Nestjs（五）异常处理方式（异常过滤器）

$ nest g f http-exception

// 这是创建后的文件初始内容
import { ArgumentsHost, Catch, ExceptionFilter } from '@nestjs/common';
@Catch()
export class HttpExceptionFilter<T> implements ExceptionFilter {
  catch(exception: T, host: ArgumentsHost) {
    // 这里就是拦截到的异常，需要处理并抛出给到前台方便直观看到问题...
    // 输出拦截到的错误异常
    console.log(exception)
  }
}

import { ArgumentsHost, Catch, ExceptionFilter, HttpException } from '@nestjs/common';
// 如果不引用，可能会导致类型关联错误
import { Response, Request } from 'express';
// 捕获 HttpException 错误;  如果 @Catch() 里面没有参数, 则捕获所有错误
// 可以支持多个 @Catch(HttpException, xxx, xxx)
// 支持的内置异常列表文档：https://docs.nestjs.cn/10/exceptionfilters?id=%e5%86%85%e7%bd%aehttp%e5%bc%82%e5%b8%b8
@Catch(HttpException)
export class HttpExceptionFilter<T> implements ExceptionFilter {
  // exception：当前正在处理的异常对象
  // host：传递给原始处理程序的一个包装（Response/Request）引用参数
  catch(exception: HttpException, host: ArgumentsHost) {
    // 获取上下文
    const ctx = host.switchToHttp();
    // 响应对象，跟接口中 @Response @Res 取到的一样
    const response = ctx.getResponse<Response>();
    // 请求对象，跟接口中 @Request @Req 取到的一样
    const request = ctx.getRequest<Request>();
    // 异常状态
    const status = exception.getStatus();
    // 抛出错误日志
    response
      .status(status)
      .json({
        dzm: '测试字段',
        statusCode: status,
        timestamp: new Date().toISOString(),
        path: request.url
      });
  }
}

import { Controller, Get, Body, Query, Post, Param, Request, Req, Res, Redirect, HttpCode, HttpException, HttpStatus, UseFilters } from '@nestjs/common';
import { UserService } from './user.service';
// 这里也需要引入
import { HttpExceptionFilter } from 'src/http-exception.filter';
@Controller('user')
export class UserController {
  constructor(private readonly userService: UserService) { }
  @Get('/dzm')
  // 添加上过滤器
  @UseFilters(new HttpExceptionFilter())
  getDzm(@Req() req: any, @Res() res: any): any {
    // 故意抛出异常进行测试
    throw new HttpException('Forbidden', HttpStatus.FORBIDDEN)
    res.send(req.query)
  }
}

import { Controller, Get, Body, Query, Post, Param, Request, Req, Res, Redirect, HttpCode, HttpException, HttpStatus, UseFilters } from '@nestjs/common';
import { UserService } from './user.service';
import { HttpExceptionFilter } from 'src/http-exception.filter';
@Controller('user')
@UseFilters(new HttpExceptionFilter())
export class UserController {
  constructor(private readonly userService: UserService) { }
  @Get('/dzm')
  getDzm(@Req() req: any, @Res() res: any): any {
    // 故意抛出异常进行测试
    throw new HttpException('Forbidden', HttpStatus.FORBIDDEN)
    res.send(req.query)
  }
}

import { NestFactory } from '@nestjs/core';
import { AppModule } from './app.module';
import { HttpExceptionFilter } from './http-exception.filter';
async function bootstrap() {
  const app = await NestFactory.create(AppModule);
  // 全局注册异常过滤器
  app.useGlobalFilters(new HttpExceptionFilter())
  await app.listen(3000);
}
bootstrap();

import { Module } from '@nestjs/common';
import { AppController } from './app.controller';
import { AppService } from './app.service';
import { UserModule } from './user/user.module';
import { LoginModule } from './login/login.module';
import { APP_FILTER } from '@nestjs/core';
import { HttpExceptionFilter } from './http-exception.filter';
@Module({
  imports: [UserModule, LoginModule],
  controllers: [AppController],
  providers: [
    AppService,
    // 这样注册即可，效果一样，可以根据需要使用此技术添加任意数量的过滤器
    {
      provide: APP_FILTER,
      useClass: HttpExceptionFilter,
    },
  ],
})
export class AppModule { }