# Egg - Build a commercial egg.js framework from scratch

In this article, you can learn:

Generate a Swagger-UI document in the egg

Create a project

Egg. Js official document portal

Install dependencies:

$ mkdir egg-example && cd egg-example
$ npm init egg --type=simple // Create the project using the official scaffolding (simple: standard template)
$ npm i
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Start the project

$ npm run dev
$ open http://localhost:7001
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Integrate Swagger-UI documentation

Install dependencies

npm install egg-swagger-doc-feat -S
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Declare plug-ins in config/plugin.js

/ * *@type Egg.EggPlugin */
module.exports = {
  swaggerdoc: {
    enable: true.package: 'egg-swagger-doc-feat',}};Copy the code

Config /config.default.js file to configure the SwaggerDoc plug-in

'use strict';
module.exports = appInfo= > {
  const config = (exports = {});
  config.keys = appInfo.name + '_1622015186058_5727';

  // add your middleware config here
  config.middleware = [];

  // add your user config here
  const userConfig = {
    // Configure swagger- UI interface document
    swaggerdoc: {
      dirScanner: './app/controller'.// Specify the directory where swaggerDoc is retrieved,
      apiInfo: {
        title: 'XXX project interface'.description: 'SWAGger - UI for egg'.version: '1.0.0',},// The main information, description, and version number of the interface document
      schemes: ['http'.'https']./ / agreement
      consumes: ['application/json'].// Output mode
      produces: ['application/json'].enableSecurity: false.//enableValidate:true,// whether to enable parameter validation.
      routerMap: true.// Whether to automatically register routes (very fragrant)
      enable: true,}};return{... config, ... userConfig, }; };Copy the code

Write jSDoc for an interface

Example: inapp/controller/home.jsIn the file

const Controller = require ('egg').Controller;
/ * * *@Controller Home page * /
class HomeController extends Controller {
  / * * *@summary Home page *@description Get home page data *@router get /api/home/index
   * @request body indexRequest *body
   * @response 200 baseResponse request succeeded */
  async index () {
    const {ctx} = this;
    ctx.body = 'hi, egg'; }}module.exports = HomeController;
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The restriction on the return value of the interface is configured

}}}}}}}}}}}}}}}}}}}}}}}}

newapp/contract/index.jsFile (do not write the contract name wrong, this is the default folder to read model)

module.exports = {
 baseRequest: {},
 baseResponse: {//@response 200 baseResponse Operation result. The name corresponds to the corresponding result
   code: {type: 'integer'.required: true.example: 0},
   data: {
     type: 'string'.example: 'Request successful',},errorMessage: {type: 'string'.example: 'Request successful',}}};Copy the code

newapp/contract/home.jsfile

module.exports = {
  indexRequest: {
    test: {type: 'string'.require: true.description: 'test',}}};Copy the code

Visit http://127.0.0.1:7002/swagger-ui.html (my project is 7002, generally the default is 7001)

Integrated exception capture system

For a mature system, an exception catching system is necessary,

This can be considered in two ways:

Some errors in the production environment can not be thrown to the user, easy to cause system security problems

The onion ring model can be used to make a global exception catching middleware

write

The new app/middleware/error_handler. Js

module.exports = (options, app) = > {
  return async (ctx, next) => {
    try {
      await next ();
    } catch (err) {
      ctx.app.emit ('error', err, ctx);

      const status = err.status || 500;
      // The detailed error contents of the 500 error in the production environment are not returned to the client because they may contain sensitive information
      const error = status === 500 && ctx.app.config.env === 'prod'
        ? 'Internal Server Error'
        : err.message;

      // Read each property from the error object and set it in the response
      ctx.body = {error};
      if (status === 422) {//422 is a parameter validation type errorctx.body.detail = err.errors; } ctx.status = status; }}; };Copy the code

Mount the global middleware in config/config.default.js

'use strict';
module.exports = appInfo= > {
  const config = (exports = {});
  config.keys = appInfo.name + '_1622015186058_5727';

  // Mount the application-level middleware
  config.middleware = ["errorHandler"];

  // Add the user-defined configuration
  const userConfig = {
    // Configure swagger- UI interface document
    swaggerdoc: {
      dirScanner: './app/controller'.// Specify the directory where swaggerDoc is retrieved,
      apiInfo: {
        title: 'XXX project interface'.description: 'SWAGger - UI for egg'.version: '1.0.0',},// The main information, description, and version number of the interface document
      schemes: ['http'.'https']./ / agreement
      consumes: ['application/json'].// Output mode
      produces: ['application/json'].enableSecurity: false.routerMap: true.// Whether to automatically register routes (very fragrant)
      enable: true,}};return{... config, ... userConfig, }; };Copy the code

validation

Modify the app/controller/home.js file to actively throw an error and validate our errorHandler middleware.

const Controller = require ('egg').Controller;
/ * * *@Controller Home page * /
class HomeController extends Controller {
  / * * *@summary Home page *@description Get home page data *@router get /api/home/index
   * @request body indexRequest *niji
   * @response 200 baseResponse request succeeded */
  async index () {
    const {ctx} = this;
    aaaaaaaaaaaaaaaaaaaaaaa ();// This method does not exist
    ctx.body = 'hi, egg'; }}module.exports = HomeController;
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Access this interface, success!

