Downloads the images that comprise an issuu publication, uses ImageMagick to convert the jpegs to a PDF. Somewhat glitchy, and not the most stable since it relies on item positions in at least two places (but could probably be rewritten to avoid that).

issuu_downloader.R

library(rvest)
library(jsonlite)
issuu <- function(url) {
  doc <- read_html(url)
  props <- doc %>%
    html_nodes("script") %>%
    .[[4]] %>%
    html_text() %>%
    gsub("window.issuuDataCache = ", "", .) %>%
    fromJSON() %>%
    .[["apiCache"]] %>%
    .[[2]] %>%
    .[["document"]]
  fl <- sprintf("http://image.issuu.com/%s/jpg/page_%d.jpg", props[["documentId"]], seq_len(props[["pageCount"]]))
  cwd <- getwd()
  x <- tempdir()
  print(x)
  setwd(x)
  writeLines(fl, con = "filelist.txt")
  system(sprintf("wget -i filelist.txt", x), show.output.on.console = FALSE, ignore.stdout = TRUE, ignore.stderr = TRUE)
  output <- paste0(gsub("\\s+", "_", props[["title"]]), ".pdf")
  system(sprintf("convert %s %s", paste(basename(fl), collapse = " "), output))
  file.remove(basename(fl))
  file.remove("filelist.txt")
  file.copy(output, "~/")
  file.remove(output)
  setwd(cwd)
  getwd()
  props
}

## Example run....
issuu("http://issuu.com/amnestypublishing/docs/escr_primer")