gistfile1.py

#!/usr/bin/python

"""
BART departure times from the command line. Use it like this:

bart # departure times for Powell St, POWL
bart 24th # departure times for 24th and Mission
bart nbrk # departure times for North Berkeley
"""

import sys
import optparse
from xml.dom import minidom
import urllib2

BART_DATA_URL = "http://www.bart.gov/dev/eta/bart_eta.xml"

abbr_to_name = \
{u'12TH': u'12th St. Oakland City Center',
 u'16TH': u'16th St. Mission',
 u'19TH': u'19th St. Oakland',
 u'24TH': u'24th St. Mission',
 u'ASHB': u'Ashby',
 u'BALB': u'Balboa Park',
 u'BAYF': u'Bay Fair',
 u'CAST': u'Castro Valley',
 u'CIVC': u'Civic Center',
 u'COLM': u'Colma',
 u'COLS': u'Coliseum/Oakland Airport',
 u'CONC': u'Concord',
 u'DALY': u'Daly City',
 u'DBRK': u'Downtown Berkeley',
 u'DELN': u'El Cerrito del Norte',
 u'DUBL': u'Dublin/Pleasanton',
 u'EMBR': u'Embarcadero',
 u'FRMT': u'Fremont',
 u'FTVL': u'Fruitvale',
 u'GLEN': u'Glen Park',
 u'HAYW': u'Hayward',
 u'LAFY': u'Lafayette',
 u'LAKE': u'Lake Merritt',
 u'MCAR': u'MacArthur',
 u'MLBR': u'Millbrae',
 u'MONT': u'Montgomery St.',
 u'NBRK': u'North Berkeley',
 u'NCON': u'North Concord/Martinez',
 u'ORIN': u'Orinda',
 u'PHIL': u'Pleasant Hill',
 u'PITT': u'Pittsburg/Bay Point',
 u'PLZA': u'El Cerrito Plaza',
 u'POWL': u'Powell St.',
 u'RICH': u'Richmond',
 u'ROCK': u'Rockridge',
 u'SANL': u'San Leandro',
 u'SBRN': u'San Bruno',
 u'SFIA': u"San Francisco Int'l Airport",
 u'SHAY': u'South Hayward',
 u'SSAN': u'South San Francisco',
 u'UCTY': u'Union City',
 u'WCRK': u'Walnut Creek',
 u'WOAK': u'West Oakland'}

def unpack_text(element, tagname):
	return element.getElementsByTagName(tagname)[0].firstChild.data

def get_station_to_status():
	doc = urllib2.urlopen(BART_DATA_URL)
	dom = minidom.parse(doc)

	max_dest_len = -1
	station_to_status = {}
	for elem in dom.documentElement.getElementsByTagName('station'):
		#station = elem.getElementsByTagName('abbr')[0].data
		try:
			station_abbr, _station_name, station_time = [unpack_text(elem, name) for name in ('abbr', 'name', 'time')]
		except AttributeError:
			#XXX sometimes the API returns a borked station, ignore
			continue

		record = {'station_abbr': station_abbr, 'time': station_time, 'eta': {}}

		for status in elem.getElementsByTagName('eta'):
			dest = unpack_text(status, 'destination')
			max_dest_len = max(max_dest_len, len(dest))
			estimate = unpack_text(status, 'estimate')
			estimate_pieces = [piece.split(" ")[0] for piece in estimate.split(", ")]
			estimate_times = [int(piece) if piece != "Leaving" else 0 for piece in estimate_pieces]
			record['eta'][dest] = estimate_times

		station_to_status[station_abbr] = record

	return station_to_status, max_dest_len

def main():
	parser = optparse.OptionParser(usage="usage: %prog STATION")
	(_options, args) = parser.parse_args()

	station = args[0].upper() if len(args) > 0 else 'POWL'
	humanreadable_station = abbr_to_name.get(station)
	if not humanreadable_station:
		print >>sys.stderr, "Unrecognized abbreviation %s." % (station,)
		return 1

	station_to_status, max_dest_len = get_station_to_status()
	status = station_to_status.get(station)
	if status is None:
		print "No departure times for %s available." % (humanreadable_station,)
		return 0

	print "Departure times for %s (as of %s)" % (humanreadable_station, status['time'])
	for dest, times in status['eta'].iteritems():
		print "%-*s  %s" % (max_dest_len, dest, " mins, ".join(str(time) for time in times) + " mins")
	return 0

if __name__ == '__main__':
	sys.exit(main())