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我正在使用 RabbitMQ 和 Node.JS 开发一个消息传递应用程序。我为此目的使用 amqplib。我是 Node.JS 的新手，在理解 amqplib 的语法方面发现了一些困难。例如，有一个用于声明队列的函数，即

channel.assertQueue([queue, [options, [function(err, ok) {...}]]]);

我从过去 2-3 天开始一​​直在提到这个，但我仍然不清楚这些 ->err和ok. 如何使用这些参数？

一个例子将不胜感激。

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1 回答 1

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ampqlib github 页面有一些关于如何使用库的示例，使用回调或承诺。

我复制了他们的第一个示例并添加了一些评论来解释正在发生的事情。

可能也值得检查他们的教程示例，这些示例遵循官方RabbitMQ 教程。

var amqp = require('amqplib/callback_api');
var q = 'tasks';

// connects to rabbitmq
amqp.connect('amqp://localhost', function(err, conn) {
    // this function will be called when the connection is created
    // `err` will contain the error object, if any errors occurred
    // `conn` will contain the connection object

    if (err != null) bail(err); // calls `bail` function if an error occurred when connecting
    consumer(conn); // creates a consumer
    publisher(conn); // creates a publisher
});

function bail(err) {
    console.error(err);
    process.exit(1);
}

// Publisher
function publisher(conn) {
    conn.createChannel(on_open); // creates a channel and call `on_open` when done
    function on_open(err, ch) {
        // this function will be called when the channel is created
        // `err` will contain the error object, if any errors occurred
        // `ch` will contain the channel object

        if (err != null) bail(err); // calls `bail` function if an error occurred when creating the channel
        ch.assertQueue(q); // asserts the queue exists
        ch.sendToQueue(q, new Buffer('something to do')); // sends a message to the queue
    }
}

// Consumer
function consumer(conn) {
    var ok = conn.createChannel(on_open); // creates a channel and call `on_open` when done
    function on_open(err, ch) {
        // this function will be called when the channel is created
        // `err` will contain the error object, if any errors occurred
        // `ch` will contain the channel object

        if (err != null) bail(err); // calls `bail` function if an error occurred when creating the channel
        ch.assertQueue(q); // asserts the queue exists
        ch.consume(q, function(msg) { //consumes the queue
            if (msg !== null) {
                console.log(msg.content.toString()); // writes the received message to the console
                ch.ack(msg); // acknowledge that the message was received
            }
        });
    }
}
于 2015-05-22T13:43:40.133 回答