+
+# opts is a hash ref with the following known properties
+# hash_required - if 1, at least one checksum has to be specified otherwise an error will be thrown
+# http_proxy
+# https_proxy
+# verify_certificates - if 0 (false) we tell wget to ignore untrusted TLS certs. Default to true
+# md5sum|sha(1|224|256|384|512)sum - the respective expected checksum string
+sub download_file_from_url {
+ my ($dest, $url, $opts) = @_;
+
+ my ($checksum_algorithm, $checksum_expected);
+ for ('sha512', 'sha384', 'sha256', 'sha224', 'sha1', 'md5') {
+ if (defined($opts->{"${_}sum"})) {
+ $checksum_algorithm = $_;
+ $checksum_expected = $opts->{"${_}sum"};
+ last;
+ }
+ }
+ die "checksum required but not specified\n" if ($opts->{hash_required} && !$checksum_algorithm);
+
+ print "downloading $url to $dest\n";
+
+ my $tmpdest = "$dest.tmp.$$";
+ eval {
+ if (-f $dest && $checksum_algorithm) {
+ print "calculating checksum of existing file...";
+ my $checksum_got = get_file_hash($checksum_algorithm, $dest);
+
+ if (lc($checksum_got) eq lc($checksum_expected)) {
+ print "OK, got correct file already, no need to download\n";
+ return;
+ } else {
+ # we could re-download, but may not be safe so just abort for now..
+ die "mismatch (got '$checksum_got' != expect '$checksum_expected'), aborting\n";
+ }
+ }
+
+ local $SIG{INT} = sub {
+ unlink $tmpdest or warn "could not cleanup temporary file: $!";
+ die "got interrupted by signal\n";
+ };
+
+ { # limit the scope of the ENV change
+ local %ENV;
+ if ($opts->{http_proxy}) {
+ $ENV{http_proxy} = $opts->{http_proxy};
+ }
+ if ($opts->{https_proxy}) {
+ $ENV{https_proxy} = $opts->{https_proxy};
+ }
+
+ my $cmd = ['wget', '--progress=dot:giga', '-O', $tmpdest, $url];
+
+ if (!($opts->{verify_certificates} // 1)) { # default to true
+ push @$cmd, '--no-check-certificate';
+ }
+
+ run_command($cmd, errmsg => "download failed");
+ }
+
+ if ($checksum_algorithm) {
+ print "calculating checksum...";
+
+ my $checksum_got = get_file_hash($checksum_algorithm, $tmpdest);
+
+ if (lc($checksum_got) eq lc($checksum_expected)) {
+ print "OK, checksum verified\n";
+ } else {
+ die "ERRROR, checksum mismatch: got '$checksum_got' != expect '$checksum_expected'\n";
+ }
+ }
+
+ rename($tmpdest, $dest) or die "unable to rename temporary file: $!\n";
+ };
+ if (my $err = $@) {
+ unlink $tmpdest or warn "could not cleanup temporary file: $!";
+ die $err;
+ }
+
+ print "download of '$url' to '$dest' finished\n";
+}
+
+sub get_file_hash {
+ my ($algorithm, $filename) = @_;
+
+ my $algorithm_map = {
+ 'md5' => sub { Digest::MD5->new },
+ 'sha1' => sub { Digest::SHA->new(1) },
+ 'sha224' => sub { Digest::SHA->new(224) },
+ 'sha256' => sub { Digest::SHA->new(256) },
+ 'sha384' => sub { Digest::SHA->new(384) },
+ 'sha512' => sub { Digest::SHA->new(512) },
+ };
+
+ my $digester = $algorithm_map->{$algorithm}->() or die "unknown algorithm '$algorithm'\n";
+
+ open(my $fh, '<', $filename) or die "unable to open '$filename': $!\n";
+ binmode($fh);
+
+ my $digest = $digester->addfile($fh)->hexdigest;
+
+ return lc($digest);
+}
+