如何通过 Shiny 上的 downloadHandler 下载工作簿？答案

【问题标题】：How to download workbook via downloadHandler on Shiny?如何通过 Shiny 上的 downloadHandler 下载工作簿？
【发布时间】：2020-04-30 06:32:50
【问题描述】：

我们如何将工作簿保存在某个文件夹中并提供给用户下载？

参考： Shiny + downloadHandler + Openxlsx does not generate a xlsx file

程序：

创建数据
另存为工作簿
使其可通过以下方式下载将其读取为 xlsx 文件

即使将工作簿写入文件夹，下载该工作簿时出错。

library(shiny)
library(openxlsx)
library(writexl)
library(tidyverse)
ui <- fluidPage(
  downloadButton("dl", "Download")
)

server <- function(input, output) {
  data1 = mtcars[,c(1,2)] %>% head() # data for Col 1 ,until Row 6
  data2 = gapminder::gapminder[,c(1,4)] %>% head() # data for Col 1 , Row from 8 until Row 13
  data3 = mtcars[,c(1,2)] %>% tail() # data for Col 1 , Row from 15 until Row 20

  # Creating a workbook for user to download
  wb <- createWorkbook()
  addWorksheet(wb, sheetName = "sheet1")
  writeData(wb, sheet = 1, x = data1, startCol = 1, startRow = 1)
  writeData(wb, sheet = 1, x = data2, startCol = 1, startRow = 8)
  writeData(wb, sheet = 1, x = data3, startCol = 1, startRow = 15)
  ex_wb <- paste0("example", ".xlsx")
  saveWorkbook(wb, file = ex_wb, overwrite = TRUE)

  output$dl <- downloadHandler(
    filename = function(){ex_wb # filename
      },
    content = function(file) {
      # Content to be available for user to download 
      read.xlsx(ex_wb) # Making dataframe available for user to download
    })
}
shinyApp(ui, server)

【问题讨论】：

我认为在 Rstudio 中使用 downloadHandler 会导致问题。您是否尝试在 chrome 或其他浏览器中运行您的应用以查看它是否可以在那里运行？
感谢您的建议。实际上，当我们运行该应用程序时，它会在 Chrome 本身中弹出。但是点击下载按钮时发生错误

标签： r shiny downloadfile openxlsx

【解决方案1】：

试试这个：

library(shiny)
library(openxlsx)
library(writexl)
library(tidyverse)
ui <- fluidPage(
  downloadButton("dl", "Download")
)

server <- function(input, output) {
  data1 <- mtcars[, c(1, 2)] %>% head() # data for Col 1 ,until Row 6
  data2 <- gapminder::gapminder[, c(1, 4)] %>% head() # data for Col 1 , Row from 8 until Row 13
  data3 <- mtcars[, c(1, 2)] %>% tail() # data for Col 1 , Row from 15 until Row 20

  # Creating a workbook for user to download
  wb <- createWorkbook()
  addWorksheet(wb, sheetName = "sheet1")
  writeData(wb, sheet = 1, x = data1, startCol = 1, startRow = 1)
  writeData(wb, sheet = 1, x = data2, startCol = 1, startRow = 8)
  writeData(wb, sheet = 1, x = data3, startCol = 1, startRow = 15)


  output$dl <- downloadHandler(
    filename = function() {
      paste0("example", ".xlsx")
    },
    content = function(file) {
      saveWorkbook(wb, file = file, overwrite = TRUE)
    }
  )
}
shinyApp(ui, server)

【讨论】：