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)