Question

当我下载报告时，它始终是PDF版本。我已经分别对每个人进行了测试，他们的工作因此问题来自于切换，但问题是我尝试了一些事情并且没有任何作用我不明白为什么。

这是我的代码：

library(rmarkdown)

ui <- fluidPage(
  selectInput("algo", "Selection de l'agorithme utilise pour la simulation:", choice = list("algo1", "algo2")),
  radioButtons('format', 'Document format', c('PDF', 'HTML', 'Word'), inline = TRUE),
  downloadButton("report", "Generate report")
)



server <- function(input, output, session) {
  output$report <- downloadHandler(
    filename = switch(input$format,
                      "Word" = function() {
                        paste("reportHtml-", Sys.Date(), ".docx", sep="")
                      }, 
                      "PDF" = function() {
                        paste("reportPDF-", Sys.Date(), ".pdf", sep="")
                      },
                      "Word" = function() {
                        paste("reportHtml-", Sys.Date(), ".html", sep="")
                      }
    ),

    content =  switch(input$format,
                      "Word" = function(file1) {

                        report <- file.path("C:/R_sources/test/reportWord.Rmd")
                        params <- list(n = input$algo)
                        rmarkdown::render(report, output_file = file1,
                                          params = params,
                                          envir = new.env(parent = globalenv())
                        )
                      },

                      "PDF" = function(file2) {

                        report <- file.path("C:/R_sources/test/reportPdf.Rmd")
                        params <- list(n = input$algo)
                        rmarkdown::render(report, output_file = file2,
                                          params = params,
                                          envir = new.env(parent = globalenv())
                        )
                      },

                      "Word" = function(file3) {

                        report <- file.path("C:/R_sources/test/reportWord.Rmd")
                        params <- list(n = input$algo)
                        rmarkdown::render(report, output_file = file3,
                                          params = params,
                                          envir = new.env(parent = globalenv())
                        )
                      }
    )
  )
}

shinyApp(ui, server)

Answer 1

来自https://shiny.rstudio.com/reference/shiny/1.0.5/downloadHandler.html，

filename：文件名的字符串...或返回此类字符串的函数。（可以从此功能使用反应值和功能。）

因此，您应该将函数传递给filename参数。

代码中发生的事情是downloadHelper被评估并在加载时运行，此时input$format设置为＆＃34; PDF＆＃34;因为这是初始值。因此，对switch语句进行评估，filename始终绑定了PDF函数。

您应该做的是设置一个函数，并在其中使用switch语句。同样适用于content。所以它应该是这样的：

library(rmarkdown)

ui <- fluidPage(
  selectInput("algo", "Selection de l'agorithme utilise pour la simulation:", choice = list("algo1", "algo2")),
  radioButtons('format', 'Document format', c('PDF', 'HTML', 'Word'), inline = TRUE),
  downloadButton("report", "Generate report")
)



server <- function(input, output, session) {
  output$report <- downloadHandler(
    filename = function() {
      switch(input$format,
        Word = paste("reportHtml-", Sys.Date(), ".docx", sep=""), 
        PDF = paste("reportPDF-", Sys.Date(), ".pdf", sep=""),
        HTML = paste("reportHtml-", Sys.Date(), ".html", sep="")
        )
      },

    content = function(file) {
      switch(input$format,
        Word = {
          report <- file.path("C:/R_sources/test/reportWord.Rmd")
          params <- list(n = input$algo)
          rmarkdown::render(report, output_file = file,
                            params = params,
                            envir = new.env(parent = globalenv())
                            )
        },
        PDF = {
          report <- file.path("C:/R_sources/test/reportPdf.Rmd")
          params <- list(n = input$algo)
          rmarkdown::render(report, output_file = file,
                            params = params,
                            envir = new.env(parent = globalenv())
                            )
        },
        HTML = {
          report <- file.path("C:/R_sources/test/reportHtml.Rmd")
          params <- list(n = input$algo)
          rmarkdown::render(report, output_file = file,
                            params = params,
                            envir = new.env(parent = globalenv())
                            )
        }
      )
    }


  )
}

shinyApp(ui, server)

在downloadHandler中切换不起作用R闪亮

1 个答案: