publicsuffixlist
Public Suffix List parser implementation for Python 3.5+.
- Compliant with TEST DATA
- Supports IDN (unicode and punycoded).
- Supports Python3.5+
- Shipped with built-in PSL and an updater script.
- Written in Pure Python with no library dependencies.
Install
publicsuffixlist can be installed via pip.
$ pip install publicsuffixlist
Usage
Basic Usage:
from publicsuffixlist import PublicSuffixList
psl = PublicSuffixList()
# Uses built-in PSL file
print(psl.publicsuffix("www.example.com")) # "com"
# the longest public suffix part
print(psl.privatesuffix("www.example.com")) # "example.com"
# the shortest domain assigned for a registrant
print(psl.privatesuffix("com")) # None
# Returns None if no private (non-public) part found
print(psl.publicsuffix("www.example.unknownnewtld")) # "unknownnewtld"
# New TLDs are valid public suffix by default
print(psl.publicsuffix("www.example.香港")) #"香港"
# Accepts unicode
print(psl.publicsuffix("www.example.xn--j6w193g")) # "xn--j6w193g"
# Accepts Punycode IDNs by default
print(psl.privatesuffix("WWW.EXAMPLE.COM")) # "example.com"
# Returns in lowercase by default
print(psl.privatesuffix("WWW.EXAMPLE.COM", keep_case=True) # "EXAMPLE.COM"
# kwarg `keep_case=True` to disable the case conversion
The latest PSL is packaged once a day. If you need to parse your own version,
it can be passed as a file-like iterable object, or just a str:
with open("latest_psl.dat", "rb") as f:
psl = PublicSuffixList(f)
The unittest and PSL updater can be invoked as module.
$ python -m publicsuffixlist.test
$ python -m publicsuffixlist.update
Additional convenient methods:
print(psl.is_private("example.com")) # True
print(psl.is_public("example.com")) # False
print(psl.privateparts("aaa.www.example.com")) # ("aaa", "www", "example.com")
print(psl.subdomain("aaa.www.example.com", depth=1)) # "www.example.com"
Limitation
Domain Label Validation
publicsuffixlist do NOT provide domain name and label validation.
In the DNS protocol, most 8-bit characters are acceptable as labels of domain
names. While ICANN-compliant registries do not accept domain names containing
underscores (_), hostnames may include them. For example, DMARC records can
contain underscores. Users must confirm that the input domain names are valid
based on their specific context.
Punycode Handling
Partially encoded (Unicode-mixed) Punycode is not supported due to very slow
Punycode encoding/decoding and unpredictable encoding results. If you are
unsure whether an input is valid Punycode, you should use:
unknowndomain.encode("idna").decode("ascii"). This method, converting to idna
is idempotent.
Handling Arbitrary Binary
If you need to accept arbitrary or malicious binary data, it can be passed as a tuple of bytes. Note that the returned bytes may include byte patterns that cannot be decoded or represented as a standard domain name. Example:
psl.privatesuffix((b"a.a", b"a.example\xff", b"com")) # (b"a.example\xff", b"com")
# Note that IDNs must be punycoded when passed as tuple of bytes.
psl = PublicSuffixList("例.example")
psl.publicsuffix((b"xn--fsq", b"example")) # (b"xn--fsq", b"example")
# UTF-8 encoded bytes of "例" do not match.
psl.publicsuffix((b"\xe4\xbe\x8b", b"example")) # (b"example",)
License
- This module is licensed under Mozilla Public License 2.0.
- The Public Suffix List maintained by the Mozilla Foundation is licensed under the Mozilla Public License 2.0.
- The PSL testcase dataset is in the public domain (CC0).
Development / Packaging
This module and its packaging workflow are maintained in the author's repository located at https://github.com/ko-zu/psl.
A new package, which includes the latest PSL file, is automatically generated
and uploaded to PyPI. The last part of the version number represents the
release date. For example, 0.10.1.20230331 indicates a release date of March
31, 2023.
This package dropped support for Python 2.7 and Python 3.4 or prior versions at the version 1.0.0 release in June 2024. The last version that works on Python 2.x is 0.10.0.x.
Source / Link
- GitHub repository: (https://github.com/ko-zu/psl)
- PyPI: (https://pypi.org/project/publicsuffixlist/)
1 maintainer
Release files for publicsuffixlist 1.0.2.20250606
For a detailed explanation of source distributions (sdists) and built distributions (wheels), please see the package formats documentation.
Source distribution (sdist)
| File | Size | Uploaded | |
|---|---|---|---|
| publicsuffixlist-1.0.2.20250606.tar.gz | 105.4 kB | Details |
Built distribution (wheel)
| File | Interpreter | ABI | Platform | Reset |
|---|---|---|---|---|
| publicsuffixlist-1.0.2.20250606-py2.py3-none-any.whl | Python 2, Python 3 | none | any | Details |
Total release size: 210.5 kB
Release files / publicsuffixlist-1.0.2.20250606.tar.gz
| Download URL | publicsuffixlist-1.0.2.20250606.tar.gz |
|---|---|
| Size | 105.4 kB |
| Tags | Source |
|
SHA-256 checksum How to use checksums |
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Release files / publicsuffixlist-1.0.2.20250606-py2.py3-none-any.whl
| Download URL | publicsuffixlist-1.0.2.20250606-py2.py3-none-any.whl |
|---|---|
| Size | 105.1 kB |
| Tags | Python 2 Python 3 |
|
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