use withr::with_options to pass shiny.maxRequestSize to a shiny app

[VincentGuyader]

use withr::with_options to pass shiny.maxRequestSize to a shiny app

[jimhester]

Does setting the option by hand work, I am guessing no? e.g.

options(shiny.maxRequestSize="find_me")
shiny::shinyApp(ui, server)

[VincentGuyader]

yes, it works :

library(shiny)

ui <- fluidPage(
  verbatimTextOutput("option"),
  verbatimTextOutput("option2"),
  actionButton("go","go")
)

server <- function(input, output, session) {
  output$option <- renderText({getOption("repos")})
  output$option2 <- renderText({ getOption("shiny.maxRequestSize") })
}
options(shiny.maxRequestSize="find_me")
shiny::shinyApp(ui, server)

[jimhester]

There isn't really anything we can do in this package, when you call shiny::shinyApp() R runs the on.exit() handlers for the current block (which is what unsets the option). Here is an example without withr.

# ... code as above
local({
  options(shiny.maxRequestSize = "find_me")
  on.exit({str("hi"); options(shiny.maxRequestSize = NULL)})
  shiny::shinyApp(ui, server)
  })
#> chr "hi"