slServer {shinylight}

Start a ShinyLight server

Description

Start a ShinyLight server

Usage

slServer(
  interface,
  appDir = NULL,
  host = "127.0.0.1",
  port = NULL,
  daemonize = FALSE,
  initialize = NULL
)

Arguments

interface

List of functions you want to be able to call from the browser. If you want to use the Shinylight Framework, this should have one member getSchema. For details of this, see the documentation for [shinylightFrameworkStart].

appDir

Directory containing files to serve (for example system.file("www", package = "your-package"))

host

IP address to listen on, default is "127.0.0.1" (localhost). Use "0.0.0.0" to run in a docker container.

port

Internet port of the virtual server. If not defined, a random free port will be chosen and the browser will be opened to show the GUI.

daemonize

If TRUE, keep serving forever without returning. This is useful when called from RScript, to keep

initialize

A json string or list (that will be converted to a JSON string) to be passed to the JavaScript as initial data. For non-framework apps, the index.html must contain a line containing var shinylight_initial_data=, which will be replaced with code that sets shinylight_initial_data to this supplied JSON string.

Value

server object, unless daemonize is TRUE in which case the function will not return.

See Also

slStop to stop a running server, and slRunRServer to run a server that just accepts R code.

Examples

# You can leave out port and daemonize to launch a browser
# pointing at your server
server <- slServer(
  port = 50052,
  interface = list(
    multiply = function(x, y) { x * y }
  )
)
# Normally we would use shinylight.js to send the function over
# and receive the result, not R and websocket.
ws <- websocket::WebSocket$new("ws://127.0.0.1:50052/x")
resultdata <- NULL
ws$onMessage(function(event) {
  resultdata <<- jsonlite::fromJSON(event$data)$result$data
})
ws$onOpen(function(event) {
  ws$send('{ "method": "multiply", "params": { "x": 3, "y": 47 } }')
})
timeout = 30
while(is.null(resultdata) && 0 < timeout) {
  later::run_now()
  Sys.sleep(0.1)
  timeout <- timeout - 1
}
ws$close()
slStop(server)
stopifnot(resultdata == 141)  # multiply(3, 47) == 141
grDevices::png()  # workaround; you do not have to do this