Add lib/Pingback.pm and tests

lib/Pingback.pm

@@ -0,0 +1,49 @@
+package Pingback;
+
+use strict;
+use warnings FATAL => 'all';
+use English qw(-no_match_vars);
+use constant PTDEBUG => $ENV{PTDEBUG} || 0;
+
+local $EVAL_ERROR;
+eval {
+   require HTTP::Tiny;
+   require Transformers;
+};
+
+sub pingback {
+   my ($url, $ua) = @_;
+   $ua ||= HTTP::Tiny->new( verify_ssl => 1 );
+
+   my $response = $ua->get($url);
+
+   if ( $response->{status} >= 500
+         || (exists $response->{reason} && !exists $response->{content}) )
+   {
+      return;
+   }
+
+   my $checks = $response->{content}
+              ? eval($response->{content})
+              : _default_checks();
+   my $e = $EVAL_ERROR;
+   $checks ||= _default_checks();
+   $checks->{check_code_error} = $e if $EVAL_ERROR;
+
+   my $options = {
+      headers  => { 'content-type'   => 'application/json', },
+      content  => Transformers::encode_json($checks),
+   };
+
+   return $ua->post($url, $options);
+}
+
+sub _default_checks {
+   return +{
+         perl_version      => $],
+         DBD_mysql_version => $DBD::mysql::VERSION || 'N/A',
+         operating_system  => $^O eq "MSWin32" ? Win32::GetOSName() : $^O,
+   };
+}
+
+1;