[EXPERIMENTAL, DO NOT USE]
The goal of {elvis} is to provide safer render* and observe* in
{shiny} by providing a native tryCatch() mechanism.
Note that this is an experimental package, so the API might change and some stuff might be buggy.
You can install the development version of elvis like so:
remotes::install_github("thinkr-open/elvis")You’re reading the doc about version : 0.0.0.9000
This README has been compiled on the
Sys.time()
#> [1] "2023-03-27 11:49:29 CEST"Here are the test & coverage results :
devtools::check(quiet = TRUE)
#> ℹ Loading elvis
#> ── R CMD check results ─────────────────────────────────── elvis 0.0.0.9000 ────
#> Duration: 5.9s
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#> 0 errors ✔ | 0 warnings ✔ | 0 notes ✔covr::package_coverage()
#> elvis Coverage: 0.00%
#> R/observer.R: 0.00%
#> R/renderDataTable.R: 0.00%
#> R/renderImage.R: 0.00%
#> R/renderPlot.R: 0.00%
#> R/renderPrint.R: 0.00%
#> R/renderTable.R: 0.00%
#> R/renderText.R: 0.00%
#> R/renderUI.R: 0.00%
#> R/utils.R: 0.00%By default, {shiny} observers and renderers are not safe, and might
stop your app when they fail. One solution is to wrap your code inside
tryCatch, but that might be cumbersum to do this every time.
Here comes {elvis}, a series of wrappers around {shiny} observers
and renderers that have built in tryCatch.
output$plot <- try_renderPlot({
stop("a")
},
errorHandler = function(e){
showNotification("There was an error in the plot")
}
)The base idea is to prefix all the functions with try_, so that it’s
easier to port old code to {elvis}.
Here is a simple example:
library(shiny)
library(elvis)
ui <- fluidPage(
actionButton("go", "Go"),
plotOutput("plot")
)
server <- function(input, output, session) {
r <- reactiveValues(count = 0)
output$plot <- try_renderPlot(
{
if (input$go %% 2 == 0) {
plot(sample(1:100, 10))
} else {
stop("Nop")
}
},
errorHandler = function(e) {
isolate({
r$count <- r$count + 1
})
}
)
observeEvent(
r$count,
{
cli::cli_alert_danger(
sprintf("It's been %s times", r$count)
)
}
)
}
shinyApp(ui, server)library(elvis)
library(shiny)
ui <- fluidPage(
sliderInput("try_observeEvent", "try_observeEvent", 1, 100, 10),
sliderInput("try_observe", "try_observe", 1, 100, 10)
)
server <- function(input, output, session) {
try_observeEvent(
input$try_observeEvent,
ignoreInit = TRUE,
{
stop("pif")
},
errorHandler = function(e) {
showModal(
modalDialog(
easyClose = TRUE,
title = "There was an error in the try_observeEvent"
)
)
}
)
# This one is here to prove that it works with non failing code
try_observeEvent(
input$try_observeEvent,
ignoreInit = TRUE,
{
print(input$try_observeEvent)
}
)
try_observe(
{
input$try_observe
stop("paf")
},
errorHandler = function(e) {
showModal(
modalDialog(
easyClose = TRUE,
title = "There was an error in the try_observe"
)
)
}
)
# This one is here to prove that it works with non failing code
try_observe({
print(input$try_observe)
})
}
shinyApp(ui, server)- try_renderPlot
library(elvis)
library(shiny)
ui <- fluidPage(
actionButton("plot", "Try to renderPlot"),
plotOutput("plot"),
plotOutput("plot2")
)
server <- function(input, output, session) {
output$plot <- try_renderPlot(
{
input$plot
stop("a")
},
errorHandler = function(e) {
showNotification(
"There was an error in the plot",
type = "error"
)
}
)
# This one is here to prove that it works with non failing code
output$plot2 <- try_renderPlot({
input$plot
plot(sample(1:100, 10))
})
}
shinyApp(ui, server)- try_renderDataTable
library(elvis)
library(shiny)
ui <- fluidPage(
actionButton("dt", "Try to renderDataTable"),
dataTableOutput("dt"),
dataTableOutput("dt2")
)