Integrate structured return data

When we write an interface that returns data, the structure of the data must always be the same. We can write:

ctx.body = {name:"xxx",age:34}
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But it would be annoying to write every function like this, and we need a uniform way to do it:

Create the app/extend/helper.js file

exports.success = ({ctx, res, code, message}) = > {
  ctx.body = {
    code: code || 100.data: res,
    message: message || 'Request successful'}; ctx.status =200;
};

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In the app/controller/home.js file, use the HelperAPI

const Controller = require ('egg').Controller;
/ * * *@Controller Home page * /
class HomeController extends Controller {
  / * * *@summary Home page *@description Get home page data *@router get /api/home/index
   * @request body indexRequest *niji
   * @response 200 baseResponse request succeeded */
  async index () {
    const {ctx} = this;
    ctx.helper.success ({ctx, res: {value: 1}, message: 'Request successful'}); }}module.exports = HomeController;
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Request the interface and view the returned data

Integrated parameter verification function

Install dependencies

npm install egg-validate -S
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config/plugin.jsConfiguration in file

'use strict';

/ * *@type Egg.EggPlugin */
module.exports = {
  // had enabled by egg
  // static: {
  // enable: true,
  // }
  swaggerdoc: {
    enable: true.package: 'egg-swagger-doc-feat',},eggvalidaate: {
    enable: true.package: 'egg-validate',}};Copy the code

The first:`egg-validate`Normal use

We normally use egg-validate in the following way, because when you install egg-validate, the context object CTX will be mounted with the validate method when the application starts

In the app/controller/home.js file

const Controller = require ('egg').Controller;
/ * * *@Controller Home page * /
class HomeController extends Controller {
  / * * *@summary Home page *@description Get home page data *@router get /api/home/index
   * @request body indexRequest *niji
   * @response 200 baseResponse request succeeded */
  async index () {
    const {ctx} = this;
    ctx.validate ({
      id: {type: 'number'.required: true},
      phoneNumber: {type: 'string'.requried: true.format: /^1[34578]\d{9}$/}}); ctx.helper.success ({ctx,res: {value: 1}, message: 'Request successful'}); }}module.exports = HomeController;
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Request the interface and test it

The second:`egg-validate`In combination with`egg-swagger-doc-feat`Configuration use of

When we use egg-validate normally, we need to pass a rule object to ctx.validate({}), which is annoying.

Validate ({}) = “ctx.validate({})”; (The configuration of the rule attribute of egg-validate is the same as that of egg-swagger-doc-feat.) In this way, we share the same rule, which is convenient for our later maintenance.

The NPM package, egg-Swagger -doc-feat, does not implement parameter verification (as mentioned in the configuration above), but it does mount all the rules defined in app/ Contract to the context object ctx.rule.

In this case, we can write our code like this:

In the app/controller/home.js file

const Controller = require ('egg').Controller;
/ * * *@Controller Home page * /
class HomeController extends Controller {
  / * * *@summary Home page *@description Get home page data *@router get /api/home/index
   * @request body indexRequest *niji
   * @response 200 baseResponse request succeeded */
  async index () {
    const {ctx} = this;
    ctx.validate (ctx.rule.indexRequest);
    ctx.helper.success ({ctx, res: {value: 1}, message: 'Request successful'}); }}module.exports = HomeController;
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Request the interface and test it

Perfect!!

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# Egg — Build a commercial egg.js framework from scratch

Create a project

Integrate Swagger-UI documentation

Integrated exception capture system

write

validation

Integrate structured return data

Integrated parameter verification function

The first:`egg-validate`Normal use

The second:`egg-validate`In combination with`egg-swagger-doc-feat`Configuration use of

# Egg — Build a commercial egg.js framework from scratch

Create a project

Integrate Swagger-UI documentation

Integrated exception capture system

write

validation

Integrate structured return data

Integrated parameter verification function

The first:egg-validateNormal use

The second:egg-validateIn combination withegg-swagger-doc-featConfiguration use of

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The first:`egg-validate`Normal use

The second:`egg-validate`In combination with`egg-swagger-doc-feat`Configuration use of