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.
appshot(
app,
file = "webshot.png",
...,
port = getOption("shiny.port"),
envvars = NULL
)
# S3 method for character
appshot(
app,
file = "webshot.png",
...,
port = getOption("shiny.port"),
envvars = NULL
)
# S3 method for shiny.appobj
appshot(
app,
file = "webshot.png",
...,
port = getOption("shiny.port"),
envvars = NULL,
webshot_timeout = 60
)A Shiny app object, or a string naming an app directory.
A vector of names of output files. Should end with an image file
type (.png, .jpg, .jpeg, or .webp) or
.pdf. 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. For PDF output, it is just like printing the page to PDF
in a browser; selector, cliprect, expand, and
zoom will not be used for PDFs.
Other arguments to pass on to webshot.
Port that Shiny will listen on.
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.
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.
Invisibly returns the normalized path to all screenshots taken. The character vector will have a class of `"webshot"`.
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")
}