Python URL path join

url-path-join.py

#!/usr/bin/env python3
# coding: utf8

import re
import urllib.parse

def url_path_join(base_url, *paths):
	parsed_url = urllib.parse.urlsplit(base_url)
	base_path = re.sub('/+', '/', parsed_url.path)
	if paths:
		if len(base_path) and base_path[-1] != '/':
			base_path += '/'
		for path in paths[:-1]:
			path = re.sub('/+', '/', path).lstrip('/') + '/'
			base_path = urllib.parse.urljoin(base_path, path)
		path = paths[-1]
		path = re.sub('/+', '/', path).lstrip('/')
		base_path = urllib.parse.urljoin(base_path, path)
	return urllib.parse.urlunsplit(parsed_url._replace(path=base_path))

# Some random tests
urls = [
	('http://example.com/relative/url/to/file',      'http://example.com',       'relative/url/to/file'      ),
	('http://example.com/relative/url/to/file',      'http://example.com/',      'relative/url/to/file'      ),
	('http://example.com/relative/url/to/file',      'http://example.com//',     'relative/url/to/file'      ),
	('http://example.com/relative/url/to/file',      'http://example.com/',      '/relative/url/to/file'     ),
	('http://example.com/relative/url/to/file',      'http://example.com/',      '../relative/url/to/file'   ),
	('http://example.com/relative/url/to/file',      'http://example.com/',      '/../relative/url/to/file'  ),
	('http://example.com/relative/url/to/file',      'http://example.com/base',  '../relative/url/to/file'   ),
	('http://example.com/relative/url/to/file',      'http://example.com/base/', '../relative/url/to/file'   ),
	('http://example.com/relative/url/to/file',      'http://example.com//base/', '../relative/url/to/file'  ),
	('http://example.com/relative/url/to/file/',     'http://example.com/base//', '../relative/url/to/file/' ),
	('http://example.com/relative/url/to/file',      'http://example.com/base',  '/../relative/url/to/file'  ),
	('http://example.com/relative/url/to/file',      'http://example.com/base/', '/../relative/url/to/file'  ),
	('http://example.com/relative/url/to/file/',     'http://example.com/base/', '/../relative/url/to/file/' ),
	('http://example.com/base/relative/url/to/file', 'http://example.com/base',  '/relative/url/to/file'     ),
	('http://example.com/base/relative/url/to/file', 'http://example.com/base/', '/relative/url/to/file'     ),
	('http://example.com/base/relative/url/to/file', 'http://example.com/base',  'relative/url/to/file'      ),
	('http://example.com/base/relative/url/to/file', 'http://example.com/base/', '//relative//url//', '/to/file'  ),
	('http://example.com/base/relative/url/to/my/file', 'http://example.com/base/', 'relative/url', '/to/', 'my/file'  ),
	('http://example.com/base/relative/url/to/my/file/', 'http://example.com/base/', 'relative/url', '/to/', 'my/file/'  ),
	('http://example.com/base/relative/url/to/file?a=a/b/c#here', 'http://example.com/base/', 'relative//url', '//to//file?a=a/b/c#here' ),
	('https://username:password@example.com:8443/base/relative/url/to/new/path/to/file/?a=a/b/c&b=//d//e//f//#here', 'https://username:password@example.com:8443/base/relative/url/to/file?a=a/b/c&b=//d//e//f//#here', '//..//new//path//', '//to//file//')
]

def test(func):
	counter = 0
	for joined_url, base_url, *relative_urls in urls:
		print("Test {num}:".format(num=counter))
		print("Base URL    : '{url}'".format(url=base_url))
		print("Relative URL: '{url}'".format(url=relative_urls))
		computed_url = func(base_url, *relative_urls)
		print("Computed URL: {url}".format(url=computed_url))
		print("Joined URL  : {url}".format(url=joined_url))
		assert computed_url == joined_url
		counter += 1

test(url_path_join)