如何从服务器/用户界面外部访问存储在 server.R 中的数据

Question

我对 R/Rshiny/RMarkdown 很陌生，我已经使用了一些基本的用户输入模板来构建应用程序。我想要的是用户输入文件路径并能够在另一个函数/块中调用文件名和文件路径。

我发现响应式可能是执行此操作的关键功能，但我不确定如何使用它。

library(shinyFiles)


  ui <- fluidPage(
    shinyFilesButton("Btn_GetFile", "Choose a file" ,
                                    title = "Please select a file:", multiple = TRUE,
                          buttonType = "default", class = NULL),

              textOutput("filename"), 
              textOutput("txt_file")
                   )

  filepath <- reactiveValues() #trying, but this isn't quite working
  server <- function(input,output,session){

    volumes = getVolumes()
    observe({  
    shinyFileChoose(input, "Btn_GetFile", roots = volumes, session = session)

    if(!is.null(input$Btn_GetFile)){
      # browser()
      file_selected<-parseFilePaths(volumes, input$Btn_GetFile)
      output$txt_file <- renderText(as.character(file_selected$datapath))
      output$filename <- renderText(as.character(file_selected$name))
      filepath <- reactive({output$txt_file}) #an attempt, but it isn't doing what I want.
    }
  })
  }

  shinyApp(ui = ui, server = server)
  isolate(filepath) #also tried print. Really just trying to see if filepath is populated

如果用户输入 /Users/Jim/tmp.txt，我希望看到 UI 显示 /Users/Jim/tmp.txt 和 tmp.txt（它确实如此）并且还看到 /Users/Jim/ tmp.txt 被存储为我可以在其他地方访问的文件路径变量。

Answer 1

看看?reactiveValues。修改了您的代码，这应该可以工作： 编辑根据您的评论，您可以尝试将system() 命令与glue 包结合使用

library(shinyFiles)
library(glue)

ui <- fluidPage(
  shinyFilesButton("Btn_GetFile", "Choose a file" ,
                   title = "Please select a file:", multiple = TRUE,
                   buttonType = "default", class = NULL),

  textOutput("filename"), 
  textOutput("txt_file")
)

rvs <- reactiveValues() #renamed to rvs
server <- function(input,output,session){

  volumes = getVolumes()
  observe({  
    shinyFileChoose(input, "Btn_GetFile", roots = volumes, session = session)

    req(input$Btn_GetFile)

    file_selected <- parseFilePaths(volumes, input$Btn_GetFile)
    output$txt_file <- renderText(as.character(file_selected$datapath))
    output$filename <- renderText(as.character(file_selected$name))
    rvs$filepath <- as.character(file_selected$datapath)
    print(rvs$filepath) #Added this print to test

  })
}
observe({
  req(rvs$filepath)
  system(glue("echo {rvs$filepath}"))
})
shinyApp(ui = ui, server = server)