shinyapp 中的交互式文件输入和反应式阅读

Question

我想制作一个 shinyapp，它集成了选择文件（在选定文件夹中）的功能，（如 ), and then reading it reactively by detecting changes in it, as in https://gist.github.com/wch/9652222。

但是，我可以不让 reactiveFileReader 函数与反应文件名（文件夹）一起工作。它似乎只与一个预先确定的文件名一起工作。

在这个应用程序中，文件预计会在选择后自动选择任何文件夹（按钮），前提是它在里面并且与子文件夹同名且扩展名.csv
例如，如果选择/home/name/folder，则所选文件应为/home/name/folder/folder.csv
下面是没有预期功能的代码。它显示了一个示例文件。

server<- function(input, output, session) { 
  shinyDirChoose(input, 'dir', roots = c(home = path1) )
  reacdir <- reactive(input$dir)
  output$dirtext <- renderPrint(c(path(),current() ) )
  path1<-"~"
  path <- reactive({
    home <- normalizePath(path1)
    file.path(home, paste(unlist(reacdir()$path[-1]), collapse = .Platform$file.sep))
  })

  current<-reactive({
    a<-sub('.*\/', '', path() )  
    b<-paste("current subdir:",a)
  })

#  logfilename<- reactive({filename<-paste0(path(),"/",sub('.*\/', '', path() ),".csv")})
   logfilename <- paste0('logfile',
                         floor(runif(1, 1e+05, 1e+06 - 1)),".txt")
  #    

  logwriter <- observe({
    invalidateLater(1000, session)
    cat(as.character(Sys.time()), '\n', file = logfilename,
        append = TRUE)
  })

  fileReaderData <- reactiveFileReader(500, session,
                                       logfilename, readLines)
 # when using logfilename(): You tried to do something that can only be done from inside a reactive expression or observer.

  # Also not working: fileReaderData <- reactive({file<-reactiveFileReader(500, session,
  #                                       logfilename(), readLines) })

  output$fileReaderText <- renderText({
    text <- fileReaderData()
    length(text) <- 14
    text[is.na(text)] <- ""
    paste(text, collapse = '\n')
  })
}
ui<-fluidPage(
  titlePanel("interactive selection of file and reactive reading"),
  fluidRow(
    column(12,
           shinyDirButton("dir", "1. Choose directory", "Upload")
           ,br(),br(),
            p("This app has a log file which is appended to",
             "every second.")
    )
  ),
  fluidRow(
    column(6, wellPanel(
      verbatimTextOutput("fileReaderText")
    ))
  )
)

shinyApp(ui, server)

Answer 1

我想到了这个解决方案。已测试从外部修改 /folder/folder.csv 文件。

library(shiny)
library(shinyFiles)
path1<-"~"
server<- function(input, output, session) { 
  shinyDirChoose(input, 'dir', roots = c(home = path1) )
  reacdir <- reactive(input$dir)
  output$dirtext <- renderPrint(c(path(),current() ) )

  path <- reactive({
    home <- normalizePath(path1)
    file.path(home, paste(unlist(reacdir()$path[-1]), collapse = .Platform$file.sep))
  })

  current<-reactive({
    a<-sub('.*\/', '', path() )  
    b<-paste("current subdir:",a)
  })
  reac<-reactiveValues()
    observe({
        if(file.exists(paste0(path(),"/",sub('.*\/', '', path() ),".csv")) ){
      fileReaderData<-reactiveFileReader(1000, session, paste0(path(),"/",sub('.*\/', '', path() ),".csv"), read.csv, stringsAsFactors=FALSE)
      reac$df<-fileReaderData()
      output$fileReaderText <- renderText({
        text <- reac$df
        length(text) <- 14
        text[is.na(text)] <- ""
        paste(text, collapse = '\n')
    })
    }
    else{"index file does not exist, create with button 2."}
    }
  ) 
}
ui<-fluidPage(
  titlePanel("interactive selection of file and reactive reading"),
  fluidRow(
    column(12,
           shinyDirButton("dir", "1. Choose directory", "Upload")
           ,br(),br(),
           p("shinyapp")
    )
  ),
  fluidRow(
    column(6, wellPanel(
      verbatimTextOutput("fileReaderText")
    ))
  )
)

shinyApp(ui, server)

shinyapp 中的交互式文件输入和反应式阅读

Interactive file input and reactive reading in shinyapp

r

shiny

reactive