def shorten(url):
"""Shortens a given URL, returning the unique id of that URL
:url: a valid URL string
The URL will be recorded in the database if it does not already exist.
Returns a string id composed of lowercase alphanumeric characters
"""
existing_url = rdb.get('urls|' + url)
if existing_url:
return existing_url
else:
counter = rdb.incr('url_counter')
short = int_to_base36(counter)
rdb.set('urls|' + url, short)
rdb.set('shorts|' + short, url)
return short
def test_shorten_doesnt_exist_creates_new_next(self):
rdb.set('url_counter', 51)
shorten(TEST_URL)
self.assertEqual(rdb.get('urls|' + TEST_URL), '1g')
self.assertEqual(rdb.get('shorts|1g'), TEST_URL)
def test_shorten_doesnt_exist_creates_new(self):
with self.assertRaises(KeyError):
rdb['urls|' + TEST_URL]
shorten(TEST_URL)
self.assertEqual(rdb.get('urls|' + TEST_URL), '1')
self.assertEqual(rdb.get('shorts|1'), TEST_URL)
def test_shorten_doesnt_exist_returns_valid(self):
self.assertIsNone(rdb.get('urls|' + TEST_URL))
self.assertEqual(shorten(TEST_URL), '1')
