如何在loopback 4组件中注入configure用户模型来设置关系？

Question

按照DRY的要求，我想在扩展（回环组件）中包含我的业务逻辑，但是，当定义模型时，我想指定一个属性的 belongsTo关系，在LB3中，我想通过定义以下模块并通过配置覆盖来实现。

在LB3中，我想通过定义以下模块并通过配置覆盖来实现同样的功能。

module.exports = (blogModels, options) => {
  const debug = require('debug')('component:blog:postlike:model');
  const {userModel} = options;
  const postLikeModel = blogModels.PostLike;
  const postModel = blogModels.Post;

  // update relationships
  postModel.belongsTo(userModel,
    {as: 'userCreated', foreignKey: 'createdBy'});
  postModel.belongsTo(userModel,
    {as: 'userDeleted', foreignKey: 'deletedBy'});
  postModel.belongsTo(postModel,
    {as: 'post', foreignKey: 'postId'});

  let postLike = {};
  return postLike;
};

另外，我想知道如何让开发人员指定模型 以防他想指定一个自定义的模型。

在LB3中，可以这样做。https:/github.compbalancomponent-blogblobmasterlibmodelsindex.js#L51-L63。

const debug = require('debug')('component:blog');
const accessLogger = require('../middleware/access-logger');
const userContext = require('../middleware/user-context');
const logger = require('../middleware/logging');
const reqLogger = require('../middleware/request-logging');

module.exports = function componentBlog(app, options) {
  debug('initializing component');
  const {loopback} = app;
  options = options || {};

  let dataSource = options.dataSource;
  /* istanbul ignore if */
  if (typeof dataSource === 'string') {
    dataSource = app.dataSource[dataSource];
  }
  const blogModels = require('./component-blog-models')(dataSource);
  const userModel = loopback.findModel(options.userModel) ||
      loopback.getModelByType(loopback.User);
  debug('User model: %s', userModel.modelName);

  const venueModel = loopback.findModel(options.venueModel);
  // debug('Venue model: %s', venueModel.modelName);

  // Initialize middleware
  app.middleware('initial:before', logger());
  app.middleware('initial:before', reqLogger());
  app.middleware('auth:after', userContext());
  app.middleware('routes:before', accessLogger());

  let users = {};
  let venue = {};

  let internalConfig = {
    userModel: userModel,
    venueModel: venueModel,
  };

  // specific to app
  const post = require('./Post')(blogModels, internalConfig);
  const postLike = require('./PostLike')(blogModels, internalConfig);
  const postMention = require('./PostMention')(blogModels, internalConfig);
  const postShare = require('./PostShare')(blogModels, internalConfig);
  const postComment = require('./PostComment')(blogModels, internalConfig);
  const commentComment =
    require('./CommentComment')(blogModels, internalConfig);
  const postMedia = require('./PostMedia')(blogModels, internalConfig);
  const blogReported = require('./BlogReported')(blogModels, internalConfig);

  let customModels = options.models || {};
  let models = {
    user: customModels.users || users,
    venue: customModels.venue || venue,
    blogReported: customModels.blogReported || blogReported,
    post: customModels.post || post,
    postLike: customModels.postLike || postLike,
    postMention: customModels.postMention || postMention,
    postShare: customModels.postShare || postShare,
    postComment: customModels.postComment || postComment,
    commentComment: customModels.commentComment || commentComment,
    postMedia: customModels.postMedia || postMedia,
  };

  return models;
};

然后，在引导脚本中，我们可以提供必要的覆盖。

https:/github.compbalancomponent-blogblobmastertestfixturessimple-appserverboot003-component-blog.js#L7。

module.exports = function blog(app) {
  var blog = require('../../../../../lib');

  var options = {
    // custom user model
    userModel: 'user', // specify your custom user model
    uploadMediaUrl: '/api/containers/blog-media/upload',
    baseUrl: 'http://0.0.0.0:3000',

    // Data source for metadata persistence
    dataSource: app.dataSources.db,
  };
  app.set('component-blog', options);
  blog(app, options);
};

我正在为LB4寻找一个类似的例子。不幸的是，目前的例子大多反映的是应用程序而不是组件。

Answer 1

你是否尝试过新的认证组件？https:/loopback.iodocenlb4Loopback-component-authentication.html。

它有一个绑定，可以解救端点的认证用户。只需在控制器的构造函数中注入用户（我不确定在端点中注入是否有效）。

import {SecurityBindings, UserProfile} from '@loopback/security';

 @inject(SecurityBindings.USER)
    private userProfile: UserProfile,

一个简单的例子（摘自官方文档，在我放在最上面的链接里）。

import {inject} from '@loopback/context';
import {AuthenticationBindings, authenticate} from '@loopback/authentication';
import {SecurityBindings, securityId, UserProfile} from '@loopback/security';
import {get} from '@loopback/rest';

export class WhoAmIController {
  constructor(
    // `AuthenticationBindings.CURRENT_USER` is now an alias of
    // `SecurityBindings.USER` in @loopback/security
    @inject(SecurityBindings.USER)
    private userProfile: UserProfile,
  ) {}

  @authenticate('basic')
  @get('/whoami')
  whoAmI(): string {
    // `securityId` is Symbol to represent the security id of the user,
    // typically the user id. You can find more information of `securityId` in
    // https://loopback.io/doc/en/lb4/Security
    return this.userProfile[securityId];
  }
}