Javascript 如何使用lib amqp.node中的方法consume获取所有消息?
问候各位。Javascript 如何使用lib amqp.node中的方法consume获取所有消息?,javascript,node.js,async-await,rabbitmq,node-amqp,Javascript,Node.js,Async Await,Rabbitmq,Node Amqp,问候各位。 你能帮我处理node.js中的异步吗 此问题: 我使用这里那里的方法consume,他从RabbitMQ发送消息,但该方法首先返回关于他开始的承诺,在这个承诺开始后,他调用回调从RabbitMQ获取数据,我不知道如何捕获何时所有消息都将发送到我的node js应用程序 如需更多解释,请参阅我的代码,并在注释的结尾处填写我想要的代码: /** * Here my test code * * requirng amqp.node lib */ let amqp = require
你能帮我处理node.js中的异步吗 此问题: 我使用这里那里的方法consume,他从RabbitMQ发送消息,但该方法首先返回关于他开始的承诺,在这个承诺开始后,他调用回调从RabbitMQ获取数据,我不知道如何捕获何时所有消息都将发送到我的node js应用程序 如需更多解释,请参阅我的代码,并在注释的结尾处填写我想要的代码:
/**
* Here my test code
*
* requirng amqp.node lib
*/
let amqp = require('amqplib')
, configConnection = { /* ..config options */ }
, queue = 'users'
, exchange = 'users.exchange'
, type = 'fanout'
/**
* declare annonymous function as async and immediately called it
*/
(async () => {
/**
* declare connection and channel with using async/await construction
* who support version node.js >= 8.5.0
*/
let conn = await amqp.connect(configConnection)
let channel = await conn.createChannel()
await channel.assertExchange(exchange, type)
let response = await channel.assertQueue(queue)
/**
* response: { queue: 'users', messageCount: 10, consumerCount: 0 }
*/
response = await channel.bindQueue(response.queue, exchange, '')
response = await channel.consume(response.queue, logMessage, {noAck: false})
/**
* {noAck: false} false for not expect an acknowledgement
*/
console.log('reading for query finish')
function logMessage(msg) {
console.log("[*] recieved: '%s'", msg.content.toString())
}
})()
/**
* output will show:
* reading for query finish
* [*] recieved: 'message content'
* [*] recieved: 'message content'
* [*] recieved: 'message content'
* ...
*
* But i'm need show message 'reading for query finish' after when
* all consumes will executed
*
* Ask: How i can do this?
*/
我找到了我问题的答案 正在使用的答案:EventEmitter&&Promise 魔法(对我来说)就在这里:
等待新承诺(resolve=>eventEmitter.once('consumerdone',resolve))
最后的代码是:
/**
* Here my test code
*
* requirng amqp.node lib
*/
let amqp = require('amqplib')
, EventEmitter = require('events')
, eventEmitter = new EventEmitter()
, timeout = 10000
, configConnection = { /* ..config options */ }
, queue = 'users'
, exchange = 'users.exchange'
, type = 'fanout'
/**
* declare annonymous function as async and immediately called it
*/
(async () => {
/**
* declare connection and channel with using async/await construction
* who support version node.js >= 8.5.0
*/
let conn = await amqp.connect(configConnection)
let channel = await conn.createChannel()
await channel.assertExchange(exchange, type)
let response = await channel.assertQueue(queue)
/**
* response: { queue: 'users', messageCount: 10, consumerCount: 0 }
*/
let messageCount = response.messageCount
response = await channel.bindQueue(response.queue, exchange, '')
response = await channel.consume(response.queue, logMessage(messageCount), {noAck: false})
/**
* {noAck: false} false for not expect an acknowledgement
*/
/**
* declare timeout if we have problems with emit event in consume
* we waiting when event will be emit once 'consumeDone' and promise gain resolve
* so we can go to the next step
*/
setTimeout(() => eventEmitter.emit('consumeDone'), timeout)
await new Promise(resolve => eventEmitter.once('consumeDone', resolve))
console.log('reading for query finish')
function logMessage(messageCount) {
return msg => {
console.log("[*] recieved: '%s'", msg.content.toString())
if (messageCount == msg.fields.deliveryTag) {
eventEmitter.emit('consumeDone')
}
}
}
})()
请尝试以下代码:
let amqp = require('amqplib/callback_api');
function init() {
let configConnection = {
protocol: 'amqp',
hostname: 'localhost',
port: 5672,
username: 'root',
password: '1111',
heartbeat: 60,
};
let messageCount = 0;
let messageCounter = 0;
let queue_name = 'queue_name';
let messages = [];
amqp.connect(configConnection, function (error, connect) {
if (error) {
throw error;
}
// Create channel and get info about queue
connect.createChannel(function (error1, channel) {
if (error1) {
throw error1;
}
channel.assertQueue(queue_name, {durable: true}, (error2, result) => {
// here you get count of messages
messageCount = result.messageCount;
// Consume to queue
channel.consume(queue_name, function (msg) {
msg = msg.content.toString();
messages.push(msg);
// Show all messages and exit
if (messageCount === ++messageCounter) {
console.log(messages);
process.exit();
}
}, {
noAck: true
});
});
});
});
}
init();
请解释一下你的代码是做什么的,以及你是如何解决这个问题的。首先,您可以assertQueue并获取队列2中所有消息的计数。具有消息和已获取消息总数的生成逻辑