在R Shiny中阅读excel效果缓慢

Question

I have a shiny app, that is supposed to first pull/read the data from two excel file, then use reactive to customize the results of excel files to produce two tables. Problem is that excel files are heavy , and app takes a lot of time to read excel files. it also slows down the reactivity response time. Below is a dummy code that explain the structure of my app.

    library(readxl)

    ui <- fluidPage(

    tableOutput('dt1'),
    tableOutput('dt2'),
    selectInput('choice','TLT Select',choices= c('Yes','No'))

    )

    server <- shinyServer(function(input, output){

    t.1 a <-as.data.frame(read_excel(path ="A.xlsx") ,stringsAsFactors = FALSE) #this is a 45 MB excel file

    t.2 <- a <-as.data.frame(read_excel(path ="B.xlsx") ,stringsAsFactors = FALSE) # this is a 50 MB excel file

     excel.a <- reactive({

     if (input$choice == 'Yes') {
      subset(t.1, t.1$Action == 'Yes') }
      else 
      {subset(t.1, t.1$Action == 'No')}


     excel.b <- reactive({

     if (input$choice == 'Yes') {
      subset(t.2, t.2$Action == 'Yes') }
      else 
      {subset(t.2, t.2$Action == 'No')}


      output$dt1 <- renderTable({
      excel.1()
     })

      output$dt2 <- renderTable({
      excel.2()
     })

    })

    }

shinyApp(ui, server)

This is of course not a reproduce able example , but this is how my query is structured. Any idea how to make it more efficient and faster , so that it loads quickly and reactive response is more faster as well ?

Thanks

Answer 1

Try it in browser or add "browse" button. Add to server something like:

 data <- reactive({
    validate(
      need(input$file != "", "Please select a data set !!!\nUse 'Browse' bottom to choose\n")
    )

    inFile <- input$file
    if (is.null(inFile))
      return(NULL)
    a <-as.data.frame(read_excel(inFile$datapath) ,stringsAsFactors = FALSE) 
    ....... # all manipulation

# and in UI
fileInput("file", "Choose Date file:",accept = c('.xlsx')

May be this is not a file download time, may be it is time for representation data in HTML css etc format