英文:
How to add unique field validation in nest js with class-validator
问题
我了解你的问题，你在NestJS中使用class-validator进行数据库字段验证时遇到了一些问题。在你的代码中，UniqueFieldValidator类的构造函数依赖于userService，但在validate函数中，userService却变成了undefined。这可能是由于依赖注入的问题造成的。以下是一种可能的解决方案：
首先，确保在UniqueFieldValidator类中的构造函数上使用了@Injectable()装饰器，以便NestJS可以正确注入userService。你的代码中已经包含了这个装饰器，这是正确的。
接下来，检查一下你的NestJS模块（UserModule）的提供者数组中是否正确引入了UserService和UniqueFieldValidator。你的代码中也已经包含了它们，这也是正确的。
然后，确保你的UserModule正确导入了TypeOrmModule，并且已经正确配置了实体（User）。你的代码中也已经包含了这些部分。
最后，确保你的UniqueFieldValidator被正确引用并传递给@Validate装饰器。
总结一下，根据你提供的代码片段，似乎配置和装饰器都已经正确设置。如果仍然遇到问题，可以检查以下几点：
- 确保NestJS应用程序正确启动，并且
UserModule已被正确引入。 - 检查是否有任何循环依赖问题，可能会导致
userService未能正确注入。
如果仍然存在问题，可以提供更多关于应用程序的信息，以便更深入地了解问题所在。
英文:
How to do validation with database like unique filed validation in nest JS using the class validator?
I created a custom validation class and tried it. But userService was undefined when I console log that service in the validate function.
import { ValidatorConstraint, ValidatorConstraintInterface, ValidationArguments } from 'class-validator';import { Injectable } from '@nestjs/common';import { UserService } from './user.service';@ValidatorConstraint({ name: 'unique', async: true })@Injectable()export class UniqueFieldValidator implements ValidatorConstraintInterface {constructor(private readonly userService: UserService) {}validate = async (value: any, args: ValidationArguments): Promise<boolean> => {console.log(this.userService); // <-- This log prints undefinedconst [entityClass, fieldName] = args.constraints;const entity = await this.userService.findByFieldValue({ [fieldName]: value });return !entity;}defaultMessage(args: ValidationArguments) {const [entityClass, fieldName] = args.constraints;return `${fieldName} must be unique`;}}
I have called this class in side createUserDto Class as below.
import { IsEnum, IsNotEmpty, MinLength, Validate } from "class-validator";import { CompanyStatuses } from "src/company/dto/company.enums";import { User } from "../entities/user.entity";import { UniqueFieldValidator } from "../unique-field-validator";export class CreateUserDto {@IsNotEmpty()@MinLength(3)@Validate(UniqueFieldValidator, [User, 'username'])username: string}
UniqueFieldValidator class is calling successfully.
But because that userServices is undefined in the validate function when I sent the request to create a user, it's returning the error message saying
TypeError: Cannot read properties of undefined (reading 'findByFieldValue')at UniqueFieldValidator.validate
If anyone has experience this in NestJs with class-validator please help me. Thank you!
P.S.
Below code shows how i have written my userModule and i have added both UserService and Validator class to the Providers array.also have placed @injectable() decorator top of the UserService class. but it's not working still.
import { Module } from '@nestjs/common';import { UserService } from './user.service';import { UserController } from './user.controller';import { TypeOrmModule } from '@nestjs/typeorm';import { User } from './entities/user.entity';import { UniqueFieldValidator } from './unique-field-validator';@Module({controllers: [UserController],providers: [UserService,UniqueFieldValidator],imports: [TypeOrmModule.forFeature([User])],exports: [UserService,TypeOrmModule]})export class UserModule { }
答案1
得分: 2
Sure, here's the translation of the provided text:
是的！我找到了解决方案，并将其发布在我的问题中，以帮助将来遇到此问题的人。
只需在根方法中添加 useContainer(app.select(AppModule), { fallbackOnErrors: true });。
然后我的 main.ts 文件如下所示。
import { NestFactory } from '@nestjs/core';import { AppModule } from './app.module';import { useContainer } from 'class-validator';async function bootstrap() {const app = await NestFactory.create(AppModule);useContainer(app.select(AppModule), { fallbackOnErrors: true });await app.listen(3000);}bootstrap();
我将这个帖子发布在我的问题中，以帮助将来的某人。
英文:
Yeah! I found a solution and posting it to my own question for help to someone getting this issue in the future.
Just add useContainer(app.select(AppModule), { fallbackOnErrors: true }); in your root method.
Then my main.ts was like this.
import { NestFactory } from '@nestjs/core';import { AppModule } from './app.module';import { useContainer } from 'class-validator';async function bootstrap() {const app = await NestFactory.create(AppModule);useContainer(app.select(AppModule), { fallbackOnErrors: true });await app.listen(3000);}bootstrap();
I'm posting this to my own question to help someone in the future.
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