Progress bars

[hadley]

Possible in principle, but currently make it very easy to crash R.

library(httr)
down_progress <- function() {
  bar <- NULL

  function(down, up) {
    total <- down[1]
    if (total == 0) {
      cat(".")
      return()
    }

    current <- down[2]
    if (is.null(bar)) {
      bar <<- txtProgressBar(max = total)
    }
    setTxtProgressBar(bar, current)
  }
}
prg <- config(noprogress = 0L, progressfunction = down_progress())
x <- GET("http://courses.had.co.nz/12-oscon/slides.zip", prg)
x <- GET("https://dl.dropbox.com/u/41902/ggplot2-course.zip", prg)

[leeper]

There have been two discussions on StackOverflow recently that might be relevant to this:

• http://stackoverflow.com/questions/21969948/undocumented-rcurl-progressfunction-with-url-redirection
• http://stackoverflow.com/questions/21731548/rcurl-display-progress-meter-in-rgui

[hadley]

Can't do safely (i.e. without risking of crashing R) until omegahat/RCurl#10 is fixed.