#!/usr/bin/env python
# Distance Module
# by Pravin Paratey (pravinp at gmail dot com)
# Code is licenced under Creative Commons Attribution-Noncommercial-Share Alike 2.5 India
# http://creativecommons.org/licenses/by-nc-sa/2.5/in/
 
import urllib2, cgi, re
from math import sqrt
 
class Distance:
    """
    Using yahoo maps api (http://developer.yahoo.com/maps/rest/V1/geocode.html), 
    this class is responsible for returning the euclidean distance between
    two places
    """
    def getDistance(self, start, end):
        """ Gets the euclidean distance between start and end """
        (start_x, start_y) = self.getCoords(start)
        (end_x, end_y) = self.getCoords(end)
        # 1 degree = 111.12 kms or 69.047 miles
        return sqrt((start_x - end_x) ** 2 + (start_y - end_y) ** 2) * 111.12
 
 
    def getCoords(self, location):
        """ Gets the co-ordinates for the given location """
        url = 'http://local.yahooapis.com/MapsService/V1/geocode?appid=' + 
                API_KEY + '&street=' + urllib2.quote(location)
        response = urllib2.urlopen(url)
        (x, y) = self._parseXML(response.read())
        return float(x), float(y)
 
 
    def _parseXML(self, xml):
        """ Parses XML and returns latitude and longitude """
        m = re.findall('<Latitude>(\d+.\d+)</Latitude><Longitude>(\d+.\d+)</Longitude>', xml)
        # In case of multiple matches, return 1st match
        return m[0]
 
if __name__ == '__main__':
    d = Distance()
    print 'Distance in kms: '
    print d.getDistance("Hiranandani, Powai, Mumbai", "Dadar Station, Mumbai")