perl使用socket 发送二进制数据

最近使用xml进行通讯，使用自定义的协议，最先发送xml文件的长度，然后是xml文件。
使用perl发送一个整数还是比较麻烦的，这和python一样，所以python 3才有了bytes字节类型。

use IO::Socket::INET;

# auto-flush on socket
$| = 1;

# create a connecting socket
my $socket = new IO::Socket::INET (
    PeerHost => '127.0.0.1',
    PeerPort => '3565',
    Proto => 'tcp',
);
die "cannot connect to the server $!\n" unless $socket;
print "connected to the server\n";

my $xml = <<"END_XML";

          
           
END_XML
my $size = length($xml);
# data to send to a server
my $req = 'hello world';
$size =pack("N",$size);
$size = $socket->send($size.$xml);

print "sent data of length $size\n";

# notify server that request has been sent
shutdown($socket, 1);

# receive a response of up to 1024 characters from server
my $response = "";
$socket->recv($response, 1024);
print "received response: $response\n";

$socket->close();

使用perl的pack处理，$size =pack("i",$size);使用小端字节序