R - Pack multiple files in a zip

zipack.R

#' Pack multiple files in a zip
#'
#' @export
#' @param fz Complete zip filename and path
#' @param fs Named List. Names are files names and content to be passed to FUN
#' @param FUN Function for writing to disc (defautl write.csv). Has to accept content as
#' first argument and file name as second. Other arguments are passed using ...
#' @param temp.dir Temporary directory to write files and zip. Is appened to file names
#' if not NULL.
#' @param flags A character string of flags to be passed to the command. Defaults is \code{-r9Xj}
#' See more at \link{zip{utils}} and \url{http://www.info-zip.org/mans/zip.html}.
#' @param ... other arguments passded to FUN
#' @details If you receive a status 127 it might be due to the path to zip.exe being undefined
#' you can set it using Sys.setenv(R_ZIPCMD="/usr/bin/zip") or
#' Sys.setenv(R_ZIPCMD="c:/rtools/bin/zip.exe") on windows. You can also set it permanently
#' system-wide by adding the directory to the path.
zipack <- function(fz, fs, FUN=write.csv, temp.dir=dirname(fz), flags="-r9Xj", ...) {
  if(!file.exists(temp.dir))  dir.create(temp.dir)
  if(!is.null(temp.dir)) names(fs) <- file.path(temp.dir, names(fs))
  
  # write files to temp dir
  lapply(1:length(fs), function(i) FUN(fs[[i]], file=names(fs[i]), ...))

  # compress
  res <- zip(zipfile=fz, files=names(fs), flags = flags)
  # cleanup
  lapply(names(fs), unlink)
  # return path
  attr(fz, "contentType") =  "application/zip"
  return(invisible(fz))
}