AsyncAPI 提供了类似openapi的代码生成，以下demo，来自官方，只是目前官方的generator有些问题以下
同时说明运行中的一些问题
环境准备
主要是安装依赖组件
npm install -g asyncapi-generator mqtt
定义AsyncAPI
稍有改动，主要是channel（mqtt 的topic）
- yaml 文件
asyncapi: ‘2.0.0‘
info:
title: Streetlights API
version: ‘1.0.0‘
description: |
The Smartylighting Streetlights API allows you
to remotely manage the city lights.
license:
name: Apache 2.0
url: ‘https://www.apache.org/licenses/LICENSE-2.0‘
?
servers:
mosquitto:
url: test.mosquitto.org
protocol: mqtt
?
channels:
dalong/measured:
publish:
summary: Inform about environmental lighting conditions for a particular streetlight.
message:
payload:
type: object
properties:
id:
type: integer
minimum: 0
description: Id of the streetlight.
lumens:
type: integer
minimum: 0
description: Light intensity measured in lumens.
sentAt:
type: string
format: date-time
description: Date and time when the message was sent.
?
- 生成代码命令
ag asyncapi.yaml nodejs -p server=mosquitto
- 简单说明
如果直接使用url test.mosquitto.org 会有解析的问题，如下：
Something went wrong:
Template render error: (unknown path) [Line 29, Column 36]
TypeError [ERR_INVALID_URL]: Invalid URL: test.mosquitto.org
at Object._prettifyError (/usr/local/lib/node_modules/asyncapi-generator/node_modules/nunjucks/src/lib.js:36:11)
at /usr/local/lib/node_modules/asyncapi-generator/node_modules/nunjucks/src/environment.js:567:19
at Template.root [as rootRenderFunc] (eval at _compile (/usr/local/lib/node_modules/asyncapi-generator/node_modules/nunjucks/src/environmen
t.js:637:18), <anonymous>:83:3)
at Template.render (/usr/local/lib/node_modules/asyncapi-generator/node_modules/nunjucks/src/environment.js:556:10)
at Environment.renderString (/usr/local/lib/node_modules/asyncapi-generator/node_modules/nunjucks/src/environment.js:380:17)
at Promise (/usr/local/lib/node_modules/asyncapi-generator/lib/generator.js:507:21)
at new Promise (<anonymous>)
at Generator.renderString (/usr/local/lib/node_modules/asyncapi-generator/lib/generator.js:506:12)
at Generator.renderFile (/usr/local/lib/node_modules/asyncapi-generator/lib/generator.js:531:19)
at <anonymous>
解决方法：临时修改为一个url 格式的比如test.mosquitto.org:1883 生成代码之后再修改回来
- 生成效果
Done! ?
Check out your shiny new generated files at /Users/dalong/mylearning/asyncapi-learning/first/streetlights.
- 修改几处生成的代码
配置文件：
config/common.yml:
如下：
default:
app:
name: Streetlights API
version: 1.0.0
?
broker:
mqtt:
url: mqtt://test.mosquitto.org
topics: ["dalong/measured"]
qos:
protocol: mqtt
retain:
subscribe: true
?
development:
?
test:
?
staging:
?
production:
?
路由以及handler修改：
路由：
随便些一个名字，注意后边handler 需要和这个一样
启动&&测试
- 安装npm依赖
yarn
- 启动
yarn start
- 模拟消息发送
mqtt pub -t ‘dalong/measured‘ -h ‘test.mosquitto.org‘ -m ‘{"id": 1111, "lumens": 3, "sentAt": "2019-10-06T12:34:32.000Z"}‘
- 效果
说明
以上是一个简单的试用，以及在使用中碰到的问题，AsyncAPI 是一个很不错的编写事件驱动应用的指南
参考资料
https://www.asyncapi.com/docs/tutorials/streetlights/
https://github.com/asyncapi/generator
http://test.mosquitto.org/
https://github.com/rongfengliang/asyncapi-streetlights-demo