execute_safely: Execute an expression safely in server

In shinyWidgets: Custom Inputs Widgets for Shiny

Execute an expression safely in server

Description

Execute an expression without generating an error, instead display the error to the user in an alert.

Usage

execute_safely(
  expr,
  title = "Error",
  message = "An error occured, detail below:",
  include_error = TRUE,
  error_return = NULL,
  session = shiny::getDefaultReactiveDomain()
)

Arguments

expr	Expression to evaluate
title	Title to display in the alert in case of error.
message	Message to display below title.
include_error	Include the error message generated by R.
error_return	Value to return in case of error.
session	Shiny session.

Value

Result of expr if no error, otherwise the value of error_return (NULL by default to use req in other reactive context).

Examples

library(shiny)
library(shinyWidgets)

ui <- fluidPage(
  tags$h2("Execute code safely in server"),
  fileInput(
    inputId = "file",
    label = "Try to import something else than a text file (Excel for example)"
  ),
  verbatimTextOutput(outputId = "file_value")
)

server <- function(input, output, session) {

  options(warn = 2) # turns warnings into errors
  onStop(function() {
    options(warn = 0)
  })

  r <- reactive({
    req(input$file)
    execute_safely(
      read.csv(input$file$datapath)
    )
  })

  output$file_value <- renderPrint({
    head(r())
  })

}

if (interactive())
  shinyApp(ui, server)

shinyWidgets documentation built on Sept. 23, 2024, 9:07 a.m.