Making odbr fail gracefully (Closes #12)

R/download_piggyback.R

@@ -0,0 +1,45 @@
+#' Download file from odbr using piggyback
+#'
+#' @param filename_to_download String. The name of the file to be downloaded.
+#' @param force_download Logical. If `FALSE` (default) the function will read
+#' cached data downloaded previously in the same session. If `TRUE`, the
+#' function will download the data and overwrite cached data.
+#'
+#' @return A string with the path to the file saved in a tempdir
+#'
+#' @keywords internal
+download_piggyback <- function(filename_to_download,
+ force_download = FALSE) {
+
+ # Defining our temporary directory
+ temp_dest_dir <- tempdir(check = TRUE)
+
+ # Creating the temporary folder effectively
+ fs::dir_create(path = temp_dest_dir, recurse = TRUE)
+
+ # Creating path + filename and saving to "temporary_filename"
+ temp_full_file_path <- paste0(temp_dest_dir, "/", filename_to_download)
+
+ if (!file.exists(temp_full_file_path) || force_download) {
+
+ # downloading the file from a release of the odbr repo - release specified in the parameter
+ try(silent = TRUE,
+ piggyback::pb_download(
+ file = filename_to_download,
+ repo = "hsvab/odbr",
+ dest = temp_dest_dir
+ )
+ )
+ }
+
+ # Halt function if download failed
+ if (!file.exists(temp_full_file_path) ) {
+ message('Internet connection not working properly.')
+ return(invisible(NULL))
+
+ } else {
+ # return string with the path to the file saved in a tempdir
+ return(temp_full_file_path)
+ }
+
+}

R/read_map.R

@@ -82,6 +82,9 @@
  # parameter and saving the function return in "temporary_filename"
  temporary_filename <- download_piggyback(filename_to_download, force_download)
 
+ # check if download worked
+ if(is.null(temporary_filename)) { return(NULL) }
+
  # Reading shape files
  od_map <- sf::read_sf(temporary_filename)
 

R/read_od.R

@@ -51,6 +51,9 @@
  # parameter and saving the return in "temporary_filename"
  temporary_filename <- download_piggyback(filename_to_download, force_download)
 
+ # check if download worked
+ if(is.null(temporary_filename)) { return(NULL) }
+
  # Reading the file to a release in odbr repository
  od_file <- data.table::fread(temporary_filename,
  sep = ";"