feat: new separate frontend and backend folders with fastify as nodejs framework, libreconvert is configured in fastify as route

backend/package.json

@@ -0,0 +1,28 @@
+{
+  "name": "backend",
+  "version": "1.0.0",
+  "main": "server.ts",
+  "scripts": {
+    "dev": "ts-node server.ts",
+    "build": "tsc",
+    "start": "node dist/server.js"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "description": "",
+  "dependencies": {
+    "@fastify/cors": "^10.0.2",
+    "@fastify/multipart": "^9.0.3",
+    "dotenv": "^16.4.7",
+    "fastify": "^5.2.1",
+    "fastify-cors": "^6.0.3",
+    "fastify-multipart": "^5.3.1",
+    "libreoffice-convert": "^1.6.0"
+  },
+  "devDependencies": {
+    "@types/node": "^22.13.4",
+    "ts-node": "^10.9.2",
+    "typescript": "^5.7.3"
+  }
+}

backend/server.ts

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+import Fastify from "fastify";
+import cors from "@fastify/cors";
+import multipart from '@fastify/multipart';
+import { libreConvert } from "./src/routes/libreconvert.route";
+
+const app = Fastify({ logger: true });
+
+app.register(cors, { origin: "*" });
+app.register(multipart);
+app.register(libreConvert);
+
+const PORT = process.env.PORT || 4000;
+app.listen({ port: Number(PORT), host: "0.0.0.0" }, () => {
+    console.log(`🚀Fastify is live on http://localhost:${PORT}`);
+});

backend/src/routes/libreconvert.route.ts

@@ -0,0 +1,30 @@
+import { FastifyInstance, FastifyReply, FastifyRequest } from "fastify";
+import * as libre from "libreoffice-convert";
+import { promisify } from "util";
+
+const libreConvertAsync = promisify(libre.convert);
+
+export async function libreConvert(app: FastifyInstance) {
+  app.post("/api/libre-convert", async (request: FastifyRequest, reply: FastifyReply) => {
+    try {
+      const data = await request.file();
+      if (!data) {
+        return reply.status(400).send({ error: "No file uploaded!" });
+      }
+
+      const ext = ".pdf";
+      const format = ext.substring(1);
+      const fileBuffer = await data.toBuffer();
+
+      const pdfBuffer = await libreConvertAsync(fileBuffer, ext, undefined);
+
+      reply
+          .header("Content-Type", "application/" + format)
+          .header("Content-Disposition", "attachment; filename=converted" + ext)
+          .send(pdfBuffer);
+    } catch (error) {
+      console.error("Convert error:", error);
+      reply.status(500).send({ error: "Error while converting!" });
+    }
+  });
+}

backend/tsconfig.json

@@ -0,0 +1,10 @@
+{
+  "compilerOptions": {
+    "target": "ES6",
+    "module": "CommonJS",
+    "outDir": "./dist",
+    "rootDir": "./src",
+    "strict": true,
+    "allowSyntheticDefaultImports": true
+  }
+}