done with backend

src/url-shortener/response.interface.ts

@@ -0,0 +1,5 @@
+export interface ApiResponse {
+  data?: string;
+  error?: string;
+  status: number;
+}

src/url-shortener/url-shortener.controller.ts

@@ -1,26 +1,35 @@
-import { Controller, Post, Body, Get, Param, Redirect, HttpException, HttpStatus } from '@nestjs/common';
+import { Controller, Post, Body, Get, Param, HttpException, HttpStatus, Res } from '@nestjs/common';
 import { UrlShortenerService } from './url-shortener.service';
+import { ApiResponse } from './response.interface';
+import { Response } from 'express';
 
 @Controller('url-shortener')
 export class UrlShortenerController {
   constructor(private readonly urlShortenerService: UrlShortenerService) {}
 
   @Post('shorten')
-  async shortenUrl(@Body('url') url: string): Promise<{ shortUrl: string }> {
+  async shortenUrl(@Body('url') url: string): Promise<ApiResponse> {
     if (!url) {
       throw new HttpException('URL is required', HttpStatus.BAD_REQUEST);
     }
+    try {
       const shortUrl = await this.urlShortenerService.generateShortUrl(url);
-    return { shortUrl };
+      return { data: shortUrl, status: HttpStatus.CREATED };
+    } catch (error) {
+      return { error: error.message, status: HttpStatus.BAD_REQUEST };
+    }
   }
 
   @Get(':shortUrl')
-  @Redirect()
-  async resolveShortUrl(@Param('shortUrl') shortUrl: string) {
+  async resolveShortUrl(@Param('shortUrl') shortUrl: string, @Res() res: Response) {
+    try {
       const originalUrl = this.urlShortenerService.getOriginalUrl(shortUrl);
       if (!originalUrl) {
-      throw new HttpException('URL not found!', HttpStatus.NOT_FOUND);
+        return res.redirect('http://localhost:3000/404');
+      }
+      return res.redirect(originalUrl);
+    } catch (error) {
+      throw new HttpException('An error occurred', HttpStatus.INTERNAL_SERVER_ERROR);
     }
-    return { url: originalUrl };
   }
 }

src/url-shortener/url-shortener.service.ts

@@ -1,6 +1,7 @@
 import { Injectable } from '@nestjs/common';
 import * as shortid from 'shortid';
 import { DnsService } from '../dns/dns.service';
+import { HttpException, HttpStatus } from '@nestjs/common';
 
 
 @Injectable()
@@ -11,19 +12,21 @@ export class UrlShortenerService {
   constructor(private readonly dnsService: DnsService) {}
 
   async generateShortUrl(originalUrl: string): Promise<string> {
-    if(!originalUrl) {
-      throw new Error('URL is required');
+    if (!originalUrl) {
+      throw new HttpException('URL is required', HttpStatus.BAD_REQUEST);
     }
-    let isValid = await this.dnsService.isValidUrl(originalUrl);
-    if(!isValid) {
-      throw new Error('URL is invalid');
+    const isValid = await this.dnsService.isValidUrl(originalUrl);
+    if (!isValid) {
+      throw new HttpException('URL is invalid', HttpStatus.BAD_REQUEST);
     }
-    let shortUrl = "tiny." + shortid.generate() + ".com";
+    const shortUrl = "tiny." + shortid.generate() + ".com";
     this.urlMap.set(shortUrl, originalUrl);
-    return shortUrl
+    return shortUrl;
   }
 
   getOriginalUrl(shortUrl: string): string | undefined {
-    return this.urlMap.get(shortUrl);
+    let url: string | undefined = this.urlMap.get(shortUrl);
+    if (url) return url;
+    return undefined;
   }
 }