过滤器

作用

主要用于捕获异常,一般用于全局

默认

{
  "statusCode": 500,
  "message": "Internal server error"
}

过滤器使用

创建一个过滤器

import {
  ExceptionFilter,
  Catch,
  ArgumentsHost,
  HttpException,
  HttpStatus,
} from "@nestjs/common";
import { Request, Response } from "express";

@Catch(HttpException)
export class GlobalExceptionFilter implements ExceptionFilter {
  catch(exception: any, host: ArgumentsHost) {
    const ctx = host.switchToHttp();
    const response = ctx.getResponse<Response>();
    const request = ctx.getRequest<Request>();
    // 状态码
    const status =
      exception instanceof HttpException
        ? exception.getStatus()
        : HttpStatus.INTERNAL_SERVER_ERROR;
    const message =
      exception instanceof HttpException ? exception.message : exception.stack;
    response.status(status).json({
      code: status,
      timestamp: new Date().toLocaleString(),
      path: request.url,
      message: message,
    });

    response.status(status).json();
  }
}

挂载到全局

app.modules.ts 中 找到

providers 里面改变 providers 对应的就是名字

useClass 对应的就是你要改变的那个类名

import { Module } from "@nestjs/common";
import { LoginModule } from "./Login/login.module";
// 过滤器
import { GlobalExceptionFilter } from "./Global/filter/global.filter";
import { APP_FILTER } from "@nestjs/core";
@Module({
  imports: [LoginModule],
  controllers: [],
  providers: [
    {
      provide: APP_FILTER,
      useClass: GlobalExceptionFilter,
    },
  ],
})
export class AppModule {}

挂载到单个

• 找到你要找到的路由文件,直接挂载

import {
  Body,
  Controller,
  Delete,
  Get,
  HttpException,
  Inject,
  Param,
  Patch,
  Post,
  UseFilters,
} from "@nestjs/common";
import { LoginService } from "../service/login.service";
import { CustomExceptionFilter } from "../../Global/filter/customfilter";
@Controller("logins")
export class LoginController {
  @Inject()
  private loginService: LoginService;

  constructor() {}

  @Get()
  findAll() {
    return this.loginService.findAll();
  }

  @Get("test")
  @UseFilters(CustomExceptionFilter)
  findAlltest() {
    throw new HttpException("内部错误", 402);
  }
}

注意

注意

1. 这样每次抛出异常出来,会自动给你转化成 json 格式
2. 要是绑定到路由上面.它只会总路由上面的过滤器,全局的它不在走了