webshot: appshot – R documentation

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appshot

Take a screenshot of a Shiny app

Description

appshot performs a webshot using two different methods depending upon the object provided. If a 'character' is provided (pointing to an app.R file or app directory) an isolated background R process is launched to run the Shiny application. The current R process then captures the webshot. When a Shiny application object is supplied to appshot, it is reversed: the Shiny application runs in the current R process and an isolated background R process is launched to capture a webshot. The reason it is reversed in the second case has to do with scoping: although it would be preferable to run the Shiny application in a background process and call webshot from the current process, with Shiny application objects, there are potential scoping errors when run this way.

Usage

appshot(app, file = "webshot.png", ..., port = getOption("shiny.port"),
  envvars = NULL)

## S3 method for class 'character'
appshot(app, file = "webshot.png", ...,
  port = getOption("shiny.port"), envvars = NULL)

## S3 method for class 'shiny.appobj'
appshot(app, file = "webshot.png", ...,
  port = getOption("shiny.port"), envvars = NULL,
  webshot_timeout = 60)

Arguments

`app`	A Shiny app object, or a string naming an app directory.
`file`	A vector of names of output files. Should end with `.png`, `.pdf`, or `.jpeg`. If several screenshots have to be taken and only one filename is provided, then the function appends the index number of the screenshot to the file name.
`...`	Other arguments to pass on to `webshot`.
`port`	Port that Shiny will listen on.
`envvars`	A named character vector or named list of environment variables and values to set for the Shiny app's R process. These will be unset after the process exits. This can be used to pass configuration information to a Shiny app.
`webshot_timeout`	The maximum number of seconds the phantom application is allowed to run before killing the process. If a delay argument is supplied (in `...`), the delay value is added to the timeout value.

Examples

if (interactive()) {
  appdir <- system.file("examples", "01_hello", package="shiny")

  # With a Shiny directory
  appshot(appdir, "01_hello.png")

  # With a Shiny App object
  shinyapp <- shiny::shinyAppDir(appdir)
  appshot(shinyapp, "01_hello_app.png")
}

webshot

Take Screenshots of Web Pages

v0.5.2

GPL-2

Authors

Winston Chang [aut, cre], Yihui Xie [ctb], Francois Guillem [ctb], Barret Schloerke [ctb], Nicolas Perriault [ctb] (The CasperJS library)

Initial release