🪕 Request

• request.body

  app.use(express.json()); // for parsing `application/json`
  app.use(express.urlencoded({ extended: true })); // for parsing `application/x-www-form-urlencoded`

• originalUrl (=baseUrl+path)
• baseUrl
• path

🪕 Response

🪕 Router

• app.route()
• express.Router()

🪕 app.use + middleware

Usually we don’t want Node.js to directly serve a website. Things like SSL or TLS encryption are doable, but a web server was exactly made for such a task. That’s why the most common setup is running Express Apps behind some reverse proxy like Nginx.

🪕 handling warning/error

🪕 集成模块

• node-fetch
• require.js
• jwttoken
• cluster
• serve-favicon
• helmet: helps secure your app by setting various HTTP headers
• passport: authentication using “strategies” such as OAuth2, OpenID, and many others.
• compression (nginx, static files, e.g. images)

🪕 Node.js process crashing

• Always handle promise rejections. Listen to unhandled rejection events for crash reporting. And always use errors to reject promises in order to get stack traces!
• Always handle the error event for streams!
• Wrap JSON.parse() and any Sync() function in a try-catch block or inside a Promise. Well, in general any function that can throw errors.

Note that uncaughtException is a very crude mechanism for exception handling and may be removed in the future

🪕 DOMAIN with Cluster

🪕 process.env, .env

• process.env 和 require(‘dotenv’)没有必然关系。
• 如果从~/.bash_profile 中取环境变量，就不需要。
• 如果从.env 中取环境变量，就需要。

🪕 express mvc

🪕 more

• knex.js for creating data models
• websocket: express-ws
• reporting: tableau, charting tools
• schedule tasks: cron
• batch process:
• fs-extra, through2, fast-csv

⚡️File Management

There are times we just need to move a file, or remove it, or read the contents. I use the nativefs module, or the fs-extra module to perform these steps. I use through2 when I’m using streams to process large data sets and need to pipe structured data into another step. I’ll also use fast-csv to work with CSV files.

if (!fs.existsSync(dir)) {
	fs.mkdirSync(dir);
}

📑 Log.io

Logo.io是一个基于 NodeJS 开发的实时日志监控项目，在浏览器里访问。需要注意的是，Logo.io只监视日志变动并不存储日志，不过这个没关系，只要知道日志存储在哪个机器上。

Logo.io使用Socket.io库发送活动报告的，和其他的监控工具一样，Logo.io也采用服务器－客户端的模式。Logo.io由两部分组成：server和harveste，server运行在机器 A（服务器）上监视和纪录其他机器发来的日志消息；log harvester 运行在机器 B（客户端）上用来监听和收集机器 B 上的日志改动，并将改动发送给机器 A，每个需要纪录日志的机器都需要一个harvester。