R/helpers.R

In RCzechia: Spatial Objects of the Czech Republic

#' Set the local cache directory
#'
#' The function sets the environment variable RCZECHIA_HOME to be used as a local cache for RCzechia remote files; if unset tempdir() is used instead, with persistence for current session only.
#'
#' Note that when set (it is unset by default) the remote files will be cached to local file system and persist between R sessions, for good or bad.
#'
#' Also note that you can set the value of RCZECHIA_HOME environment variable directly, either via a \code{Sys.setenv()} call or via your \code{.Renviron} file.
#'
#' @param path file to be downloaded (or not...) from S3
#'
#' @return TRUE for success and FALSE for failure; returned silently

set_home <- function(path) {

  if(file.access(path, mode = 2) == 0) {
    Sys.setenv("RCZECHIA_HOME" = path)
    invisible(TRUE)
  } else {
    warning("'path' not found or not writeable; default will be used instead")
    invisible(FALSE)
  }

}

#' Unset the local cache directory
#'
#' The function unsets the environment variable RCZECHIA_HOME, meaning tempdir() will be used in future function calls, and no persistent data will be stored locally.
#'
#' @return TRUE for success and FALSE for failure; returned silently

unset_home <- function() {

  Sys.unsetenv("RCZECHIA_HOME")
  invisible(TRUE)

}