如何为shinyWidgets的selectizeGroupUI实现输入值书签保存功能

开发R Shiny应用时，使用shinyWidgets包的selectizeGroupUI组件构建多维度用户筛选输入控件，启用Shiny书签功能保存应用状态时，该组件的用户选中值无法被正常存储，原有实现无法完成selectizeGroupUI的状态书签保存，可复现问题的示例代码如下：

library(shiny)
library(shinyWidgets)

data("mpg", package = "ggplot2")

ui <- function(request) {
   fluidPage(
      fluidRow(
         column(
            width = 10,
            offset = 1,
            bookmarkButton(),
            tags$h3("Filter data with selectize group"),
            panel(
               selectizeGroupUI(
                  id = "my-filters",
                  params = list(
                     manufacturer = list(inputId = "manufacturer", title = "Manufacturer:"),
                     model = list(inputId = "model", title = "Model:"),
                     trans = list(inputId = "trans", title = "Trans:"),
                     class = list(inputId = "class", title = "Class:")
                  )
               ), status = "primary"),
            DT::dataTableOutput(outputId = "table"))))
}

server <- function(input, output, session) {
   vals <- reactiveValues(sum = NULL)
   
   res_mod <- callModule(
      module = selectizeGroupServer,
      id = "my-filters",
      data = mpg,
      vars = c("manufacturer", "model", "trans", "class"))
   
   output$table <- DT::renderDataTable(res_mod())
   
   # 原有书签逻辑无法保存筛选值
   onBookmark(function(state) {
      state$values$filtered <- res_mod()
   })
   
   onRestore(function(state) {
      vals$sum <- state$values$filtered
   })
}

shinyApp(ui, server, enableBookmarking = "server")

selectizeGroupUI/selectizeGroupServer是shinyWidgets封装的模块组件，筛选值的联动逻辑全部在模块内部维护，不会自动被Shiny默认的书签采集逻辑捕获；原有代码仅存储了过滤后的最终数据集，没有存储每个筛选项的选中值，也没有在书签恢复时触发组件的回填更新逻辑，因此无法还原筛选状态。

核心处理逻辑分两步：

• 保存书签时，主动提取带模块命名空间的所有筛选框的实时选中值，存入书签字段
• 恢复书签时，等待组件初始化完成后，逐一把保存的选中值回填到对应筛选输入框，触发组件自带的联动筛选逻辑，自动还原过滤结果

修改后的可直接运行的代码如下：

library(shiny)
library(shinyWidgets)

data("mpg", package = "ggplot2")

ui <- function(request) {
  fluidPage(
    fluidRow(
      column(
        width = 10,
        offset = 1,
        bookmarkButton(),
        tags$h3("Filter data with selectize group"),
        panel(
          selectizeGroupUI(
            id = "my-filters",
            params = list(
              manufacturer = list(inputId = "manufacturer", title = "Manufacturer:"),
              model = list(inputId = "model", title = "Model:"),
              trans = list(inputId = "trans", title = "Trans:"),
              class = list(inputId = "class", title = "Class:")
            )
          ), status = "primary"),
        DT::dataTableOutput(outputId = "table"))))
}

server <- function(input, output, session) {
  res_mod <- callModule(
    module = selectizeGroupServer,
    id = "my-filters",
    data = mpg,
    vars = c("manufacturer", "model", "trans", "class")
  )
  
  output$table <- DT::renderDataTable(res_mod())
  
  # 保存书签时存储所有筛选项的选中值
  onBookmark(function(state) {
    # 模块命名空间为my-filters，内部输入ID格式为 模块ID-输入ID
    state$values$sel_manufacturer <- input[["my-filters-manufacturer"]]
    state$values$sel_model <- input[["my-filters-model"]]
    state$values$sel_trans <- input[["my-filters-trans"]]
    state$values$sel_class <- input[["my-filters-class"]]
  })
  
  # 恢复书签时回填选中值，onRestored会在应用初始状态加载完成后触发
  onRestored(function(state) {
    updateSelectizeInput(
      session,
      inputId = "my-filters-manufacturer",
      selected = state$values$sel_manufacturer
    )
    updateSelectizeInput(
      session,
      inputId = "my-filters-model",
      selected = state$values$sel_model
    )
    updateSelectizeInput(
      session,
      inputId = "my-filters-trans",
      selected = state$values$sel_trans
    )
    updateSelectizeInput(
      session,
      inputId = "my-filters-class",
      selected = state$values$sel_class
    )
  })
}

shinyApp(ui, server, enableBookmarking = "server")

注意：如果筛选维度更多，按相同规则追加对应输入值的存取逻辑即可，回填后组件会自动触发级联过滤，不需要手动处理过滤后的数据。

内容的提问来源于stack exchange，提问作者samir