A Python script to fetch info from an URL (Regular expression matching)

#!/usr/bin/python -tt

# A script to get specified info from a URL
# Author Ando Roots 2010
# Usage: Specify the parameters with command line options.
# Usage: ./fetch_info.py URL Search_pattern_start Search_pattern_end
# EXAMPLE: Rate.ee number of online users
# ./fetch_info.py http://www.rate.ee/ 'amp;act=search"&gt;<strong>' ' &amp;raquo;</strong>'

import sys
import urllib
import re

# Fetch the souce code, find and print the information
def fetch_info(url, start, end):

  sourceCode = urllib.urlopen(url).read()
  expression = start + '(.*?)' + end

  # Regular expression matching on the source code of the target URL
  match = re.compile(expression).search(sourceCode)
  if match:
    print match.group(1)
  else:
    print 'Did not find a match.'
  sys.exit(0)

def main():
  if len(sys.argv) != 4:
    print 'A script to get specified info from a URL by A. Roots'
    print 'Usage: ./fetch_info.py URL Search_pattern_start Search_pattern_end'
    sys.exit(1)

  fetch_info(sys.argv[1], sys.argv[2], sys.argv[3])
  sys.exit(0)

if __name__ == '__main__':
  main()