如何在loopback 4.0中使用存储组件？

问题描述 投票：1回答：2

我正在使用loopback 3.0中的存储组件来访问云存储。但我需要如何在loopback 4.0中实现。以下链接使其在3.0中进行采样。

https://github.com/strongloop/loopback-example-storage

typescript loopback
2个回答
2
投票

来自LoopBack团队的您好！

我们还没有研究Loopback-component-storage与LoopBack版本4的集成。

由于存储组件的行为更像连接器而不是组件，我认为应该可以通过@loopback/service-proxy层在LoopBack 4中使用它。有关文档，请参阅Calling other APIS and web services。该页面上的代码片段以loopback-connector-rest为例，您将使用loopback-component-storage代替。

一旦您可以从JavaScript / TypeScript访问存储组件，您还需要公开REST API。 LoopBack 4不提供任何内置控制器，您必须自己编写一个。请参阅storage-service.js中LB3远程方法的定义，您需要构建控制器方法以接受相同的参数，然后调用引擎下的服务代理。

如果您愿意研究这种集成，那么最好在loopback-next中打开一个新的GitHub问题，在那里我们可以进行结构化对话。

1
投票

我将与社区分享我的实现，因为即使Miroslav Bajtoš的答案是做到这一点的关键，文档建议不是很清楚，我指的是Calling other APIS and web services。

  • 首先，我使用lb4命令cli工具创建一个新的DataSource，并使用与我在loopback 3数据源中使用的相同的密钥填充json文件。
// storage.datasource.ts

import { inject } from '@loopback/core';
import { juggler } from '@loopback/service-proxy';
import * as config from './storage-gc.datasource.json';


export class StorageGCDataSource extends juggler.DataSource {
  static dataSourceName = 'StorageGC';

  constructor(
    @inject('datasources.config.StorageGC', { optional: true })
    dsConfig: object = config,
  ) {
    super(dsConfig);
  }
}

// storage.datasource.json
{
  "name": "Storage",
  "connector": "loopback-component-storage",
  "provider": "google",
  "keyFilename": "your-project-key.json",
  "projectId": "your-project-id",
  "nameConflict": "makeUnique"
}
// Note: your-project-key.json is in the root folder at the same level that tsconfig.json

请记住，您需要安装loopback-component-storage运行

npm install --save loopback-component-storage

  • 第二，我使用lb4命令cli工具创建了两个新模型。这些模型是：Container和File。
// container.model.ts

import {Entity, model, property} from '@loopback/repository';

@model()
export class Container extends Entity {
  @property({
    type: 'string',
    required: true,
  })
  name: string;


  constructor(data?: Partial<Container>) {
    super(data);
  }
}


// file.model.ts

import { Entity, model, property } from '@loopback/repository';

@model()
export class File extends Entity {
  @property({
    type: 'string',
    required: true,
  })
  name: string;

  @property({
    type: 'string',
  })
  type?: string;

  @property({
    type: 'string',
  })
  url?: string;


  constructor(data?: Partial<File>) {
    super(data);
  }
}
  • 第三，我在src/目录中创建了一个名为interfaces的新文件夹。在这个新文件夹中，我创建了一个index.ts（主要是遵循导出约定）和storage.interface.ts（这是重要的文件）
// index.ts

export * from './storage.interface';

// storage.interface.ts

import { Container, File } from "../models";


export type Callback<T> = (err: Error | null, reply: T) => void;

export interface IStorageService {
  // container methods
  createContainer(container: Partial<Container>, cb: Callback<Container>): void;
  destroyContainer(containerName: string, cb: Callback<boolean>): void;
  getContainers(cb: Callback<Container[]>): void;
  getContainer(containerName: string, cb: Callback<Container>): void;
  // file methods
  getFiles(containerName: string, options: Object, cb: Callback<File[]>): void;
  getFile(containerName: string, fileName: string, cb: Callback<File>): void;
  removeFile(containerName: string, fileName: string, cb: Callback<boolean>): void;
  // main methods
  upload(containerName: string, req: any, res: any, options: Object, cb: Callback<any>): void;
  download(containerName: string, fileName: string, req: any, res: any, cb: Callback<any>): void;
}
  • 在第四个地方，我创建了container.controller.ts文件，但在此步骤之前，您需要安装运行以下命令的@ loopback / service-proxy：

