PHP and Python unpack return different results from same source

Question

I cannot seem to get even vaguely the same data from the Python (Which I would prefer to use) and PHP (Which works fine, coded by the host of the website) scripts.

PHP connects to the same location as the Python script.

And before anyone jumps the gun, I know the python script only retrieves a part of the data. But I can't get even vaguely the same data from the server.

Python:

import socket, struct

host,port = 'baystation12.net', 8000
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((host, port))
s.send('status\r\n')
data = s.recv(1024)
s.close()
print 'Received:', repr(data) # >>> Received: '\x00\xc7\x00\x07\x02\xadj\x00\x00\x1c\xf6'
cache,form,listy = "",">H",[]
for i in data:
    if cache != "":
        listy.append(struct.unpack(form,cache+i))
    else:
        cache = i
print "Unpacked:",listy # >>> Unpacked: [(199,), (0,), (7,), (2,), (173,), (106,), (0,), (0,), (28,), (246,)]


text = ""
for i in listy:
    text += chr(i[0])
print "Text:",text # >>> Text: Ç
#Shows up incorrectly when I try to copy it.

PHP:

#!/usr/bin/php
<?php
function export($addr,$port,$str)
{
    if($str{0} != "?") $str = ("?" . $str);
    $query = "\x00\x83" . pack("n",strlen($str)+6) . "\x00\x00\x00\x00\x00" . $str . "\x00";
    $server = socket_create(AF_INET,SOCK_STREAM,SOL_TCP) or exit('Unable to create export socket; ' . socket_strerror(socket_last_error()));
    socket_connect($server,$addr,$port) or exit('Unable to establish socket connection; ' . socket_strerror(socket_last_error()));
    $bytessent = 0;
    while($bytessent < strlen($query))
    {
        $result = socket_write($server,substr($query,$bytessent),strlen($query)-$bytessent);
        if($result === FALSE) return('Unable to transfer requested data; ' .  socket_strerror(socket_last_error()));
        $bytessent += $result;
    }
    $resbuf = '';
    while( socket_recv($server, $message,1,0 )){
       $resbuf .= $message;
    if(strpos($resbuf,"&end")!=FALSE)
      {
       echo $resbuf;
       socket_close($server);
       return($resbuf);
      }
    echo $message;
    };
    echo $resbuf."\n";
    socket_close($server);
}
export("localhost","8000","status");
?>

PHP's output:

version=Baystation+12&mode=extended&respawn=0&enter=1&vote=1&ai=1&host&players=5&player0=CompactNinja&player1=Sick+trigger&player2=SweetJealousy&player3=Cacophony&player4=Anchorshag&end

Any idea why Python gives out nonsensical characters when unpacking the data, while PHP gives out the above.

Answer 1

You're not sending the same query to your server in python.

In python you're sending status

In PHP you're sending something like \\x00\\x83\\x00\\x0d\\x00\\x00\\x00\\x00\\x00\\x00?status\\x00

If you change your python to more closely imitate the PHP then it works a lot better:

import socket, struct

host,port = 'baystation12.net', 8000
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((host, port))

senddata = "?status"
query  = '\x00\x83' + struct.pack(">H", len(senddata)+6) + '\x00'*5 + senddata + '\x00'
s.send(query)

data = s.recv(1024)
print `data`

When I tried that, it printed

'\x00\x83\x00\xe9\x06version=Baystation+12&mode=traitor&respawn=0&enter=1&vote=1&ai=1&host&players=7&player0=Kosherman&player1=Ghazkull&player2=Doug+H.+Nuts&player3=Lord+Braindead&player4=KirbyElder&player5=Master+of+Apples&player6=Cacophony&end=%23end\x00'

Which looks pretty similar to what the PHP was getting.

Answer 2

Try listy.append(struct.unpack(form,cache+i)[0])

You're ending up with a list of 1-element tuples rather than the a list of numbers.

From the docs: http://docs.python.org/library/struct.html#struct.unpack

 struct.unpack(fmt, string) 

Unpack the string (presumably packed by pack(fmt, ...)) according to the given format. The result is a tuple even if it contains exactly one item. The string must contain exactly the amount of data required by the format (len(string) must equal calcsize(fmt)).