Unit 2: Source Code

from urllib.request import urlopen


def get_page(url):
    return str(urlopen(url).read())


def get_next_target(page):
    start_link = page.find('< a href=')
    if start_link == -1:
        return None, 0

    start_quote = page.find('"', start_link)
    end_quote = page.find('"', start_quote + 1)
    url = page[start_quote + 1:end_quote]
    return url, end_quote


def print_all_links(page):
    while True:
        url, endpos = get_next_target(page)
        if url:
            print(url)
            page = page[endpos:]
        else:
            break