Fix Gradio Chatbot format compatibility: convert dict to tuple format for 4.20.0

app.py

@@ -39,6 +39,78 @@ def can_view_analytics(role: str) -> bool:
     return role in VALID_ROLES  # All roles can view analytics
 
 
+def convert_history_to_tuples(history):
+    """
+    Convert history from dict format to tuple format for Gradio 4.20.0 compatibility.
+    
+    Input format: [{"role": "user", "content": "..."}, {"role": "assistant", "content": "..."}]
+    Output format: [("user message", "assistant response"), ...]
+    """
+    if not history:
+        return []
+    
+    # If already in tuple format, return as-is
+    if history and isinstance(history[0], (tuple, list)) and len(history[0]) == 2:
+        return history
+    
+    # Convert dict format to tuple format
+    result = []
+    current_user = None
+    current_assistant = None
+    
+    for item in history:
+        if isinstance(item, dict):
+            if item.get("role") == "user":
+                # If we have a pending assistant message, save the pair
+                if current_user is not None and current_assistant is not None:
+                    result.append((current_user, current_assistant))
+                current_user = item.get("content", "")
+                current_assistant = None
+            elif item.get("role") == "assistant":
+                current_assistant = item.get("content", "")
+        elif isinstance(item, (tuple, list)) and len(item) == 2:
+            # Already in tuple format
+            result.append(tuple(item))
+    
+    # Add the last pair if exists
+    if current_user is not None:
+        result.append((current_user, current_assistant or ""))
+    
+    return result
+
+
+def append_to_history(history, role, content):
+    """
+    Append a message to history in tuple format for Gradio 4.20.0.
+    """
+    history = convert_history_to_tuples(history)
+    
+    if role == "user":
+        # For user messages, we need to add a new tuple with empty assistant response
+        history.append((content, ""))
+    elif role == "assistant":
+        # For assistant messages, update the last tuple's assistant part
+        if history and len(history[-1]) == 2:
+            user_msg = history[-1][0]
+            history[-1] = (user_msg, content)
+        else:
+            # If no user message exists, create one with empty user
+            history.append(("", content))
+    
+    return history
+
+
+def update_last_assistant_message(history, content):
+    """
+    Update the last assistant message in history (tuple format).
+    """
+    history = convert_history_to_tuples(history)
+    if history and len(history[-1]) == 2:
+        user_msg = history[-1][0]
+        history[-1] = (user_msg, content)
+    return history
+
+
 def chat_with_agent(message, tenant_id, role, history):
     """
     Send a message to the backend MCP agent and return the response.
@@ -58,19 +130,22 @@ def chat_with_agent(message, tenant_id, role, history):
     Yields:
         Updated chat history with agent response (streaming character-by-character)
     """
+    # Convert history to tuple format for Gradio 4.20.0 compatibility
+    history = convert_history_to_tuples(history)
+    
     if not message or not message.strip():
         yield history
         return
     
     if not tenant_id or not tenant_id.strip():
         error_msg = "Please enter a Tenant ID before sending a message."
-        history.append({"role": "user", "content": message})
-        history.append({"role": "assistant", "content": error_msg})
+        history = append_to_history(history, "user", message)
+        history = append_to_history(history, "assistant", error_msg)
         yield history
         return
     
     # Add user message to history
-    history.append({"role": "user", "content": message})
+    history = append_to_history(history, "user", message)
     
     # Backend streaming endpoint
     backend_url = f"{BACKEND_BASE_URL}/agent/message/stream"
@@ -104,7 +179,7 @@ def chat_with_agent(message, tenant_id, role, history):
         if response.status_code == 200:
             # Initialize assistant message
             assistant_message = ""
-            history.append({"role": "assistant", "content": assistant_message})
+            history = append_to_history(history, "assistant", assistant_message)
             yield history  # Yield initial empty message
             
             # Stream tokens character-by-character for smooth UX
@@ -126,7 +201,7 @@ def chat_with_agent(message, tenant_id, role, history):
                                     status_msg = data.get('message', '')
                                     if status_msg:
                                         # Show status in the message temporarily
-                                        history[-1] = {"role": "assistant", "content": f"⏳ {status_msg}"}
+                                        history = update_last_assistant_message(history, f"⏳ {status_msg}")
                                         yield history
                                     continue
                                 
@@ -135,7 +210,7 @@ def chat_with_agent(message, tenant_id, role, history):
                                 if token:
                                     assistant_message += token
                                     # Update the last message in history
-                                    history[-1] = {"role": "assistant", "content": assistant_message}
+                                    history = update_last_assistant_message(history, assistant_message)
                                     yield history  # Yield updated history immediately for smooth character-by-character display
                                 
                                 if data.get('done', False):
@@ -146,7 +221,7 @@ def chat_with_agent(message, tenant_id, role, history):
                             try:
                                 error_data = json.loads(line[6:])
                                 error_msg = error_data.get('error', 'Unknown error')
-                                history[-1] = {"role": "assistant", "content": f"❌ Error: {error_msg}"}
+                                history = update_last_assistant_message(history, f"❌ Error: {error_msg}")
                                 yield history
                                 break
                             except:
@@ -155,27 +230,27 @@ def chat_with_agent(message, tenant_id, role, history):
                         continue
         else:
             error_msg = f"Error {response.status_code}: {response.text}"
-            history.append({"role": "assistant", "content": error_msg})
+            history = append_to_history(history, "assistant", error_msg)
             yield history
     
     except requests.exceptions.ConnectionError:
         error_msg = "❌ Connection Error: Could not connect to backend. Please ensure the FastAPI server is running at http://localhost:8000"
-        history.append({"role": "assistant", "content": error_msg})
+        history = append_to_history(history, "assistant", error_msg)
         yield history
     
     except requests.exceptions.Timeout:
         error_msg = "⏱️ Request Timeout: The backend took longer than 2 minutes to respond. This may happen if:\n- The LLM is processing a complex query\n- Multiple tools (RAG, Web Search) are being used\n- The backend is under heavy load\n\nPlease try again with a simpler query, or check if the backend services (Ollama, MCP servers) are running properly."
-        history.append({"role": "assistant", "content": error_msg})
+        history = append_to_history(history, "assistant", error_msg)
         yield history
     
     except requests.exceptions.RequestException as e:
         error_msg = f"❌ Request Error: {str(e)}"
-        history.append({"role": "assistant", "content": error_msg})
+        history = append_to_history(history, "assistant", error_msg)
         yield history
     
     except Exception as e:
         error_msg = f"❌ Unexpected Error: {str(e)}"
-        history.append({"role": "assistant", "content": error_msg})
+        history = append_to_history(history, "assistant", error_msg)
         yield history
 
 
@@ -1869,7 +1944,8 @@ with gr.Blocks(
                 except Exception as e:
                     # Fallback if streaming fails
                     error_msg = f"Streaming error: {str(e)}"
-                    history.append({"role": "assistant", "content": error_msg})
+                    history = convert_history_to_tuples(history)
+                    history = append_to_history(history, "assistant", error_msg)
                     yield history, message_input_value
             
             send_button.click(