init

init

mod/addChecksum.pl

@@ -0,0 +1,83 @@
+#!/usr/bin/perl
+
+#############################################################################
+# To add a checksum to a subscription file, run the script like this:       #
+#   perl addChecksum.pl subscription.txt                                    #
+#############################################################################
+
+use strict;
+use warnings;
+use Digest::MD5 qw(md5_base64);
+
+die "Usage: $^X $0 subscription.txt\n" unless @ARGV;
+
+#my $file = $ARGV[0];
+foreach my $file (@ARGV) {
+  my $data = readFile($file);
+
+  # Get existing checksum.
+  $data =~ /^.*!\s*checksum[\s\-:]+([\w\+\/=]+).*\n/gmi;
+  my $oldchecksum = $1;
+
+  # Remove already existing checksum.
+  $data =~ s/^.*!\s*checksum[\s\-:]+([\w\+\/=]+).*\n//gmi;
+
+  # Calculate new checksum: remove all CR symbols and empty
+  # lines and get an MD5 checksum of the result (base64-encoded,
+  # without the trailing = characters).
+  my $checksumData = $data;
+  $checksumData =~ s/\r//g;
+  $checksumData =~ s/\n+/\n/g;
+
+  # Calculate new checksum
+  my $checksum = md5_base64($checksumData);
+
+  # If the old checksum matches the new one bail.
+  if ($checksum eq $oldchecksum)
+  {
+    $data = ();
+    next;
+  }
+
+  # Update the date.
+  my @months = qw(Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec);
+  my ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localtime();
+  $year += 1900; # Year is years since 1900.
+  my $todaysdate = "$mday $months[$mon] $year";
+  $data =~ s/(^.*!.*Updated:\s*)(.*)\s*$/$1$todaysdate/gmi;
+
+  # Recalculate the checksum as we've altered the date.
+  $checksumData = $data;
+  $checksumData =~ s/\r//g;
+  $checksumData =~ s/\n+/\n/g;
+  $checksum = md5_base64($checksumData);
+
+  # Insert checksum into the file
+  $data =~ s/(\r?\n)/$1! Checksum: $checksum$1/;
+
+  writeFile($file, $data);
+  $data = ();
+}
+
+sub readFile
+{
+  my $file = shift;
+
+  open(local *FILE, "<", $file) || die "Could not read file '$file'";
+  binmode(FILE);
+  local $/;
+  my $result = <FILE>;
+  close(FILE);
+
+  return $result;
+}
+
+sub writeFile
+{
+  my ($file, $contents) = @_;
+
+  open(local *FILE, ">", $file) || die "Could not write file '$file'";
+  binmode(FILE);
+  print FILE $contents;
+  close(FILE);
+}