[Feature]: ui.Chat bookmark support

[schloerke]

Category

UI Components

Scope

Minor Enhancement

Problem

Chat doesn't restore from bookmarked state. It'd be nice to have this feature!

Solution

It should store information in the bookmark state (values?)

Last chat input value should be ignored.

Related R implementation: posit-dev/shinychat#28

Alternatives (Optional)

No response

Example (Optional)

Impact (Optional)

No response

Contribution? (Optional)

Yes, I can implement (or help).

[schloerke]

After talking with @cpsievert ...

chat_client = chatlas.ChatOpenAI(model="gpt-4o-mini")

# Create and display a Shiny chat component
chat = ui.Chat(
    id="chat",
    messages=[
        {"role": "assistant", "content": "Hello! How can I help you today?"}
    ],
)
chat.ui()


chat.enable_bookmarking(
    client=chat_client,
    # ONLY for ChatExpress. For core Chat, use the `App` directly
    bookmark_store="url",
)

chat.enable_bookmarking() TODOs

• Exclude the chat user input from bookmarking
• Add a on_bookmark hook
• Add a on_restore hook
• Adjust default messages to be ignored if restoration occurs.
• For express mode only, add parameter bookmark_store: BookmarkStore to reduce code burden in express mode
• Add a parameter for "on session disconnect, update the query string" as a last-ditch-effort to save the chat state; On restore of this state, reset the query string if there was no query string before the last-ditch-effort.
• Do NOT: register on_bookmarked to update query string automatically
• Do NOT: register effect to bookmark when .messages() updates. This should be done through templating to give Authors freedom