Update app.py

app.py

@@ -15,10 +15,12 @@ upload_success = False
 def upload_pdf(file):
     global upload_success
     filename = os.path.basename(file.name)
-    response = requests.post(PRESIGN_API_URL, json={
+    content_type = "application/pdf"
+    response = requests.post(url=PRESIGN_API_URL, json={
         "filename": filename,
         "user_id": user_id,
-        "session_id": session_id
+        "session_id": session_id,
+        "contentType": content_type
     })   
     if response.status_code != 200:
         return "❌ Failed to get presigned URL"