Refactor PDF extraction to use chunked upload to bypass proxy size limits

backend/server.js

@@ -323,16 +323,25 @@ const getKeysFromProfile = async (userId) => {
 };
 
 // 1. Extract PDF (Gemini)
-app.post('/api/sparkplug/extract', authenticate, upload.single('file'), async (req, res) => {
-  if (!req.file) return res.status(400).json({ error: 'No file uploaded' });
+app.post('/api/sparkplug/extract', authenticate, async (req, res) => {
+  const { fileUrl } = req.body;
+  if (!fileUrl) return res.status(400).json({ error: 'No fileUrl provided' });
   
   try {
     const keys = await getKeysFromProfile(req.user.id);
     const geminiKey = keys.GEMINI_API_KEY;
     if (!geminiKey) return res.status(400).json({ error: 'Gemini API key missing' });
 
-    // Parse PDF
-    const dataBuffer = fs.readFileSync(req.file.path);
+    // Read PDF from the local file system
+    // fileUrl is something like '/uploads/1788251962641-55866782-file.pdf'
+    const fileName = fileUrl.replace('/uploads/', '');
+    const localFilePath = path.join(uploadsDir, fileName);
+
+    if (!fs.existsSync(localFilePath)) {
+      return res.status(404).json({ error: 'File not found on server' });
+    }
+
+    const dataBuffer = fs.readFileSync(localFilePath);
     const base64Pdf = dataBuffer.toString('base64');
 
     // Call Gemini to extract prompt
@@ -364,8 +373,12 @@ app.post('/api/sparkplug/extract', authenticate, upload.single('file'), async (r
   } catch (err) {
     res.status(500).json({ error: err.message });
   } finally {
-    if (req.file) {
-      fs.unlinkSync(req.file.path); // cleanup uploaded PDF
+    if (fileUrl) {
+      const fileName = fileUrl.replace('/uploads/', '');
+      const localFilePath = path.join(uploadsDir, fileName);
+      if (fs.existsSync(localFilePath)) {
+        fs.unlinkSync(localFilePath); // cleanup uploaded PDF
+      }
     }
   }
 });