npm install --save @loopback/service-proxy

// storage-gc.controller.ts

import { inject } from '@loopback/core';
import { serviceProxy } from '@loopback/service-proxy';
import { post, requestBody, del, param, get, getFilterSchemaFor, Request, Response, RestBindings } from '@loopback/rest';
import { Filter } from '@loopback/repository';
import { promisify } from 'util';

import { IStorageService } from '../interfaces';
import { Container, File } from '../models';


export class StorageGcController {
  @serviceProxy('StorageGC') // StorageGC is the name of the datasoruce
  private storageGcSvc: IStorageService;

  constructor(@inject(RestBindings.Http.REQUEST) public request: Request,
    @inject(RestBindings.Http.RESPONSE) public response: Response) { }

  @post('/containers', {
    responses: {
      '200': {
        description: 'Container model instance',
        content: { 'application/json': { schema: { 'x-ts-type': Container } } },
      },
    },
  })
  async createContainer(@requestBody() container: Container): Promise<Container> {
    const createContainer = promisify(this.storageGcSvc.createContainer);
    return await createContainer(container);
  }

  @get('/containers', {
    responses: {
      '200': {
        description: 'Array of Containers model instances',
        content: {
          'application/json': {
            schema: { type: 'array', items: { 'x-ts-type': Container } },
          },
        },
      },
    },
  })
  async findContainer(@param.query.object('filter', getFilterSchemaFor(Container)) filter?: Filter): Promise<Container[]> {
    const getContainers = promisify(this.storageGcSvc.getContainers);
    return await getContainers();
  }

  @get('/containers/{containerName}', {
    responses: {
      '200': {
        description: 'Container model instance',
        content: { 'application/json': { schema: { 'x-ts-type': Container } } },
      },
    },
  })
  async findContainerByName(@param.path.string('containerName') containerName: string): Promise<Container> {
    const getContainer = promisify(this.storageGcSvc.getContainer);
    return await getContainer(containerName);
  }

  @del('/containers/{containerName}', {
    responses: {
      '204': {
        description: 'Container DELETE success',
      },
    },
  })
  async deleteContainerByName(@param.path.string('containerName') containerName: string): Promise<boolean> {
    const destroyContainer = promisify(this.storageGcSvc.destroyContainer);
    return await destroyContainer(containerName);
  }

  @get('/containers/{containerName}/files', {
    responses: {
      '200': {
        description: 'Array of Files model instances belongs to container',
        content: {
          'application/json': {
            schema: { type: 'array', items: { 'x-ts-type': File } },
          },
        },
      },
    },
  })
  async findFilesInContainer(@param.path.string('containerName') containerName: string,
    @param.query.object('filter', getFilterSchemaFor(Container)) filter?: Filter): Promise<File[]> {
    const getFiles = promisify(this.storageGcSvc.getFiles);
    return await getFiles(containerName, {});
  }

  @get('/containers/{containerName}/files/{fileName}', {
    responses: {
      '200': {
        description: 'File model instances belongs to container',
        content: { 'application/json': { schema: { 'x-ts-type': File } } },
      },
    },
  })
  async findFileInContainer(@param.path.string('containerName') containerName: string,
    @param.path.string('fileName') fileName: string): Promise<File> {
    const getFile = promisify(this.storageGcSvc.getFile);
    return await getFile(containerName, fileName);
  }

