NestJS 依赖注入 – 从解析器的构造函数中删除垃圾

huangapple
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英文:

NestJS dependency injection - delete garbage from constructor in resolver

问题

我已经看到你的代码并了解了你的问题。你的问题似乎与依赖注入有关，特别是在NestJS中如何正确注入依赖。

首先，你尝试使用UserRepoSymbol来提供UserPostgresql，然后在UserService中注入它，这是一个正确的做法。但是，根据你的错误消息，问题可能出在配置文件的导入和环境变量的设置上。

确保以下几点：

  1. 确保你的.env文件路径正确，并且文件包含所需的环境变量。你可以在 dotenv.config({ path: ENV_FILE_PATH }) 这一行之后添加 console.log(process.env) 来检查是否成功加载了环境变量。

  2. 确保 UserRepoSymbol 的值与你的提供者名称一致。在你的模块中，你提供了一个名称为Object的提供者，但在注入时使用的是 UserRepoSymbol。确保它们匹配。

  3. 检查 UserPostgresql 是否正确导入并在 providers 数组中添加到 UserModule 中。

如果你仍然遇到问题，可以提供更多关于错误消息的信息，以便我能够提供更具体的帮助。

英文:

So I have been working on a NestJs+Graphql+Postgresql application using ddd architecture. And now it just adds user to a database.

I have the following user.resolver in the presentation layer:

  1. @Resolver(of => UserBaseWithPassword)
  2. export class UserResolver {
  3.     private readonly userApplication: UserApplication
  4.     constructor(private readonly userRepo: UserPostgresql) {
  5.         const userService = new UserService(userRepo)
  6.         this.userApplication = new UserApplication(userService)
  7.     }
  8.     
  9.     @Query(returns => String)
  10.     users() : string {
  11.         return "";
  12.     }
  14.     @Mutation(returns => String)
  15.     async createUser(@Args('createUserDTO') createUserWithPasswordDTO: CreateUserWithPasswordDTO): Promise<string> {
  16.         return await this.userApplication.create(createUserWithPasswordDTO=createUserWithPasswordDTO)
  17.     }
  19. }

It works fine, but I need to get rid of garbage in the constructor.
Here is my application layer's
user.ts :

  1. export class UserApplication{
  2.     constructor(private userService: UserService) {}
  4.     async create(createUserWithPasswordDTO: CreateUserWithPasswordDTO): Promise<string> {
  5.         return await this.userService.create(createUserWithPasswordDTO=createUserWithPasswordDTO);
  6.     }
  7. }

In the domain layer i have user.service.ts :

  1. @Injectable()
  2. export class UserService {
  3.     constructor(private readonly userRepo: IUserRepo) {}
  5.     async create(createUserWithPasswordDTO: CreateUserWithPasswordDTO): Promise<string> {
  6.         this.validateEmail(createUserWithPasswordDTO.email)
  7.         this.validatePassword(createUserWithPasswordDTO.password)
  8.         try{
  9.             createUserWithPasswordDTO.password = await this.hashPassword(createUserWithPasswordDTO.password);
  10.             return await this.userRepo.create(createUserWithPasswordDTO);
  11.         }catch(e){
  12.             throw new Error("DEFAULT_USER_ERROR"+e)
  13.         }
  14.     }
  16.     private async hashPassword(password: string): Promise<string> {
  17.         const saltRounds = process.env.PASSWORD_SALT_ROUNDS;
  18.         return await bcrypt.hash(password, saltRounds);;
  19.     }
  21.     private validateEmail(email: string): boolean {
  22.         if(email.length < MIN_EMAIL_LENGTH)
  23.             throw new Error(EMAIL_MIN_LENGTH_TEXT)
  24.         if(email.length > MAX_EMAIL_LENGTH)
  25.             throw new Error(EMAIL_MAX_LENGTH_TEXT)
  26.         if(!EMAIL_REGEX.test(email))
  27.             throw new Error(EMAIL_REGEX_TEXT)
  28.         return true;
  29.     }
  31.     private validatePassword(password: string): boolean {
  32.         if(password.length < MIN_PASSWORD_LENGTH || password.length > MAX_PASSWORD_LENGTH)
  33.             throw new Error(PASSWORD_LENGTH_ERROR_TEXT)
  34.         if(!PASSWORD_HAS_NUMBER_REGEX.test(password))
  35.             throw new Error(PASSWORD_NOT_INCLUDES_NUMBER_TEXT)
  36.         if(!PASSWORD_HAS_LETTER_REGEX.test(password))
  37.             throw new Error(PASSWORD_NOT_INCLUDES_LETTER_TEXT)
  38.         return true;
  39.     }
  40. }

and an Interface user.repo :

  1. import { CreateUserWithPasswordDTO } from "./dtos/create-user.dto";
  3. export interface IUserRepo  {    
  4.     create(createUserWithPasswordDTO: CreateUserWithPasswordDTO): Promise<string>
  5. }

And lastly, in the infrustructure layer I have repo.ts, that implements interface UserRepo :

  1. @Injectable()
  2. export class UserPostgresql implements IUserRepo{
  3.     constructor(@InjectDataSource() private dataSource: DataSource) {}
  4.     async create(createUserWithPasswordDTO: CreateUserWithPasswordDTO): Promise<string> {
  5.         const parameters = [uuidv4(), createUserWithPasswordDTO.email, createUserWithPasswordDTO.password]
  6.         const reply = await this.dataSource.query(CREATE_USER, parameters)
  7.         return reply[0].id
  8.     }
  9. }

I mention all above in the user.module :

  1. import * as dotenv from 'dotenv';
  3. const ENV_FILE_PATH = './ci/postgres/.env'
  4. dotenv.config({path: ENV_FILE_PATH});
  6. @Module({
  7.   imports: [TypeOrmModule.forFeature([User])],
  8.   controllers: [],
  9.   providers: [ 
  10.     Object,
  11.     UserPostgresql,
  12.     UserService,
  13.     UserApplication,
  14.     UserPostgresql,
  15.     UserResolver
  16.   ]
  17. })
  18. export class UserModule {}

I write Object in the @Module, because program doesn't compile without it which is also an issue.

I tried to write in user.module something like

  1. {
  2.       provide: UserRepoSymbol,
  3.       useClass: UserPostgresql,
  4. },

then changing constructor in the user.service to :

  1. constructor(@Inject(UserRepoSymbol) private readonly userRepo: IUserRepo) {}

and also changing the user.resolver's constructor just to:


constructor(private readonly userApplication: UserApplication) {}

but it seems not to work and i get an error :

  1. TypeError: Cannot read properties of undefined (reading 'create')
  2.     at UserApplication.create (C:\path\api-service\src\application\user.ts:8:39)
  3.     at UserResolver.createUser (C:\path\src\presentation\user\user.resolver.ts:20:43)...

答案1

得分: 0

我忘记了在 user.application 中使用 @Injectable 装饰器。

英文:

I forgot @Injectable decorator in user.application

huangapple
  • 本文由 发表于 2023年6月25日 22:07:31
  • 转载请务必保留本文链接：https://go.coder-hub.com/76550803.html
  • dependency-injection
  • graphql
  • nestjs
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