busstop.py

import urlparse

from gevent.pywsgi import WSGIServer
import jinja2
from lxml import etree
import requests


BASE_URL = (
    'http://old.mybustracker.co.uk/getBusStopDepartures.php'
    '?refreshCount=0&clientType=b&busStopCode=%s&busStopDay=0&busStopService=0'
    '&numberOfPassage=2&busStopTime=&busStopDestination=0')


jenv = jinja2.Environment(loader=jinja2.FileSystemLoader('templates/'))


def query_string(environ, qs, default=None):
    query_string = urlparse.parse_qs(environ.get('QUERY_STRING', ''))
    return query_string.get(qs, default)


def fetch_feed(bus_stop_code):
    response = requests.post(BASE_URL % (bus_stop_code, ))
    return response.text


def parse_feed_data(feed_data):
    cleaned_data = feed_data\
        .replace('<?xml version="1.0" encoding="iso-8859-1"?>', '')\
        .replace('xmlns', 'xmlnamespace')
    root = etree.fromstring(cleaned_data)

    arrivals = []

    for row in root.findall('.//pre'):
        text = ''.join(row.xpath("./text()"))
        line = text.strip().split()
        service, time = line[0], line[-1]
        if time == 'DUE':
            time = '00'
        if len(time) == 1:
            time = '0' + time
        arrivals.append((service, time, ))

    return arrivals


def time_comparator(a, b):
    a = a.strip('*')
    b = b.strip('*')
    if ':' in a and ':' in b:
        return cmp(a, b)
    if ':' in a:
        return 1
    if ':' in b:
        return -1
    return cmp(a, b)


def csv_formatter(arrivals):
    r = []
    if arrivals:
        r.append('Serv,Time')

    for serv, time in sorted(
            arrivals, cmp=lambda a, b: time_comparator(a[1], b[1])):
        if ':' not in time:
            if time == '00':
                time = 'Due'
            else:
                time += 'mins'
        r.append(','.join([serv, time]))
    return '\n'.join(r)


def html_formatter(title, arrivals):
    data = []

    for serv, time in sorted(
            arrivals, cmp=lambda a, b: time_comparator(a[1], b[1])):
        colour = '999'
        try:
            time_int = int(time, 10)
            if time_int <= 5:
                colour = 'f33'
            elif time_int <= 10:
                colour = 'f93'
        except:
            pass
        if ':' not in time:
            if time == '00':
                time = 'Due'
            else:
                time += ' mins'

        data.append((colour, serv, time, ))

    return jenv.get_template('busstop.html').render(
        title=title, data=data).encode()


def application(environ, start_response):
    status = '200 OK'

    headers = [
        ('Content-Type', 'text/html')
    ]

    path = environ.get('PATH_INFO').strip('/')
    code, fmt = path.split('.')
    title = query_string(environ, 'title')

    start_response(status, headers)

    formatters = {
        'csv': csv_formatter,
        'html': lambda d: html_formatter(title, d),
    }

    formatter = formatters.get(fmt)

    if formatter:
        yield formatter(parse_feed_data(fetch_feed(code)))

    yield ''


if __name__ == '__main__':
    server = WSGIServer(('', 8000, ), application)
    server.serve_forever()