AsyncAPI 是一种用于描述异步 API 的规范,RabbitMQ 是一种基于 AMQP 协议的消息队列。下面的示例演示了如何使用 AsyncAPI 定义一个基于 RabbitMQ 的异步 API。
首先,在 AsyncAPI 规范 YAML 文件中定义 Exchange 和 Queue。以下是一个例子:
asyncapi: '2.0.0'
info:
title: My API
version: '1.0.0'
channels:
user.signup:
publish:
$ref: '#/components/messages/UserSignUpEvent'
subscribe:
$ref: '#/components/messages/UserSignUpEvent'
components:
messages:
UserSignUpEvent:
name: UserSignUpEvent
payload:
$ref: './schemas/UserSignUpEvent.yaml'
schemas:
UserSignUpEvent.yaml:
type: object
properties:
username:
type: string
email:
type: string
在上面的示例中,我们定义了一个名为 user.signup 的通道,并在其中定义了一个名为 UserSignUpEvent 的消息。这个消息具有 username 和 email 两个属性。
接下来,在代码中使用 AMQP 和 AsyncAPI 库来实现 RabbitMQ 和 AsyncAPI 的交互。以下是一个例子:
const amqp = require('amqplib')
const { AsyncAPI } = require('@asyncapi/parser')
async function main() {
const asyncapi = await AsyncAPI
.fromFile('asyncapi.yml')
.catch(error => {
console.error(`There was an error parsing the AsyncAPI definition: ${error}`)
process.exit(1)
})
const channelName = 'user.signup'
const { publish, subscribe } = asyncapi.getChannel(channelName)
const connection = await amqp.connect('amqp://localhost')
const channel = await connection.createChannel()
const exchangeName = publish.binding.amqp.exchange.name
const queueName = subscribe.binding.amqp.queue.name
await channel.assertExchange(exchangeName, 'fanout', { durable: false })
await channel.assertQueue(queueName, { exclusive: true })
await channel.bindQueue(queueName, exchangeName, '')
channel.consume(queueName, (message) => {
console.log(`Received message: ${message.content}`)
})
const message = { username: 'johndoe', email: 'johndoe@example.com' }
const payload = JSON.stringify(message)
channel.publish(exchangeName, '', Buffer.from(payload))
console.log(`Sent message: ${payload}`)
}
main()
在上面的代码中,我们首先使用 Async