Ressurect the hello starter template as an api-example (for API reference)

Author: cpsievert

shiny/api-examples/Chat/_template.json

@@ -0,0 +1,8 @@
+{
+  "type": "app",
+  "id": "chat-hello",
+  "title": "Hello Shiny Chat",
+  "next_steps": [
+    "Run the app with `shiny run app.py`."
+  ]
+}

shiny/api-examples/Chat/app-core.py

@@ -0,0 +1,29 @@
+from shiny import App, ui
+
+app_ui = ui.page_fillable(
+    ui.panel_title("Hello Shiny Chat"),
+    ui.chat_ui("chat"),
+    fillable_mobile=True,
+)
+
+# Create a welcome message
+welcome = """
+Hi! This is a simple Shiny `Chat` UI. Enter a message below and I will
+simply repeat it back to you.
+
+To learn more about chatbots and how to build them with Shiny, check out
+[the documentation](https://shiny.posit.co/py/docs/genai-chatbots.html).
+"""
+
+
+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 handle_user_input(user_input: str):
+        # Append a response to the chat
+        await chat.append_message(f"You said: {user_input}")
+
+
+app = App(app_ui, server)

shiny/api-examples/Chat/app-express.py

@@ -0,0 +1,33 @@
+from shiny.express import ui
+
+# Set some Shiny page options
+ui.page_opts(
+    title="Hello Shiny Chat",
+    fillable=True,
+    fillable_mobile=True,
+)
+
+# Create a welcome message
+welcome = """
+Hi! This is a simple Shiny `Chat` UI. Enter a message below and I will
+simply repeat it back to you.
+
+To learn more about chatbots and how to build them with Shiny, check out
+[the documentation](https://shiny.posit.co/py/docs/genai-chatbots.html).
+"""
+
+# Create a chat instance
+chat = ui.Chat(
+    id="chat",
+    messages=[welcome],
+)
+
+# Display it
+chat.ui()
+
+
+# Define a callback to run when the user submits a message
+@chat.on_user_submit
+async def handle_user_input(user_input: str):
+    # Append a response to the chat
+    await chat.append_message(f"You said: {user_input}")

shiny/api-examples/Chat/requirements.txt

@@ -0,0 +1 @@
+shiny

shiny/ui/_chat.py

@@ -90,7 +90,7 @@
 ]
 
 
-@add_example(ex_dir="../templates/chat/starters/hello")
+@add_example("app-core.py")
 class Chat:
     """
     Create a chat interface.
@@ -1326,7 +1326,7 @@ async def _send_custom_message(self, handler: str, obj: ClientMessage | None):
         )
 
 
-@add_example(ex_dir="../templates/chat/starters/hello")
+@add_example("app-express.py")
 class ChatExpress(Chat):
     def ui(
         self,
@@ -1377,7 +1377,7 @@ def ui(
         )
 
 
-@add_example(ex_dir="../templates/chat/starters/hello")
+@add_example(ex_dir="../api-examples/Chat")
 def chat_ui(
     id: str,
     *,