Update app.py

app.py

@@ -55,7 +55,6 @@ def process_file(file_path):
 async def start():
     await cl.Message("👋 Welcome! Please upload a PDF to get started.").send()
 
-    # Let user upload file
     msg = await cl.AskFileMessage(
         content="📄 Upload your PDF file here:",
         accept=["application/pdf"],
@@ -67,10 +66,11 @@ async def start():
         file = msg.files[0]
         qa_chain = process_file(file.path)
 
-        # Save QA chain to session
         cl.user_session.set("qa_chain", qa_chain)
         cl.user_session.set("ready", True)
         await cl.Message(f"✅ File `{file.name}` processed. You can now ask your questions.").send()
+    else:
+        await cl.Message("❌ No file was uploaded. Please try again.").send()
 
 # On user message
 @cl.on_message
@@ -80,6 +80,9 @@ async def handle_message(message: cl.Message):
         return
 
     qa_chain = cl.user_session.get("qa_chain")
-    response = qa_chain(message.content)
-    answer = response["result"]
-    await cl.Message(content=answer).send()
+    try:
+        response = qa_chain(message.content)
+        answer = response["result"]
+        await cl.Message(content=answer).send()
+    except Exception as e:
+        await cl.Message(content=f"❌ An error occurred while generating a response: {str(e)}").send()