Loopback 4 中间件未注册

Question

我在这里按照这个示例进行简单的日志记录中间件设置。但我似乎无法让它记录我的请求信息。当我点击 时，我得到了标准响应/ping，但没有任何内容被注销到控制台。

我尝试在两个不同的位置注册中间件。index.ts和application.ts。

// src/middleware/log.middleware.ts

import { Next } from '@loopback/core'
import { Middleware, MiddlewareContext } from '@loopback/rest'

export const testLoggingMiddleware: Middleware = async (
  middlewareCtx: MiddlewareContext,
  next: Next,
) => {
  const { request } = middlewareCtx
  console.log('Request: %s %s', request.method, request.originalUrl)
  try {
    // Proceed with next middleware
    await next()
    // Process response
    console.log('Response received for %s %s', request.method, request.originalUrl)
  } catch (err) {
    // Catch errors from downstream middleware
    console.error('Error received for %s %s', request.method, request.originalUrl)
    throw err
  }
}

// src/index.ts

import { ApplicationConfig, RemoteConfigurationsApplication } from './application'
import { testLoggingMiddleware } from './middleware/log.middleware'
import { NodeEnvironmentService } from './services'

export * from './application'

export async function main(
  options: ApplicationConfig = {},
): Promise<RemoteConfigurationsApplication> {
  const app = new RemoteConfigurationsApplication(options)

  app.middleware(testLoggingMiddleware) // trying to add the middleware here as well

  await app.boot()
  await app.start()

  const url = app.restServer.url
  console.log(`Server is running at ${url}`)
  console.log(`Try ${url}/ping`)

  return app
}

if (require.main === module) {
  // Run the application
  const config = {
    rest: {
      port: +(process.env.PORT ?? 8081),
      host: process.env.HOST,
      // The `gracePeriodForClose` provides a graceful close for http/https
      // servers with keep-alive clients. The default value is `Infinity`
      // (don't force-close). If you want to immediately destroy all sockets
      // upon stop, set its value to `0`.
      // See https://www.npmjs.com/package/stoppable
      gracePeriodForClose: 5000, // 5 seconds
      openApiSpec: {
        // useful when used with OpenAPI-to-GraphQL to locate your application
        setServersFromRequest: true,
      },
      basePath: `/`,
      cors: {
        origin: '*',
        methods: 'GET,HEAD,PUT,PATCH,POST,DELETE',
        preflightContinue: false,
        optionsSuccessStatus: 204,
        credentials: true,
      },
    },
  }
  main(config).catch((err) => {
    console.error('Cannot start the application.', err)
    process.exit(1)
  })
}

// src/application.ts

require('dotenv').config()

import { BootMixin } from '@loopback/boot'
import { ApplicationConfig } from '@loopback/core'
import { HealthComponent } from '@loopback/extension-health'
import { RestExplorerBindings, RestExplorerComponent } from '@loopback/rest-explorer'
import { RepositoryMixin } from '@loopback/repository'
import { RestApplication } from '@loopback/rest'
import { ServiceMixin } from '@loopback/service-proxy'
import * as path from 'path'
import { testLoggingMiddleware } from './middleware/log.middleware'
import { MySequence } from './sequence'

export { ApplicationConfig }

export class RemoteConfigurationsApplication extends BootMixin(
  ServiceMixin(RepositoryMixin(RestApplication)),
) {
  constructor(options: ApplicationConfig = {}) {
    super(options)

    // Set up the custom sequence
    this.sequence(MySequence)

    // Set up default home page
    this.static('/', path.join(__dirname, '../public'))

    // Customize @loopback/http-explorer configuration here
    this.configure(RestExplorerBindings.COMPONENT).to({
      path: '/explorer',
    })
    this.component(RestExplorerComponent)

    this.component(HealthComponent)

    this.middleware(testLoggingMiddleware) // adding middleware in application

    this.projectRoot = __dirname
    // Customize @loopback/boot Booter Conventions here
    this.bootOptions = {
      controllers: {
        // Customize ControllerBooter Conventions here
        dirs: ['controllers'],
        extensions: ['.controller.js'],
        nested: true,
      },
    }
  }
}

Answer 1

如果有人仍然遇到这个问题，这对我有用：

1. 更新您的sequence.ts，使其看起来像这样：

    import { MiddlewareSequence } from '@loopback/rest';
    
    export class MySequence extends MiddlewareSequence {}

2. 在 /src/middleware/example.middleware.ts 上创建中间件

import { Next } from '@loopback/core'
import { Middleware, MiddlewareContext } from '@loopback/rest'

export const exampleMiddleware: Middleware = async (
  middlewareCtx: MiddlewareContext,
  next: Next,
) => {
  const {request} = middlewareCtx
  console.log('Request: %s %s', request.headers, request.method, request.originalUrl)
  try {
    // Proceed with next middleware
    const result = await next()
    // Process response
    console.log('Response received for %s %s', request.method, request.originalUrl)
    return result
  } catch (err) {
    // Catch errors from downstream middleware
    console.error('Error received for %s %s', request.method, request.originalUrl)
    throw err
  }
}

3. 在 application.ts 中注册您的中间件

    import {ApplicationConfig} from '@loopback/core';
    import {RestApplication} from '@loopback/rest';
    import {exampleMiddleware} from './middleware/example.middleware';

    export class MyApplication extends RestApplication {
      constructor(config: ApplicationConfig) {
        // register your middleware
        this.middleware(exampleMiddleware);
      }
    }

4. 运行应用程序并检查您的控制台。

参考文档