html5lib

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html5lib is a pure-python library for parsing HTML. It is designed to
conform to the WHATWG HTML specification, as is implemented by all major
web browsers.

Usage

Simple usage follows this pattern:

… code-block:: python

import html5lib
with open(“mydocument.html”, “rb”) as f:
document = html5lib.parse(f)

or:

… code-block:: python

import html5lib
document = html5lib.parse(“

Hello World!”)

By default, the document will be an xml.etree element instance.
Whenever possible, html5lib chooses the accelerated ElementTree
implementation (i.e. xml.etree.cElementTree on Python 2.x).

Two other tree types are supported: xml.dom.minidom and
lxml.etree. To use an alternative format, specify the name of
a treebuilder:

… code-block:: python

import html5lib
with open(“mydocument.html”, “rb”) as f:
lxml_etree_document = html5lib.parse(f, treebuilder=“lxml”)

When using with urllib2 (Python 2), the charset from HTTP should be
pass into html5lib as follows:

… code-block:: python

from contextlib import closing
from urllib2 import urlopen
import html5lib

with closing(urlopen(“http://example.com/”)) as f:
document = html5lib.parse(f, transport_encoding=f.info().getparam(“charset”))

When using with urllib.request (Python 3), the charset from HTTP
should be pass into html5lib as follows:

… code-block:: python

from urllib.request import urlopen
import html5lib

with urlopen(“http://example.com/”) as f:
document = html5lib.parse(f, transport_encoding=f.info().get_content_charset())

To have more control over the parser, create a parser object explicitly.
For instance, to make the parser raise exceptions on parse errors, use:

… code-block:: python

import html5lib
with open(“mydocument.html”, “rb”) as f:
parser = html5lib.HTMLParser(strict=True)
document = parser.parse(f)

When you’re instantiating parser objects explicitly, pass a treebuilder
class as the tree keyword argument to use an alternative document
format:

… code-block:: python

import html5lib
parser = html5lib.HTMLParser(tree=html5lib.getTreeBuilder(“dom”))
minidom_document = parser.parse(“

Hello World!”)

More documentation is available at https://html5lib.readthedocs.io/.

Installation

html5lib works on CPython 2.7+, CPython 3.5+ and PyPy. To install:

… code-block:: bash

$ pip install html5lib

The goal is to support a (non-strict) superset of the versions that pip supports <https://pip.pypa.io/en/stable/installing/#python-and-os-compatibility>_.

Optional Dependencies

The following third-party libraries may be used for additional
functionality:

• lxml is supported as a tree format (for both building and
  walking) under CPython (but not PyPy where it is known to cause
  segfaults);

• genshi has a treewalker (but not builder); and

• chardet can be used as a fallback when character encoding cannot
  be determined.

Bugs

Please report any bugs on the issue tracker <https://github.com/html5lib/html5lib-python/issues>_.

Tests

Unit tests require the pytest and mock libraries and can be
run using the pytest command in the root directory.

Test data are contained in a separate html5lib-tests <https://github.com/html5lib/html5lib-tests>_ repository and included
as a submodule, thus for git checkouts they must be initialized::

$ git submodule init
$ git submodule update

If you have all compatible Python implementations available on your
system, you can run tests on all of them using the tox utility,
which can be found on PyPI.

Questions?

Check out the docs <https://html5lib.readthedocs.io/en/latest/>. Still
need help? Go to our GitHub Discussions <https://github.com/html5lib/html5lib-python/discussions>.

You can also browse the archives of the html5lib-discuss mailing list <https://www.mail-archive.com/[email protected]/>_.