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 3.4+ and PyPy. To install it,
use:
.. code-block:: bash
$ pip install html5lib
Optional Dependencies
The following third-party libraries may be used for additional
functionality:
-
datriecan be used under CPython to improve parsing performance
(though in almost all cases the improvement is marginal); -
lxmlis supported as a tree format (for both building and
walking) under CPython (but not PyPy where it is known to cause
segfaults); -
genshihas a treewalker (but not builder); and -
chardetcan 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 py.test 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?
There's a mailing list available for support on Google Groups,
html5lib-discuss <http://groups.google.com/group/html5lib-discuss>,
though you may get a quicker response asking on IRC in #whatwg on irc.freenode.net <http://wiki.whatwg.org/wiki/IRC>.