIC);
$exchange->declareExchange();

$queue = new AMQPQueue($channel);
$queue->setFlags(AMQP_EXCLUSIVE);
$queue->declareQueue();
$queue->bind($exchangeName, $topic);

echo "Waiting for logs...\n";
while (TRUE) {
    $queue->consume('processLogs');
}

$connection->disconnect();

function processLogs($envelope, $queue) {
    $logs = $envelope->getBody();
    var_dump("Received: " . $logs);
    $queue->ack($envelope->getDeliveryTag()); // 手动发送ACK应答
}

运行代码：