Nestjs 管道验证DTO

一、创建验证管道pipe

1、创建p模块

nest g res p

2、创建验证管道

nest g pi p

二、安装验证器 

npm i --save class-validator class-transformer

代码 ：

import { IsNotEmpty, IsString } from "class-validator";
import { isString } from "class-validator/types/decorator/decorators";

export class CreatePDto {
    @isNotEmpty()   // 验证是否为空
    @isString()     // 验证是否为字符串
    name: string;
    
    @IsNotEmpty()
    age: number
}

 截图：

 三、controller 使用管道

四、transform 实现验证 

p.pipe.ts 文件 逻辑代码：

通过 validate 验证 DTO 返回一个promise 的错误信息 

import { ArgumentMetadata, HttpException, HttpStatus, Injectable, PipeTransform } from '@nestjs/common';
import { plainToInstance } from 'class-transformer';
import { validate } from 'class-validator';

@Injectable()
export class PPipe implements PipeTransform {
    async transform(value: any, metadata: ArgumentMetadata) {
        const DTO = plainToInstance(metadata.metatype, value);
        
        const errors = await validate(DTO);
        if(errors.length > 0) {
            throw new HttpException(errors, HttpStatus.BAD_REQUEST);        
        }
        return value;
    }
}

 

 五、注册全局DTO验证管道

main.ts 文件添加一下内容：

import { VersioningType } from '@nestjs/common';

app.useGlobalPipes(new ValidationPipe());

import { VersioningType, ValidationPipe } from '@nestjs/common';
import { NestFactory } from '@nestjs/core';
import { AppModule } from './app.module';
import * as session from 'express-session';
import { NestExpressApplication } from '@nestjs/platform-express/interfaces';
import { join } from 'path';

async function bootstrap() {
    const app = await NestFactory.create(AppModule);
    app.useGlobalPipes(new ValidationPipe());
    await app.listen(3000);
}
bootstrap();

请求截图：