Update app.py

app.py

@@ -50,4 +50,14 @@ if st.session_state.messages[-1]["role"] != "assistant":
             response = chat_engine.chat(prompt)
             st.write(response.response)
             message = {"role": "assistant", "content": response.response}
-            st.session_state.messages.append(message) # Add response to message history
+            st.session_state.messages.append(message) # Add response to message history
+
+try:
+    if prompt := st.chat_input("Your question"): # Prompt for user input and save to chat history
+        if not openai_api_key.startswith('sk-'):
+            st.warning('Please enter your OpenAI API key!', icon='⚠')
+        else: # Only allow the user to proceed if it appears they've entered a valid OpenAI API key
+            st.session_state.messages.append({"role": "user", "content": prompt})
+            # ... (rest of the code)
+except Exception as e:
+    st.error(f"An error occurred: {e}")