server <- function(input, output, session) {
output$dt <- try_renderDataTable(
{
input$dt
stop("a")
},
errorHandler = function(e) {
showNotification(
"There was an error in the DT",
type = "error"
)
}
)
# This one is here to prove that it works with non failing code
output$dt2 <- try_renderDataTable({
input$dt
mtcars[
sample(1:nrow(mtcars), 10),
]
})
}
shinyApp(ui, server)- try_renderImage
library(elvis)
library(shiny)
library(zeallot)
c(img1, img2, img3) %<-% replicate(
3,
(\(x){
tempfile(fileext = ".jpg")
})()
)
download.file(
"https://www.widermag.com/media/krup1.jpg",
img1
)
download.file(
"https://www.cafeducycliste.com/fr_fr/wp/wp-content/uploads/2022/02/Anton-topbanner-10-02-22.jpg",
img2
)
download.file(
"https://www.suunto.com/globalassets/suunto-blogs/2021/03-march/anton-krupicka/2021-03-anton-blog-intro-body-1.jpg",
img3
)
# Three images
ui <- fluidPage(
actionButton("img", "Try to renderImage"),
imageOutput("img"),
imageOutput("img2")
)
server <- function(input, output, session) {
output$img <- try_renderImage(
{
input$img
stop("a")
},
errorHandler = function(e) {
showNotification(
"There was an error in the img",
type = "error"
)
}
)
# This one is here to prove that it works with non failing code
output$img2 <- try_renderImage({
input$img
outfile <- sample(
c(
img1,
img2,
img3
),
1
)
list(
src = outfile,
alt = "This is alternate text"
)
})
}
shinyApp(ui, server)- try_renderPrint
library(elvis)
library(shiny)
ui <- fluidPage(
actionButton("rp", "Try to try_renderPrint"),
verbatimTextOutput("rp"),
verbatimTextOutput("rp2")
)
server <- function(input, output, session) {
output$rp <- try_renderPrint(
{
input$rp
stop("a")
},
errorHandler = function(e) {
showNotification(
"There was an error in the print",
type = "error"
)
}
)
# This one is here to prove that it works with non failing code
output$rp2 <- try_renderPrint({
input$rp
sample(1:100, 10)
})
}
shinyApp(ui, server)- try_renderText
library(elvis)
library(shiny)
ui <- fluidPage(
actionButton("rt", "Try to try_renderText"),
textOutput("rt"),
textOutput("rt2")
)
server <- function(input, output, session) {
output$rt <- try_renderText(
{
input$rt
stop("a")
},
errorHandler = function(e) {
showNotification(
"There was an error in the text",
type = "error"
)
}
)
# This one is here to prove that it works with non failing code
output$rt2 <- try_renderText({
input$rt
sample(letters, 10)
})
}
shinyApp(ui, server)- try_renderTable
library(elvis)
library(shiny)
ui <- fluidPage(
actionButton("dt", "Try to try_renderTable"),
tableOutput("dt"),
tableOutput("dt2")
)
server <- function(input, output, session) {
output$dt <- try_renderTable(
{
input$dt
stop("a")
},
errorHandler = function(e) {
showNotification(
"There was an error in the table",
type = "error"
)
}
)
# This one is here to prove that it works with non failing code
output$dt2 <- try_renderTable({
input$dt
mtcars[
sample(1:nrow(mtcars), 10),
]
})
}
shinyApp(ui, server)- try_renderUI
library(elvis)
library(shiny)
ui <- fluidPage(
actionButton("ui", "Try to try_renderUI"),
uiOutput("ui"),
uiOutput("ui2")
)
server <- function(input, output, session) {
output$ui <- try_renderUI(
{
input$ui
stop("a")
},
errorHandler = function(e) {
showNotification(
"There was an error in the UI",
type = "error"
)
}
)
# This one is here to prove that it works with non failing code
output$ui2 <- try_renderUI({
input$ui
sample(letters, 1)
})
}
shinyApp(ui, server)With {elvis}, you’re t(rying to r)ender, t(ry)render, tender… and love
me tender, love me true.
Please note that the elvis project is released with a Contributor Code of Conduct. By contributing to this project, you agree to abide by its terms.