shiny.semantic (version 0.5.1)

with_progress: Reporting progress (functional API)

Description

Reports progress to the user during long-running operations.

Usage

with_progress(
  expr,
  min = 0,
  max = 1,
  value = min + (max - min) * 0.1,
  message = NULL,
  session = getDefaultReactiveDomain(),
  env = parent.frame(),
  quoted = FALSE
)
withProgress(
  expr,
  min = 0,
  max = 1,
  value = min + (max - min) * 0.1,
  message = NULL,
  session = getDefaultReactiveDomain(),
  env = parent.frame(),
  quoted = FALSE,
  ...
)
setProgress(
  value = NULL,
  message = NULL,
  session = getDefaultReactiveDomain(),
  ...
)
set_progress(
  value = NULL,
  message = NULL,
  session = getDefaultReactiveDomain()
)
incProgress(
  amount = 0.1,
  message = NULL,
  session = getDefaultReactiveDomain(),
  ...
)
inc_progress(
  amount = 0.1,
  message = NULL,
  session = getDefaultReactiveDomain(),
  ...
)

Arguments

expr

The work to be done. This expression should contain calls to `set_progress`.

min

The value that represents the starting point of the progress bar. Must be less tham `max`. Default is 0.

max

The value that represents the end of the progress bar. Must be greater than `min`. Default is 1.

value

Single-element numeric vector; the value at which to set the progress bar, relative to `min` and `max`.

message

A single-element character vector; the message to be displayed to the user, or `NULL` to hide the current message (if any).

session

The Shiny session object, as provided by `shinyServer` to the server function. The default is to automatically find the session by using the current reactive domain.

env

The environment in which `expr` should be evaluated.

quoted

Whether `expr` is a quoted expression (this is not common).

...

Arguments that may have been used in `shiny::withProgress`

amount

For `inc_progress`, the amount to increment the status bar. Default is 0.1.

Details

This package exposes two distinct programming APIs for working with progress. Using `with_progress` with `inc_progress` or `set_progress` provide a simple function-based interface, while the [Progress()] reference class provides an object-oriented API.

Use `with_progress` to wrap the scope of your work; doing so will cause a new progress panel to be created, and it will be displayed the first time `inc_progress` or `set_progress` are called. When `with_progress` exits, the corresponding progress panel will be removed.

The `inc_progress` function increments the status bar by a specified amount, whereas the `set_progress` function sets it to a specific value, and can also set the text displayed.

Generally, `with_progress`/`inc_progress`/`set_progress` should be sufficient; the exception is if the work to be done is asynchronous (this is not common) or otherwise cannot be encapsulated by a single scope. In that case, you can use the `Progress` reference class.

When migrating from shiny applications, the functions `withProgress`, `incProgress` and `setProgress` are aliases for `with_progress`, `inc_progress` and `set_progress`.

See Also

[Progress()]

Examples

## Only run examples in interactive R sessions
if (interactive()) {

ui <- semanticPage(
  plotOutput("plot")
)

server <- function(input, output) {
  output$plot <- renderPlot({
    with_progress(message = 'Calculation in progress',
                 detail = 'This may take a while...', value = 0, {
      for (i in 1:15) {
        inc_progress(1/15)
        Sys.sleep(0.25)
      }
    })
    plot(cars)
  })
}

shinyApp(ui, server)
}