Get URLs from a page - Python

getLinks.py

#!/usr/bin/python
import urllib

def get_page(url):
	if(url):
 	       return urllib.urlopen(url).read()
	else:
		return ''

def get_next_url(page):
	pre_link = page.find('<a href=')
	if pre_link == -1:
		return None,0
	pre_quote = page.find('"',pre_link)
	post_quote = page.find('"', pre_quote+1)
	url = page[pre_quote+1:post_quote]
	return url, post_quote

def print_all_pages(page):
	while True:
		url, endpos = get_next_url(page)
		if url:
			if url.find('http') == 0:
				print url
			page = page[endpos:]
		else:
			break
      
print_all_pages(get_page('http://xkcd.com/353')) #Dynamically pass a page here