werkzeugkiste/backend/src/routes/libreconvert.route.ts

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!" });
    }
  });
}