Update app.py

app.py

@@ -1,31 +1,63 @@
-from shiny import App, ui
+# ------------------------------------------------------------------------------------
+# A simple recipe extractor chatbot that extracts recipes from URLs using the OpenAI API.
+# To run it, you'll need an OpenAI API key.
+# To get one, follow the instructions at https://platform.openai.com/docs/quickstart
+# ------------------------------------------------------------------------------------
+import os
 
-app_ui = ui.page_fillable(
-    ui.panel_title("Hello Shiny Chat"),
-    ui.chat_ui("chat"),
+from openai import AsyncOpenAI
+from utils import recipe_prompt, scrape_page_with_url
+
+from shiny.express import ui
+
+# Provide your API key here (or set the environment variable)
+llm = AsyncOpenAI(api_key=os.environ.get("OPENAI_API_KEY"))
+
+# Set some Shiny page options
+ui.page_opts(
+    title="Recipe Extractor Chat",
+    fillable=True,
     fillable_mobile=True,
 )
 
-# Create a welcome message
-welcome = ui.markdown(
-    """
-    Hi! This is a simple Shiny `Chat` UI. Enter a message below and I will
-    simply repeat it back to you. For more examples, see this
-    [folder of examples](https://github.com/posit-dev/py-shiny/tree/main/examples/chat).
-    """
+# Initialize the chat (with a system prompt and starting message)
+chat = ui.Chat(
+    id="chat",
+    messages=[
+        {"role": "system", "content": recipe_prompt},
+        {
+            "role": "assistant",
+            "content": "Hello! I'm a recipe extractor. Please enter a URL to a recipe page. For example, <https://www.thechunkychef.com/epic-dry-rubbed-baked-chicken-wings/>",
+        },
+    ],
 )
 
+chat.ui(placeholder="Enter a recipe URL...")
+
+
+# A function to transform user input
+# Note that, if an exception occurs, the function will return a message to the user
+# "short-circuiting" the conversation and asking the user to try again.
+@chat.transform_user_input
+async def try_scrape_page(input: str) -> str | None:
+    try:
+        return await scrape_page_with_url(input)
+    except Exception:
+        await chat.append_message(
+            "I'm sorry, I couldn't extract content from that URL. Please try again. "
+        )
+        return None
 
-def server(input, output, session):
-    chat = ui.Chat(id="chat", messages=[welcome])
 
-    # Define a callback to run when the user submits a message
-    @chat.on_user_submit
-    async def _():
-        # Get the user's input
-        user = chat.user_input()
-        # Append a response to the chat
-        await chat.append_message(f"You said: {user}")
+@chat.on_user_submit
+async def _():
+    response = await llm.chat.completions.create(
+        model="gpt-4o",
+        messages=chat.messages(format="openai"),
+        temperature=0,
+        stream=True,
+    )
+    await chat.append_message_stream(response)
 
 
 app = App(app_ui, server)