chore:refactor services/integrations change every class to Singelton pattern

Author: aayushpagare21-compcoder

src/app/api/asp-ai/evaluate-answer/route.ts

@@ -8,23 +8,12 @@ import { evaluateAnswer } from "@/app/server/services/ai/evaluateAnswer";
 import { validateEvaluateAnswerAPIFormData } from "@/app/server/validators/asp-ai.validators";
 import { getAuthenticatedUser } from "@/app/server/utils/getAuthUserDetails";
 import { User } from "@prisma/client";
-import { Duration, Ratelimit } from "@upstash/ratelimit";
-import { Redis } from "@upstash/redis";
 import { ErrorCodes } from "@/app/lib/constants";
+import RatelimitService from "@/app/server/services/integrations/rateLimitig.service";
 
-const redis = new Redis({
-  url: process.env.UPSTASH_REDIS_URL,
-  token: process.env.UPSTASH_REDIS_TOKEN,
-});
-const ratelimit = new Ratelimit({
-  redis: redis,
-  limiter: Ratelimit.fixedWindow(
-    parseInt(process.env.DEFAULT_API_TOKENS!),
-    process.env.DEFAULT_API_TOKEN_FILLED_AFTER! as Duration,
-  ),
-});
-const s3 = new S3Service(process.env.AWS_S3_BUCKET_NAME!);
-const textExtract = new TextractService(process.env.AWS_S3_BUCKET_NAME!);
+const s3 = S3Service.getInstance(process.env.AWS_S3_BUCKET_NAME!);
+const textExtract =TextractService.getInstance(process.env.AWS_S3_BUCKET_NAME!);
+const rl = RatelimitService.getInstance().getRatelimit()
 
 export const maxDuration = 60;
 
@@ -41,7 +30,7 @@ export async function POST(req: Request) {
 
     // Rate limiting
     //apiPath:keyPerfix:key
-    const rateLimitCheck = await ratelimit.limit(
+    const rateLimitCheck = await rl.limit(
       `/asp-ai/evaluate-answer:userId:${user.id}`,
     );
 

src/app/server/services/answers.service.ts

@@ -1,4 +1,4 @@
-import { prisma } from "../db/prisma";
+import { prisma } from "../utils/prisma";
 
 export async function createAnswer({
   id,

src/app/server/services/integrations/rateLimitig.service.ts

@@ -0,0 +1,38 @@
+import { Duration, Ratelimit } from "@upstash/ratelimit";
+import { Redis } from "@upstash/redis";
+
+class RatelimitService {
+  private static instance: RatelimitService;
+  private ratelimitInstance: Ratelimit;
+
+  // Private constructor to prevent direct instantiation
+  private constructor() {
+    const redisClient = new Redis({
+      url: process.env.UPSTASH_REDIS_URL!,
+      token: process.env.UPSTASH_REDIS_TOKEN!,
+    });
+
+    this.ratelimitInstance = new Ratelimit({
+      redis: redisClient,
+      limiter: Ratelimit.fixedWindow(
+        parseInt(process.env.DEFAULT_API_TOKENS!),
+        process.env.DEFAULT_API_TOKEN_FILLED_AFTER! as Duration,
+      ),
+    });
+  }
+
+  // Static method to get the singleton instance
+  public static getInstance(): RatelimitService {
+    if (!RatelimitService.instance) {
+      RatelimitService.instance = new RatelimitService();
+    }
+    return RatelimitService.instance;
+  }
+
+  // Expose the Ratelimit instance
+  public getRatelimit(): Ratelimit {
+    return this.ratelimitInstance;
+  }
+}
+
+export default RatelimitService;

src/app/server/services/integrations/s3.service.ts

@@ -2,12 +2,12 @@ import { S3Client, GetObjectCommand } from "@aws-sdk/client-s3";
 import { Upload } from "@aws-sdk/lib-storage";
 import { Readable } from "stream";
 
-// TODO: Singleton pattern
 export class S3Service {
+  private static instance: S3Service;
   private s3Client: S3Client;
   private bucketName: string;
 
-  constructor(bucketName: string) {
+  private constructor(bucketName: string) {
     this.bucketName = bucketName;
     this.s3Client = new S3Client({
       region: process.env.AWS_REGION,
@@ -18,6 +18,13 @@ export class S3Service {
     });
   }
 
+  static getInstance(bucketName: string): S3Service {
+    if (!S3Service.instance) {
+      S3Service.instance = new S3Service(bucketName);
+    }
+    return S3Service.instance;
+  }
+
   async uploadFile(
     key: string,
     body: Buffer | Readable,

src/app/server/services/integrations/texextract.service.ts

@@ -7,10 +7,12 @@ import {
 export const maxDuration = 60;
 
 export class TextractService {
+  private static instance: TextractService;
   private textractClient: TextractClient;
   private bucketName: string;
 
-  constructor(bucketName: string) {
+  // Private constructor to prevent direct instantiation
+  private constructor(bucketName: string) {
     this.bucketName = bucketName;
     this.textractClient = new TextractClient({
       region: process.env.AWS_REGION,
@@ -21,6 +23,14 @@ export class TextractService {
     });
   }
 
+  // Static method to get the singleton instance
+  public static getInstance(bucketName: string): TextractService {
+    if (!TextractService.instance) {
+      TextractService.instance = new TextractService(bucketName);
+    }
+    return TextractService.instance;
+  }
+
   public async extractTextFromS3PDF(objectKey: string): Promise<string> {
     try {
       // Start the Textract document text detection

src/app/server/services/questions.service.ts

@@ -4,7 +4,7 @@ import {
   Papers,
   QuestionsWithEverything,
 } from "@/app/lib/types/feed.types";
-import { prisma } from "../db/prisma";
+import { prisma } from "../utils/prisma";
 
 const DEFAULT_ANSWER_LIMIT = 5;
 const DEFAULT_QUESTIONS_OFFSET = 0;

src/app/server/services/topics.services.ts

@@ -1,4 +1,4 @@
-import { prisma } from "../db/prisma";
+import { prisma } from "../utils/prisma";
 
 export const getAllTopics = () => {
   return prisma.topics.findMany();

src/app/server/services/user.service.ts

@@ -1,4 +1,4 @@
-import { prisma } from "../db/prisma";
+import { prisma } from "../utils/prisma";
 
 export async function getUserByEmail(email: string) {
   const user = await prisma.user.findUnique({

src/app/server/db/prisma.ts renamed to src/app/server/utils/prisma.ts

@@ -1,6 +1,7 @@
 import { ErrorCodes } from "@/app/lib/constants";
 import { NextResponse } from "next/server";
 
+// TODO: Replace this with zod schema.
 export async function validateEvaluateAnswerAPIFormData(
   answerPDF: FormDataEntryValue | null,
   question?: string,