Perl issues while sending emojis over socket - json

Question

My Perl script sends push notifications to an Apple APNS server. It works except when I try to send emojis (special characters).
My code
use DBI;
use JSON;
use Net::APNS::Persistent;
use Data::Dumper;
use Encode;
my $cfg;
my $apns;
...;
sub connect {
my ($sandbox, $cert, $key, $pass) = $cfg->getAPNSServer();
$apns = Net::APNS::Persistent->new({
sandbox => $sandbox,
cert => $cert,
key => $key,
}) or die("[-] Unable to connect to APNS server");
}
sub push {
my $msg = $_[1];
Logger::log(5, "[APNS Client] Got message ".Dumper($msg));
#Encode::_utf8_off($msg);
utf8::encode($msg);
my $pack = decode_json($msg);
my ($token, $payload) = #{$pack};
Logger::log(5, "Sending push with token: $token and Data: \n".Dumper($payload));
$apns->queue_notification(
$token,
$payload
);
$apns->send_queue;
}
So in the push subroutine I pass JSON data with the format given below. My problem is with the emoji character \x{2460}. You can see I added this line
utf8::encode($msg);
Before decoding the data. If I remove this line I get an error while decoding the JSON data
Wide character in subroutine entry at .....
With the above line added I can decode my JSON data. However when I try to write to the socket in the next line ($apns->send_queue) gives
Cannot decode string with wide characters at /usr/lib/perl/5.10/Encode.pm line 176
How do I solve this?
Message format (JSON)
["token",
{
"aps":{
"alert":"Alert: \x{2460}",
"content-available":1,
"badge":2,
"sound":"default.aiff"
},
"d":"Meta"
}
]
Dumper Output
[-] [ 2015-08-25T20:03:15 ] [APNS Client] Got message $VAR1 = "[\"19c360f37681035730a26cckjgkjgkj58b2d20326986f4265ee802c103f51\",{\"aps\":{\"alert\":\"Alert: \x{24bc}\",\"content-available\":1,\"badge\":2,\"sound\":\"default.aiff\"},\"d\":\"Meta\"}]";
[-] [ 2015-08-25T20:03:15 ] Sending push with token: 119c360f37681035730a26cckjgkjgkj58b2d20326986f4265ee802c103f51 and Data:
$VAR1 = {
'aps' => {
'alert' => "Alert: \x{24bc}",
'content-available' => 1,
'badge' => 2,
'sound' => 'default.aiff'
},
'd' => 'Meta'
};
[x] [ 2015-08-25T20:03:15 ] [APNS Client] Error writing to socket. Reconnecting : Cannot decode string with wide characters at /usr/lib/perl/5.10/Encode.pm line 176.

Answer 1

First of all, decode_json expects JSON encoded using UTF-8, so if you're starting with "decoded" JSON, it is proper to encode it as you did.
utf8::encode( my $json_utf8 = $json_uni );
my $data = decode_json($json_utf8);
However, it would have been simpler to use from_json.
my $data = from_json($json_uni);
Now on to your question. Whoever wrote Net::APNS::Persistent messed up big time. I looked at the source code, and they expect the alert message to be encoded using UTF-8. Adding the following will make your structure conform with the module's wonky expectation:
utf8::encode(
ref($payload->{aps}{alert}) eq 'HASH'
? $payload->{aps}{alert}{body}
: $payload->{aps}{alert}
);
It wouldn't surprise me if you ran into other issues. Notably, the modules uses the bytes module, a sure sign that something is being done incorrectly.

Answer 2

You probably have to UTF-8 encode the alert in $payload before sending it. You can also use from_json instead of decode_json to avoid the first encoding step:
sub push {
my $msg = $_[1];
Logger::log(5, "[APNS Client] Got message ".Dumper($msg));
my $pack = from_json($msg);
my ($token, $payload) = #{$pack};
Logger::log(5, "Sending push with token: $token and Data: \n".Dumper($payload));
# UTF-8 encode before sending.
utf8::encode($payload->{aps}{alert});
$apns->queue_notification(
$token,
$payload
);
$apns->send_queue;
}