ensure_files_available {pkgfilecache}

Ensure all given files exist in the file cache, download them if they are not.

Description

Ensure all given files exist in the file cache, download them if they are not.

Usage

ensure_files_available(
  pkg_info,
  relative_filenames,
  urls,
  files_are_binary = NULL,
  md5sums = NULL,
  on_errors = "warn",
  download = TRUE
)

Arguments

pkg_info

named list. Package identifier, see get_pkg_info() on how to get one.

relative_filenames

vector of strings. A vector of filenames, realtive to the package cache.

urls

vector of strings. For each file, a remote URL where to download the file. Will be passed to 'downloader::download', see that function for URL encoding details.

files_are_binary

logical vector. For each file, whether it is binary. Only required on Windows, when files need to be downloaded. See 'downloader::download' docs for details.

md5sums

vector of strings or NULL. A list of MD5 checksums, one for each file in param 'relative_filenames', if not NULL. If given, the files will only be reported as existing if the MD5 sums match.

on_errors

string. What to do if getting the files failed. One of c("warn", "stop", "ignore"). At the end, files are checked using 'files_available'(including MD5 if given). Depending on the check results, the behaviours triggered are: "warn": Print a warning for each file that failed the check. "stop": Stop the script, i.e., the whole application. "ignore": Do nothing. You can still react using the return value.

download

logical. Whether to try downloading missing files. Defaults to TRUE. Existing files (with correct MD5 if available) will never be downloaded.

Value

Named list. The list has entries: "available": vector of strings. The names of the files that are available in the local file cache. You can access them using get_filepath(). "missing": vector of strings. The names of the files that this function was unable to retrieve. "file_status": Logical array indicating whether the files are available. Order is identical to the one in argument 'relative_filenames'.

Examples

   pkg_info = get_pkg_info("mypackage");
   local_relative_filenames = c("local_file1.txt", "local_file2.txt");
   bu = "https://raw.githubusercontent.com/dfsp-spirit/";
   url1 = paste(bu, "pkgfilecache/master/inst/extdata/file1.txt", sep="");
   url2 = paste(bu, "pkgfilecache/master/inst/extdata/file2.txt", sep="");
   urls = c(url1, url2);
   md5sums = c("35261471bcd198583c3805ee2a543b1f", "85ffec2e6efb476f1ee1e3e7fddd86de");
   res = ensure_files_available(pkg_info, local_relative_filenames, urls, md5sums=md5sums);
   erase_file_cache(pkg_info); # clear full cache