From 43abb6d5fd0202714b24ce674cb70194d45a6156 Mon Sep 17 00:00:00 2001
From: theoleuthardt <theoleuthardt12@gmail.com>
Date: Sun, 16 Feb 2025 17:52:08 +0100
Subject: [PATCH] feat: extended backend functionality for converting files to
 the selected file extension sent to the backend via api

---
 backend/server.ts                        |  2 +-
 backend/src/routes/libreconvert.route.ts | 57 +++++++++++++++++++-----
 2 files changed, 47 insertions(+), 12 deletions(-)

diff --git a/backend/server.ts b/backend/server.ts
index 03bb2e9..5156540 100644
--- a/backend/server.ts
+++ b/backend/server.ts
@@ -5,7 +5,7 @@ import { libreConvert } from "./src/routes/libreconvert.route";
 
 const app = Fastify({ logger: true });
 
-app.register(cors, { origin: "*" });
+app.register(cors, { origin: "*", exposedHeaders: 'Content-Disposition' });
 app.register(multipart);
 app.register(libreConvert);
 
diff --git a/backend/src/routes/libreconvert.route.ts b/backend/src/routes/libreconvert.route.ts
index ac4c8af..746be93 100644
--- a/backend/src/routes/libreconvert.route.ts
+++ b/backend/src/routes/libreconvert.route.ts
@@ -1,30 +1,65 @@
 import { FastifyInstance, FastifyReply, FastifyRequest } from "fastify";
 import * as libre from "libreoffice-convert";
 import { promisify } from "util";
+import { MultipartValue } from "@fastify/multipart";
 
 const libreConvertAsync = promisify(libre.convert);
 
+const mimeTypes: { [key: string]: string } = {
+  'pdf': 'application/pdf',
+  'html': 'text/html',
+  'doc': 'application/msword',
+  'docx': 'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
+  'txt': 'text/plain',
+  'rtf': 'application/rtf',
+  'odt': 'application/vnd.oasis.opendocument.text',
+  'xlsx': 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
+  'xls': 'application/vnd.ms-excel',
+  'ods': 'application/vnd.oasis.opendocument.spreadsheet',
+  'pptx': 'application/vnd.openxmlformats-officedocument.presentationml.presentation',
+  'ppt': 'application/vnd.ms-powerpoint',
+  'odp': 'application/vnd.oasis.opendocument.presentation'
+};
+
 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 parts = request.parts();
+
+      let fileBuffer: Buffer | null = null;
+      let outputFileExt = "";
+
+      for await (const part of parts) {
+        if (part.type === "file") {
+          fileBuffer = await part.toBuffer();
+        } else if (part.fieldname === "outputFormat" && part.type === "field") {
+          outputFileExt = (part as MultipartValue<string>).value;
+          console.log("Output format:", outputFileExt);
+        }
       }
 
-      const ext = ".pdf";
-      const format = ext.substring(1);
-      const fileBuffer = await data.toBuffer();
+      if (!fileBuffer) {
+        return reply.status(400).send({ error: "No file uploaded!" });
+      }
+      if (!outputFileExt) {
+        return reply.status(400).send({ error: "No output format provided!" });
+      }
+      if (!outputFileExt.startsWith(".")) {
+        outputFileExt = "." + outputFileExt;
+      }
 
-      const pdfBuffer = await libreConvertAsync(fileBuffer, ext, undefined);
+      const format = outputFileExt.substring(1);
+      const mimeType = mimeTypes[format] || 'application/octet-stream';
+
+      const convertedBuffer = await libreConvertAsync(fileBuffer, outputFileExt, undefined);
 
       reply
-          .header("Content-Type", "application/" + format)
-          .header("Content-Disposition", "attachment; filename=converted" + ext)
-          .send(pdfBuffer);
+          .header("Content-Type", mimeType)
+          .header("Content-Disposition", `attachment; filename="converted${outputFileExt}"`)
+          .send(convertedBuffer);
     } catch (error) {
       console.error("Convert error:", error);
       reply.status(500).send({ error: "Error while converting!" });
     }
   });
-}
+}
\ No newline at end of file