Monitor a kickstarter

kickstarter.py

from bs4 import BeautifulSoup
from requests import get as http_get
from datetime import datetime
from time import sleep, perf_counter as now
import argparse


def get_properties(url):
    '''
    returns the number of backers, and total amount backed
    '''
    soup = BeautifulSoup(http_get(url).content)
    return (
        int(soup.find(itemprop='Project[backers_count]')
            .text.replace(',', '')),
        int(soup.find(itemprop='Project[pledged]')
            .text.lstrip('$').replace(',', '')))


def generate_properties(url, sleeptime):
    '''
    Repeatedly yield the properties (backers, pledged) of a kickstarter. Only
    yields when the properties change. Only poll the page every sleeptime
    seconds
    '''
    previous = None
    while True:
        start = now()
        prop = get_properties(url)
        if prop != previous:
            yield prop
            previous = prop
        sleep(max(0, sleeptime - (now() - start)))


parser = argparse.ArgumentParser(epilog='''This project lets you poll a
kickstarter project, to keep in touch with how it is doing. It polls every
''')
arg = parser.add_argument

arg('-f', '--freq', help="Frequency in seconds to poll for updates", type=float,
    default=60)
arg('url', help="URL of the Kickstarter project to poll")


def main(args):
    args = parser.parse_args(args[1:])
    for backers, pledge in generate_properties(args.url, args.freq):
        print(datetime.now().isoformat(), backers, pledge)


if __name__ == '__main__':
    from sys import argv
    main(argv)