feat(pkg-r): bookmark support

pkg-r/NEWS.md

@@ -1,5 +1,7 @@
 # querychat (development version)
 
+* Added bookmarking support to `QueryChat$server()` and `querychat_app()`. When bookmarking is enabled (via `bookmark_store = "url"` or `"server"` in `querychat_app()` or `$app_obj()`, or via `enable_bookmarking = TRUE` in `$server()`), the chat state (including current query, title, and chat history) will be saved and restored with Shiny bookmarks. (#107)
+
 * Nearly the entire functional API (i.e., `querychat_init()`, `querychat_sidebar()`, `querychat_server()`, etc) has been hard deprecated in favor of a simpler OOP-based API. Namely, the new `QueryChat$new()` class is now the main entry point (instead of `querychat_init()`) and has methods to replace old functions (e.g., `$sidebar()`, `$server()`, etc). (#109)
     * In addition, `querychat_data_source()` was renamed to `as_querychat_data_source()`, and remains exported for a developer extension point, but users no longer have to explicitly create a data source. (#109)
 

pkg-r/R/QueryChat.R

@@ -309,7 +309,9 @@ QueryChat <- R6::R6Class(
       }
 
       server <- function(input, output, session) {
-        qc_vals <- self$server()
+        # Enable bookmarking if bookmark_store is enabled
+        enable_bookmarking <- bookmark_store %in% c("url", "server")
+        qc_vals <- self$server(enable_bookmarking = enable_bookmarking)
 
         output$query_title <- shiny::renderText({
           if (shiny::isTruthy(qc_vals$title())) {
@@ -432,6 +434,12 @@ QueryChat <- R6::R6Class(
     #' the reactive logic for the chat interface and returns session-specific
     #' reactive values.
     #'
+    #' @param enable_bookmarking Whether to enable bookmarking for the chat
+    #'   state. Default is `FALSE`. When enabled, the chat state (including
+    #'   current query, title, and chat history) will be saved and restored
+    #'   with Shiny bookmarks. This requires that the Shiny app has bookmarking
+    #'   enabled via `shiny::enableBookmarking()` or the `enableBookmarking`
+    #'   parameter of `shiny::shinyApp()`.
     #' @param session The Shiny session object.
     #'
     #' @return A list containing session-specific reactive values and the chat
@@ -446,14 +454,17 @@ QueryChat <- R6::R6Class(
     #' qc <- QueryChat$new(mtcars, "mtcars")
     #'
     #' server <- function(input, output, session) {
-    #'   qc_vals <- qc$server()
+    #'   qc_vals <- qc$server(enable_bookmarking = TRUE)
     #'
     #'   output$data <- renderDataTable(qc_vals$df())
     #'   output$query <- renderText(qc_vals$sql())
     #'   output$title <- renderText(qc_vals$title() %||% "No Query")
     #' }
     #' }
-    server = function(session = shiny::getDefaultReactiveDomain()) {
+    server = function(
+      enable_bookmarking = FALSE,
+      session = shiny::getDefaultReactiveDomain()
+    ) {
       if (is.null(session)) {
         rlang::abort(
           "$server() must be called within a Shiny server function."
@@ -464,7 +475,8 @@ QueryChat <- R6::R6Class(
         self$id,
         data_source = private$.data_source,
         greeting = self$greeting,
-        client = private$.client
+        client = private$.client,
+        enable_bookmarking = enable_bookmarking
       )
     },
 

pkg-r/R/querychat_module.R

@@ -20,10 +20,17 @@ mod_ui <- function(id, ...) {
 }
 
 # Main module server function
-mod_server <- function(id, data_source, greeting, client) {
+mod_server <- function(
+  id,
+  data_source,
+  greeting,
+  client,
+  enable_bookmarking = FALSE
+) {
   shiny::moduleServer(id, function(input, output, session) {
     current_title <- shiny::reactiveVal(NULL, label = "current_title")
     current_query <- shiny::reactiveVal("", label = "current_query")
+    has_greeted <- shiny::reactiveVal(FALSE, label = "has_greeted")
     filtered_df <- shiny::reactive(label = "filtered_df", {
       execute_query(data_source, query = DBI::SQL(current_query()))
     })
@@ -56,20 +63,26 @@ mod_server <- function(id, data_source, greeting, client) {
     # Prepopulate the chat UI with a welcome message that appears to be from the
     # chat model (but is actually hard-coded). This is just for the user, not for
     # the chat model to see.
-    greeting_content <- if (!is.null(greeting) && any(nzchar(greeting))) {
-      greeting
-    } else {
-      # Generate greeting on the fly if none provided
-      rlang::warn(c(
-        "No greeting provided; generating one now. This adds latency and cost.",
-        "i" = "Consider using $generate_greeting() to create a reusable greeting."
-      ))
-      chat_temp <- client$clone()
-      prompt <- "Please give me a friendly greeting. Include a few sample prompts in a two-level bulleted list."
-      chat_temp$stream_async(prompt)
-    }
+    shiny::observe(label = "greet_on_startup", {
+      if (has_greeted()) {
+        return()
+      }
 
-    shinychat::chat_append("chat", greeting_content)
+      greeting_content <- if (!is.null(greeting) && any(nzchar(greeting))) {
+        greeting
+      } else {
+        # Generate greeting on the fly if none provided
+        rlang::warn(c(
+          "No greeting provided; generating one now. This adds latency and cost.",
+          "i" = "Consider using $generate_greeting() to create a reusable greeting."
+        ))
+        prompt <- "Please give me a friendly greeting. Include a few sample prompts in a two-level bulleted list."
+        chat$stream_async(prompt)
+      }
+
+      shinychat::chat_append("chat", greeting_content)
+      has_greeted(TRUE)
+    })
 
     append_stream_task <- shiny::ExtendedTask$new(
       function(client, user_input) {
@@ -94,6 +107,28 @@ mod_server <- function(id, data_source, greeting, client) {
       current_title(input$chat_update$title)
     })
 
+    if (enable_bookmarking) {
+      shinychat::chat_restore("chat", chat, session = session)
+
+      shiny::onBookmark(function(state) {
+        state$values$querychat_sql <- current_query()
+        state$values$querychat_title <- current_title()
+        state$values$querychat_has_greeted <- has_greeted()
+      })
+
+      shiny::onRestore(function(state) {
+        if (!is.null(state$values$querychat_sql)) {
+          current_query(state$values$querychat_sql)
+        }
+        if (!is.null(state$values$querychat_title)) {
+          current_title(state$values$querychat_title)
+        }
+        if (!is.null(state$values$querychat_has_greeted)) {
+          has_greeted(state$values$querychat_has_greeted)
+        }
+      })
+    }
+
     list(
       client = chat,
       sql = current_query,