  @del('/containers/{containerName}/files/{fileName}', {
    responses: {
      '204': {
        description: 'File DELETE from Container success',
      },
    },
  })
  async deleteFileInContainer(@param.path.string('containerName') containerName: string,
    @param.path.string('fileName') fileName: string): Promise<boolean> {
    const removeFile = promisify(this.storageGcSvc.removeFile);
    return await removeFile(containerName, fileName);
  }

  @post('/containers/{containerName}/upload', {
    responses: {
      '200': {
        description: 'Upload a Files model instances into Container',
        content: { 'application/json': { schema: { 'x-ts-type': File } } },
      },
    },
  })
  async upload(@param.path.string('containerName') containerName: string): Promise<File> {
    const upload = promisify(this.storageGcSvc.upload);
    return await upload(containerName, this.request, this.response, {});
  }

  @get('/containers/{containerName}/download/{fileName}', {
    responses: {
      '200': {
        description: 'Download a File within specified Container',
        content: { 'application/json': { schema: { 'x-ts-type': Object } } },
      },
    },
  })
  async download(@param.path.string('containerName') containerName: string,
    @param.path.string('fileName') fileName: string): Promise<any> {
    const download = promisify(this.storageGcSvc.download);
    return await download(containerName, fileName, this.request, this.response);
  }
}

通过此步骤，您的存储组件或连接器最精确地应按预期工作。但是按照Calling other APIS and web services指南的说明改进集成测试的实现，你应该在控制器中使用提供程序而不是@serviceProxy装饰器，为此我在providers文件夹中创建一个名为src/的新文件夹，其中包含以下两个文件：

// index.ts

export * from './storage-service.provider';

// storage-gc-service.provider.ts

import { getService, juggler } from '@loopback/service-proxy';
import { Provider } from '@loopback/core';
import { StorageGCDataSource } from '../datasources/storage-gc.datasource';
import { IStorageService } from '../interfaces';


export class StorageGCServiceProvider implements Provider<IStorageService> {
  constructor(
    protected dataSource: juggler.DataSource = new StorageGCDataSource()

    /* I try to change the line above in the same way that documentation show,
    as follows:

    @inject('datasources.StorageGC')
    protected dataSource: juggler.DataSource = new StorageGCDataSource()

    and also, in the same way that repositories

    @inject('datasources.StorageGC')
    protected dataSource: StorageGCDataSource

    but always return:

    `Error: Cannot resolve injected arguments for StorageGCServiceProvider.[0]:
    The arguments[0] is not decorated for dependency injection, but a value is
    not supplied`
     */
  ) { }

  value(): Promise<IStorageService> {
    return getService(this.dataSource);
  }
}

之后，您需要按以下方式修改src/index.ts和storage-gc.controller.ts

// src/index.ts

import { ApplicationConfig } from '@loopback/core';
import { HocicosCuriososApp } from './application';
import { StorageGCServiceProvider } from './providers';

export { HocicosCuriososApp };

export async function main(options: ApplicationConfig = {}) {
  const app = new HocicosCuriososApp(options);

  /* Add this line, it add a service to the app after that you can
  call them in the controller with dependency injection, like:
  @inject('services.StorageGCService') */
  app.serviceProvider(StorageGCServiceProvider);

  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;
}

// storage-gc.controller.ts

import { inject } from '@loopback/core';
import { post, requestBody, del, param, get, getFilterSchemaFor, Request, Response, RestBindings } from '@loopback/rest';
import { Filter } from '@loopback/repository';
import { promisify } from 'util';

import { IStorageService } from '../interfaces';
import { Container, File } from '../models';


export class StorageGcController {
  @inject('services.StorageGCService')
  private storageGcSvc: IStorageService;

  constructor(@inject(RestBindings.Http.REQUEST) public request: Request,
    @inject(RestBindings.Http.RESPONSE) public response: Response) { }

