闪亮服务器，openxlsx图表无法插入

Question

闪亮服务器，openxlsx图表无法插入

rshinyshiny-server

3

当使用runApp()从控制台运行以下闪亮的应用程序时，它按预期工作，显示绘图并提供下载包含绘图的Excel文件的功能。在shiny-server上运行相同的应用程序会产生以下错误：

无法打开文件'Rplots.pdf'

Shiny Server v1.4.2.786
Node.js v0.10.40
R version 3.3.1 (2016-06-21) -- "Bug in Your Hair"

Ubuntu 14.04.4 LTS

library(shiny)
library(openxlsx)
library(magrittr)

# Define UI for application that draws a histogram
ui <- shinyUI(fluidPage(

   # Application title
   titlePanel("Old Faithful Geyser Data"),

   # Sidebar with a slider input for number of bins 
   sidebarLayout(
      sidebarPanel(
         sliderInput("bins",
                     "Number of bins:",
                     min = 1,
                     max = 50,
                     value = 30),
         downloadButton('specDataDownload',
                        label = "Download",
                        class = NULL)
      ),

      # Show a plot of the generated distribution
      mainPanel(
         plotOutput("distPlot")
      )
   )
))

# Define server logic required to draw a histogram
server <- shinyServer(function(input, output) {

   output$distPlot <- renderPlot({
      # generate bins based on input$bins from ui.R
      x    <- isolate({faithful[, 2] })
      bins <- seq(min(x), max(x), length.out = input$bins + 1)

      # draw the histogram with the specified number of bins
      hist(x, breaks = bins, col = 'darkgray', border = 'white')

   })
   output$specDataDownload <- downloadHandler(
       filename = function() {
           paste("ProcessedPlateAssay",
                 gsub("-|[[:space:]]|:",
                      "",
                      Sys.time()),
                 ".xlsx",
                 sep = "_")
       },
       content = function(con) {
           x    <- isolate({faithful[, 2] })
           bins <- seq(min(x), max(x), length.out = input$bins + 1)
           output <- createWorkbook()
           addWorksheet(
               output,
               "One")
           hist(
               x,
               breaks = bins,
               col = 'darkgray',
               border = 'white')
           insertPlot(
               output,
               sheet = 1,
               startRow = (1),
               startCol = 5,
               width = 6.5,
               height = 3,
               fileType = "png",
               units = "in",
               dpi = 600)

       saveWorkbook(
           wb = output,
           file = con
       )
       })
})

# Run the application 
shinyApp(ui = ui, server = server)

- bwbioinfo

遇到了相同的问题。以下是我们解决的方法：(1) 使用jpeg打开一个（临时）图像；(2) 执行您的绘图命令，(3) 关闭jpeg，使用insertImage。 - undefined

嗨，我最终也解决了那个问题，但根本的问题是我的服务器上的Shiny用户没有对文件夹有写入权限（它是作为一个Git仓库创建并推送到服务器的）。 - undefined

1个回答

网页内容由stack overflow 提供, 点击上面的

可以查看英文原文，
原文链接

- Joseph Kigotho · Accepted Answer

我想提供一个最简单的例子，因为我一直在努力解决openxlsx的insertPlot函数在shiny-server内无法正常工作的问题，可能是由于tempfile或dev.copy权限问题所致。对我来说最有效的方法是使用ggsave，因为它非常好地处理了分辨率，并且还有一个比例参数，可以调整图像元素的大小，使其更适合演示。我还包括了使用png函数的第二种方法。

下面是一个可重现的例子，部分取自@sebkopf在Save plots made in a shiny app中的答案。

library(shiny)
library(openxlsx)
library(ggplot2)

ui <- fluidPage(
  downloadLink("downloadExcel", "Excel Graph Download")
)

server <- function(input, output) {

  p1 <- qplot(mpg, data=mtcars, geom="density", fill=as.factor(gear), 
alpha=I(.5), main="Distribution of Gas Mileage")
  p2 <- qplot(age, circumference, data = Orange, geom = c("point", "line"), 
colour = Tree)

  output$downloadExcel <- downloadHandler(
    filename = "savePlot.xlsx",
    content = function(file){
      wb <- createWorkbook()

      addWorksheet(wb, "ggsave", gridLines = F)
      addWorksheet(wb, "png", gridLines = F)

      # Method 1: using ggsave

      ggsave("p1.png", plot = p1, scale = .6) # Scale parameter resizes the object making text more legible
      ggsave("p2.png", plot = p2, scale = .6)

      insertImage(wb, "ggsave", "p1.png", width = 5, height = 3.5)
      insertImage(wb, "ggsave", "p22.png", startCol = "J", width = 16, height = 10, units = "cm")

      # Method 2: using png function

      png("p11.png")
      print(p1)
      dev.off()

      insertImage(wb, "png", "p11.png", width = 5, height = 3.5)

      png("p22.png")
      print(p2)
      dev.off()

      insertImage(wb, "png", "p22.png", startCol = "J", width = 16, height = 10, units = "cm")

      saveWorkbook(wb, file, overwrite = T)

      unlink(c("p1", "p2", "p11", "p22")) # To remove the images from the server
    }
  )
}

shinyApp(ui, server)