HP Touchpad tracker

touchpad.py

import urllib2
from lxml import html
from time import sleep
from datetime import datetime
from subprocess import Popen 

PRODUCT_URL = "http://www.shopping.hp.com/store/product/product_detail/FB355UA%2523ABA?jumpid=se_r1002_fp_usen_hho"

def check():
    """
    Check product url and look for 'Out of Stock' in the specified xpath.
    If not found, then the product maybe in stock, so BEEP.
    """   
    time_check = datetime.now()

    page = urllib2.urlopen(PRODUCT_URL).read()
    tree = html.fromstring(page)

    available = tree.xpath("//div//span[@class='error']/b")[0]

    is_available = not available.text.lower() == 'out of stock'
    
    if is_available:
       print time_check, "Touchpad maybe available"
       #Show a zenity popup
       Popen("zenity --info --text 'HP Touchpad maybe available'", shell=True) 
           
    else:
        print time_check, "Touch pad is not available"

def main():
    while True:
        check()
        sleep(120)

if __name__ == '__main__':
    main()