  @post('/containers', {
    responses: {
      '200': {
        description: 'Container model instance',
        content: { 'application/json': { schema: { 'x-ts-type': Container } } },
      },
    },
  })
  async createContainer(@requestBody() container: Container): Promise<Container> {
    const createContainer = promisify(this.storageGcSvc.createContainer);
    return await createContainer(container);
  }

  @get('/containers', {
    responses: {
      '200': {
        description: 'Array of Containers model instances',
        content: {
          'application/json': {
            schema: { type: 'array', items: { 'x-ts-type': Container } },
          },
        },
      },
    },
  })
  async findContainer(@param.query.object('filter', getFilterSchemaFor(Container)) filter?: Filter): Promise<Container[]> {
    const getContainers = promisify(this.storageGcSvc.getContainers);
    return await getContainers();
  }

  @get('/containers/{containerName}', {
    responses: {
      '200': {
        description: 'Container model instance',
        content: { 'application/json': { schema: { 'x-ts-type': Container } } },
      },
    },
  })
  async findContainerByName(@param.path.string('containerName') containerName: string): Promise<Container> {
    const getContainer = promisify(this.storageGcSvc.getContainer);
    return await getContainer(containerName);
  }

  @del('/containers/{containerName}', {
    responses: {
      '204': {
        description: 'Container DELETE success',
      },
    },
  })
  async deleteContainerByName(@param.path.string('containerName') containerName: string): Promise<boolean> {
    const destroyContainer = promisify(this.storageGcSvc.destroyContainer);
    return await destroyContainer(containerName);
  }

  @get('/containers/{containerName}/files', {
    responses: {
      '200': {
        description: 'Array of Files model instances belongs to container',
        content: {
          'application/json': {
            schema: { type: 'array', items: { 'x-ts-type': File } },
          },
        },
      },
    },
  })
  async findFilesInContainer(@param.path.string('containerName') containerName: string,
    @param.query.object('filter', getFilterSchemaFor(Container)) filter?: Filter): Promise<File[]> {
    const getFiles = promisify(this.storageGcSvc.getFiles);
    return await getFiles(containerName, {});
  }

  @get('/containers/{containerName}/files/{fileName}', {
    responses: {
      '200': {
        description: 'File model instances belongs to container',
        content: { 'application/json': { schema: { 'x-ts-type': File } } },
      },
    },
  })
  async findFileInContainer(@param.path.string('containerName') containerName: string,
    @param.path.string('fileName') fileName: string): Promise<File> {
    const getFile = promisify(this.storageGcSvc.getFile);
    return await getFile(containerName, fileName);
  }

  @del('/containers/{containerName}/files/{fileName}', {
    responses: {
      '204': {
        description: 'File DELETE from Container success',
      },
    },
  })
  async deleteFileInContainer(@param.path.string('containerName') containerName: string,
    @param.path.string('fileName') fileName: string): Promise<boolean> {
    const removeFile = promisify(this.storageGcSvc.removeFile);
    return await removeFile(containerName, fileName);
  }

  @post('/containers/{containerName}/upload', {
    responses: {
      '200': {
        description: 'Upload a Files model instances into Container',
        content: { 'application/json': { schema: { 'x-ts-type': File } } },
      },
    },
  })
  async upload(@param.path.string('containerName') containerName: string): Promise<File> {
    const upload = promisify(this.storageGcSvc.upload);
    return await upload(containerName, this.request, this.response, {});
  }

  @get('/containers/{containerName}/download/{fileName}', {
    responses: {
      '200': {
        description: 'Download a File within specified Container',
        content: { 'application/json': { schema: { 'x-ts-type': Object } } },
      },
    },
  })
  async download(@param.path.string('containerName') containerName: string,
    @param.path.string('fileName') fileName: string): Promise<any> {
    const download = promisify(this.storageGcSvc.download);
    return await download(containerName, fileName, this.request, this.response);
  }
}

这就是全部，按照这些步骤，您必须使存储组件运行良好。祝好运！

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