The urlib.parse module in Python does not follow the legacy RFC 3978 standard nor does it follow the newer WHATWG URL specification. It is also relatively slow.

This is ada_url, a fast standard-compliant Python library for working with URLs based on the Ada URL parser.

• Documentation
• Development
• Ada

Install from PyPI:

pip install ada_url

The URL class is intended to match the one described in the WHATWG URL spec:.

>>> from ada_url import URL
>>> urlobj = URL('https://example.org/path/../file.txt')
>>> urlobj.href
'https://example.org/path/file.txt'

The parse_url function returns a dictionary of all URL elements:

>>> from ada_url import parse_url
>>> parse_url('https://user:pass@example.org:80/api?q=1#2')
{
    'href': 'https://user:pass@example.org:80/api?q=1#2',
    'username': 'user',
    'password': 'pass',
    'protocol': 'https:',
    'port': '80',
    'hostname': 'example.org',
    'host': 'example.org:80',
    'pathname': '/api',
    'search': '?q=1',
    'hash': '#2',
    'origin': 'https://example.org:80',
    'host_type': <HostType.DEFAULT: 0>,
    'scheme_type': <SchemeType.HTTPS: 2>
}

Replacing URL components with the URL class:

>>> from ada_url import URL
>>> urlobj = URL('https://example.org/path/../file.txt')
>>> urlobj.host = 'example.com'
>>> urlobj.href
'https://example.com/file.txt'

Replacing URL components with the replace_url function:

>>> from ada_url import replace_url >>> replace_url('https://example.org/path/../file.txt', host='example.com') 'https://example.com/file.txt'

The URLSearchParams class is intended to match the one described in the WHATWG URL spec.

>>> from ada_url import URLSearchParams
>>> obj = URLSearchParams('key1=value1&key2=value2')
>>> list(obj.items())
[('key1', 'value1'), ('key2', 'value2')]

The parse_search_params function returns a dictionary of search keys mapped to value lists:

>>> from ada_url import parse_search_params
>>> parse_search_params('key1=value1&key2=value2')
{'key1': ['value1'], 'key2': ['value2']}

The idna class can encode and decode IDNs:

>>> from ada_url import idna
>>> idna.encode('Bücher.example')
b'xn--bcher-kva.example'
>>> idna.decode(b'xn--bcher-kva.example')
'bücher.example'

This library is compliant with the WHATWG URL spec. This means, among other things, that it properly encodes IDNs and resolves paths:

>>> from ada_url import URL
>>> parsed_url = URL('https://www.GOoglé.com/./path/../path2/')
>>> parsed_url.hostname
'www.xn--googl-fsa.com'
>>> parsed_url.pathname
'/path2/'

Contrast that with the Python standard library's urlib.parse module:

>>> from urllib.parse import urlparse
>>> parsed_url = urlparse('https://www.GOoglé.com/./path/../path2/')
>>> parsed_url.hostname
'www.googlé.com'
>>> parsed_url.path
'/./path/../path2/'

This package uses CFFI to call the Ada library's functions, which has a performance cost. The alternative can_ada (Canadian Ada) package uses pybind11 to generate a Python extension module, which is more performant.