Add a ZMQ perl exmple

examples/Perl5/client.pl

@@ -0,0 +1,38 @@
+#!/usr/bin/env perl
+
+use JSON::XS 'decode_json';
+use ZMQ::FFI qw(ZMQ_SUB);
+use Time::HiRes q(usleep);
+use Compress::Zlib;
+
+sub msg {
+  printf STDERR @_;
+}
+
+my $endpoint = "tcp://eddn.edcd.io:9500";
+my $ctx      = ZMQ::FFI->new();
+
+my $s = $ctx->socket(ZMQ_SUB);
+
+$s->connect($endpoint);
+
+$s->subscribe('');
+while(1)
+{
+  usleep 100_000 until ($s->has_pollin);
+  my $data = $s->recv();
+
+  # turn the json into a perl hash
+  my $pj = decode_json(uncompress($data));
+  my $schema = $pj->{'$schemaRef'};
+  msg "schema = %s\n", $schema;
+  msg "  software = %s\n", $pj->{header}->{softwareName};
+  if ($schema eq "https://eddn.edcd.io/schemas/journal/1") {
+    my $event = $pj->{message}->{event};
+    if ($event eq "FSDJump") {
+      msg "  StarSystem = %s\n", $pj->{message}->{StarSystem};
+    }
+  }
+  msg "------\n";
+}
+$s->unsubscribe('');