Enable image magick ghostscript features

[samperman]

See https://www.kb.cert.org/vuls/id/332928/
Enable features on focal since ghostscript is new enough

Fixes #286

[dcaud]

Today, I relaunched an old app (with the exact same code as another app that is currently function) and am now getting this same error that caused this issue initially:

"R: attempt to perform an operation not allowed by the security policy `PDF' @ error/constitute.c/IsCoderAuthorized/421"

I wonder if this is related to upgrading Ubuntu to Jammy last month: #356

Either way, this is a drastic problem for multiple of my apps at the moment. Any ideas for a quick fix?

[dcaud]

Below is an example app that reproduces the error. Downloading a jpeg works, but not writing and downloading a PDF. Both work locally on my Mac.

library(shiny)
library(magick)

ui <- fluidPage(
  titlePanel("Error when downloading as PDF"),
  
  sidebarLayout(
    sidebarPanel(
      radioButtons("fileType", "Choose File Type:",
                   choices = c("PDF", "JPEG"),
                   selected = "PDF"),
      downloadButton("downloadFile", "Download")
    ),
    
    mainPanel(
      imageOutput("displayImage")
    )
  )
)

server <- function(input, output, session) {
  
  img <- image_read("wizard:")
  
  output$displayImage <- renderImage({
    tmp <- tempfile(fileext = ".png")
    image_write(img, path = tmp, format = "png")
    list(src = tmp)
  }, deleteFile = TRUE)
  
  output$downloadFile <- downloadHandler(
    filename = function() {
      if (input$fileType == "PDF") {
        paste0("converted_", Sys.Date(), ".pdf")
      } else {
        paste0("converted_", Sys.Date(), ".jpeg")
      }
    },
    content = function(file) {
      if (input$fileType == "PDF") {
        # The write function w/ PDF seems to be at odds with a policy that can be revised.
        image_write(img, path = file, format = "pdf")
      } else {
        image_write(img, path = file, format = "jpeg")
      }
    }
  )
}

shinyApp(ui = ui, server = server)

[dcaud]

I believe this was probably solved before by removing the entire policy.xml: #323

[dcaud]

It looks like the install script and test from the focal version didn't make it into the current jammy version.

This fix might require updating the install script.

Something like switching this code from:

if [ ${OS_CODENAME} == "focal" ]; then

to

if [ "${OS_CODENAME}" == "focal" ] || [ "${OS_CODENAME}" == "jammy" ]; then

But a test to see if the policy.xml file is still in the same referenced path would be great!