refactor: refactored 3 api endpoints to seperate logic between controller and services

Author: Gslmao

src/app/api/course-list/route.ts

@@ -1,14 +1,11 @@
 import { NextResponse } from "next/server";
-import { connectToDatabase } from "@/lib/database/mongoose";
-import { Course } from "@/db/course";
+import { getCourseList } from "@/lib/services/subject";
 
 export const dynamic = "force-dynamic";
 
 export async function GET() {
   try {
-    await connectToDatabase();
-    const courses = await Course.find().lean();
-
+    const courses = await getCourseList();
     return NextResponse.json(courses, { status: 200 });
   } catch (error) {
     console.error(error);

src/app/api/paper-by-id/[id]/route.ts

@@ -1,23 +1,16 @@
 import { NextResponse } from "next/server";
-import { connectToDatabase } from "@/lib/database/mongoose";
-import Paper from "@/db/papers";
 import { Types } from "mongoose";
+import { getPaperById } from "@/lib/services/paper";
 
 export async function GET(req: Request, { params }: { params: { id: string } }) {
   try {
-    await connectToDatabase();
-
     const { id } = params;
-
+    
     if (!Types.ObjectId.isValid(id)) {
       return NextResponse.json({ message: "Invalid paper ID" }, { status: 400 });
     }
 
-    const paper = await Paper.findById(id);
-
-    if (!paper) {
-      return NextResponse.json({ message: "Paper not found" }, { status: 404 });
-    }
+    const paper = await getPaperById(id);
 
     return NextResponse.json(paper, { status: 200 });
   } catch (error) {

src/app/api/papers/count/route.ts

@@ -1,21 +1,13 @@
 import { NextResponse } from "next/server";
-import { connectToDatabase } from "@/lib/database/mongoose";
-import CourseCount from "@/db/course";
+import { getCourseCounts } from "@/lib/services/paper";
 
 export const dynamic = "force-dynamic";
 
 export async function GET(req: Request) {
   try {
-    await connectToDatabase();
+    const courseCount = await getCourseCounts();
 
-    const count = await CourseCount.find().lean();
-
-    const formatted = count.map((item) => ({
-      name: item.name,
-      count: item.count,
-    }));
-
-    return NextResponse.json(formatted, { status: 200 });
+    return NextResponse.json(courseCount, { status: 200 });
   } catch (error) {
     return NextResponse.json(
       { message: "Failed to fetch course counts", error },

src/lib/services/paper.ts

@@ -3,24 +3,48 @@ import { type IPaper } from "@/interface";
 import { escapeRegExp } from "@/lib/utils/regex";
 import { extractUniqueValues } from "@/lib/utils/paper-aggregation";
 import { connectToDatabase } from "../database/mongoose";
+import CourseCount from "@/db/course";
 
 export async function getPapersBySubject(subject: string) {
-    if (!subject){
-        throw new Error("Subject query parameter is required");
-    }
+	if (!subject){
+		throw new Error("Subject query parameter is required");
+	}
+	await connectToDatabase();
+	
+	const escapedSubject = escapeRegExp(subject);
+	const papers: IPaper[] = await Paper.find({
+		subject: { $regex: new RegExp(`${escapedSubject}`, "i") },
+	});
 
-    await connectToDatabase();
-    
-    const escapedSubject = escapeRegExp(subject);
-    const papers: IPaper[] = await Paper.find({
-        subject: { $regex: new RegExp(`${escapedSubject}`, "i") },
-    });
+	const uniqueValues = extractUniqueValues(papers);
 
-    const uniqueValues = extractUniqueValues(papers);
+	return {
+		papers,
+		...uniqueValues,
+	}
 
-    return {
-        papers,
-        ...uniqueValues,
-    }
+}
 
+export async function getPaperById(id: string) {
+	await connectToDatabase();
+	const paper = await Paper.findById(id);
+
+	if (!paper) {
+		throw new Error("Paper not found"); // 404
+	}
+
+	return paper;
+}
+
+export async function getCourseCounts(){
+	await connectToDatabase();
+
+	const count = await CourseCount.find().lean();
+
+	const formatted = count.map((item) => ({
+		name: item.name,
+		count: item.count,
+	}));
+
+	return formatted;
 }

src/lib/services/subject.ts

@@ -0,0 +1,7 @@
+import { connectToDatabase } from "@/lib/database/mongoose";
+import { Course } from "@/db/course";
+
+export async function getCourseList(){
+	await connectToDatabase();
+	return await Course.find().lean();
+}