Mt. Gox live trade watcher

mtgox.pl

#!/usr/bin/perl -w

# Donations may be sent to 1Ni6BojkPJ62HvCrdx4LQRrgvNKg56yq3y
#
# Copyright (C) 2011 by Chris Howie <me@chrishowie.com>
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

use strict;
use IO::Socket::INET;
use JSON;

$| = 1;

my $socket = new IO::Socket::INET(
    PeerAddr    => 'websocket.mtgox.com',
    PeerPort    => 80,
    Proto       => 'tcp')
        or die 'Unable to connect';

binmode $socket;

print $socket <<REQUEST;
GET /mtgox HTTP/1.1\r
Upgrade: WebSocket\r
Connection: Upgrade\r
Host: websocket.mtgox.com\r
Origin: null\r
\r
REQUEST

$socket->flush();

my $line;
do {
    $line = <$socket>;
    if (defined($line)) {
        $line =~ s/\r//g;
        print $line;
    }
} while (defined($line) and $line !~ /^$/m);

my $buffer = '';
my $char;

while (read($socket, $char, 1)) {
    if ($char eq "\xff") {
        &display_event(decode_json($buffer));
        $buffer = '';
    } elsif ($char ne "\0") {
        $buffer .= $char;
    }
}

$socket->close();

sub display_event ($) {
    my $event = shift;

    if ($event->{'channel'} ne 'dbf1dee9-4f2e-4a08-8cb7-748919a71b21') {
        return;
    }

    my $trade = $event->{'trade'};

    return unless defined($trade);

    my $time = localtime($trade->{'date'});

    printf "%s -- %11.5f %3s @ %11.5f %3s\n",
        $time,
        $trade->{'amount'}, $trade->{'item'},
        $trade->{'price'}, $trade->{'price_currency'};
}