exception filter

nest-start/src/cats/cats.controller.ts

@@ -1,12 +1,29 @@
-import { Controller, Delete, Get, Patch, Post, Put } from "@nestjs/common";
+import {
+  Controller,
+  Delete,
+  Get,
+  HttpException,
+  HttpStatus,
+  Patch,
+  Post,
+  Put,
+  UseFilters,
+} from "@nestjs/common";
 import { CatsService } from "./cats.service";
+import { HttpExceptionFilter } from "src/http-exception.filter";
 
 @Controller("cats")
 export class CatsController {
   constructor(private readonly catsService: CatsService) {}
 
   @Get()
+  @UseFilters(HttpExceptionFilter)
   getAllCat() {
+    // throw new HttpException(
+    //   { customized: true, success: false, message: "api is broken" },
+    //   HttpStatus.UNAUTHORIZED,
+    // );
+    throw new HttpException("api is broken", HttpStatus.UNAUTHORIZED);
     return "all cat";
   }
 

nest-start/src/http-exception.filter.ts

@@ -0,0 +1,34 @@
+import {
+  ArgumentsHost,
+  Catch,
+  ExceptionFilter,
+  HttpException,
+} from "@nestjs/common";
+import { Response, Request } from "express";
+
+@Catch(HttpException)
+export class HttpExceptionFilter implements ExceptionFilter {
+  catch(exception: HttpException, host: ArgumentsHost) {
+    const ctx = host.switchToHttp();
+    const response = ctx.getResponse<Response>();
+    const request = ctx.getRequest<Request>();
+    const status = exception.getStatus();
+    const error = exception.getResponse() as
+      | string
+      | { error: string; statusCode: number; message: string | string[] };
+
+    if (typeof error === "string") {
+      response.status(status).json({
+        timestamp: new Date().toISOString(),
+        path: request.url,
+        error,
+      });
+    } else {
+      response.status(status).json({
+        timestamp: new Date().toISOString(),
+        path: request.url,
+        ...error,
+      });
+    }
+  }
+}

nest-start/src/main.ts

@@ -1,9 +1,11 @@
 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);
   app.enableCors();
+  app.useGlobalFilters(new HttpExceptionFilter());
   await app.listen(process.env.PORT ?? 8000);
 }
 bootstrap();