Egg.js Basic Tutorial

官网：https://eggjs.org/zh-cn/

安装

// 1、创建并进入项目目录
mkdir egg-example && cd egg-example
// 2、初始化
npm init egg --type=simple
// 3、安装项目
npm i
// 4、启动项目
npm run dev
// http://localhost:7001

type的类型

simple - 基础应用模板

microservice - 基于egg的微服务模板

sequelize - 带有sequelize的egg应用

ts - typescript的基础应用模板

empty - 空模板

plugin - egg 插件模板

framework - 框架模板

核心功能

1、控制器 Controller

// app/controller/home.js
const Controller = require('egg').Controller;

class HomeController extends Controller {
  async index() {
    this.ctx.body = 'Hello world';
  }
}

module.exports = HomeController;

2、路由 Router

// app/router.js
module.exports = app => {
  const { router, controller } = app;
  router.get('/', controller.home.index);
};

3、服务 service

// app/service/news.js
const Service = require('egg').Service;

class NewsService extends Service {
  async list(page = 1) {
    // read config
    const { serverUrl, pageSize } = this.config.news;

    // use build-in http client to GET hacker-news api
    const { data: idList } = await this.ctx.curl(`${serverUrl}/topstories.json`, {
      data: {
        orderBy: '"$key"',
        startAt: `"${pageSize * (page - 1)}"`,
        endAt: `"${pageSize * page - 1}"`,
      },
      dataType: 'json',
    });

    // parallel GET detail
    const newsList = await Promise.all(
      Object.keys(idList).map(key => {
        const url = `${serverUrl}/item/${idList[key]}.json`;
        return this.ctx.curl(url, { dataType: 'json' });
      })
    );
    return newsList.map(res => res.data);
  }
}

module.exports = NewsService;

4、模板渲染 view

需要单独安装视图插件，比如egg-view-nunjucks等

5、配置文件

// config/config.default.js
exports.keys = <此处改为你自己的 Cookie 安全字符串>;

6、静态资源

app/public
├── css
│   └── news.css
└── js
    ├── lib.js
    └── news.js

7、 编写扩展

// app/extend/helper.js
const moment = require('moment');
exports.relativeTime = time => moment(new Date(time * 1000)).fromNow();

8、编写 Middleware

// app/middleware/robot.js
// options === app.config.robot
module.exports = (options, app) => {
  return async function robotMiddleware(ctx, next) {
    const source = ctx.get('user-agent') || '';
    const match = options.ua.some(ua => ua.test(source));
    if (match) {
      ctx.status = 403;
      ctx.message = 'Go away, robot.';
    } else {
      await next();
    }
  }
};

// config/config.default.js
// add middleware robot
exports.middleware = [
  'robot'
];
// robot's configurations
exports.robot = {
  ua: [
    /Baiduspider/i,
  ]
};

9、单元测试

// test/app/middleware/robot.test.js
const { app, mock, assert } = require('egg-mock/bootstrap');

describe('test/app/middleware/robot.test.js', () => {
  it('should block robot', () => {
    return app.httpRequest()
      .get('/')
      .set('User-Agent', "Baiduspider")
      .expect(403);
  });
});