Create app.py

app.py

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+import os
+import gradio as gr
+from gradio import ChatMessage
+import requests
+from typing import Dict, List
+from langchain_core.messages import HumanMessage
+from langchain_core.tools import tool
+from langchain_openai import ChatOpenAI
+from langgraph.checkpoint.memory import MemorySaver
+from langgraph.prebuilt import create_react_agent
+
+# Weather and location tools
+@tool
+def get_lat_lng(location_description: str) -> dict[str, float]:
+    """Get the latitude and longitude of a location."""
+    return {"lat": 51.1, "lng": -0.1}  # London coordinates as dummy response
+
+@tool
+def get_weather(lat: float, lng: float) -> dict[str, str]:
+    """Get the weather at a location."""
+    return {"temperature": "21°C", "description": "Sunny"}  # Dummy response
+        
+
+def stream_from_agent(message: str, history: List[Dict[str, str]]) -> gr.ChatMessage:
+    """Process messages through the LangChain agent with visible reasoning."""
+    
+    # Initialize the agent
+    llm = ChatOpenAI(temperature=0, model="gpt-4")
+    memory = MemorySaver()
+    tools = [get_lat_lng, get_weather]
+    agent_executor = create_react_agent(llm, tools, checkpointer=memory)
+    
+    # Add message to history
+    past_messages = [HumanMessage(content=message)]
+    for h in history:
+        if h["role"] == "user":
+            past_messages.append(HumanMessage(content=h["content"]))
+    
+    messages_to_display = []
+    final_response = None
+    
+    for chunk in agent_executor.stream(
+        {"messages": past_messages},
+        config={"configurable": {"thread_id": "abc123"}}
+    ):
+        # Handle agent's actions and tool usage
+        if chunk.get("agent"):
+            for msg in chunk["agent"]["messages"]:
+                if msg.content:
+                    final_response = msg.content
+                
+                # Handle tool calls
+                for tool_call in msg.tool_calls:
+                    tool_message = ChatMessage(
+                        content=f"Parameters: {tool_call['args']}",
+                        metadata={
+                            "title": f"🛠️ Using {tool_call['name']}",
+                            "id": tool_call["id"],
+                            }
+                    )
+                    messages_to_display.append(tool_message)
+                    yield messages_to_display
+                    
+        # Handle tool responses
+        if chunk.get("tools"):
+            for tool_response in chunk["tools"]["messages"]:
+                # Find the corresponding tool message
+                for msg in messages_to_display:
+                    if msg.metadata.get("id") == tool_response.tool_call_id:
+                        msg.content += f"\nResult: {tool_response.content}"
+                        yield messages_to_display
+    
+    # Add the final response as a regular message
+    if final_response:
+        messages_to_display.append(ChatMessage(content=final_response))
+        yield messages_to_display
+
+# Create the Gradio interface
+demo = gr.ChatInterface(
+    fn=stream_from_agent,
+    type="messages",
+    title="🌤️ Weather Assistant",
+    description="Ask about the weather anywhere! Watch as I gather the information step by step.",
+    examples=[
+        "What's the weather like in Tokyo?",
+        "Is it sunny in Paris right now?",
+        "Should I bring an umbrella in New York today?"
+    ],
+
+)
+
+demo.launch()