Is it possible to stop executing of R code inside shiny (without stopping the shiny process)?

Question

Let\'s say I have a shiny app that has a function that can take a long time to run. Is it possible to have a \"stop\" button that tells R to stop the long-running call, wit

Answer 1

What about httpuv::service() ?

library(shiny)
analyze <- function(session=shiny::getDefaultReactiveDomain()){
  continue = TRUE
  lapply(1:100, function(x) {
    if(continue){
      print(x)
      Sys.sleep(1)
      # reload inputs
      httpuv:::service()
      continue <<- !isTRUE(session$input$stopThis)
    }
  }
  )
}

shinyApp(
  ui = fluidPage(
    actionButton("start","Start",class="btn-primary", onclick="Shiny.onInputChange('stopThis',false)"),
    actionButton("stop","Stop",class="btn-danger", onclick="Shiny.onInputChange('stopThis',true)")
  ),
  server = function(input, output, session) {
    observeEvent(input$start, {
      analyze()
    })
  }
)