mwparserfromhell/README.rst

mwparserfromhell
================

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**mwparserfromhell** (the *MediaWiki Parser from Hell*) is a Python package
that provides an easy-to-use and outrageously powerful parser for MediaWiki_
wikicode. It supports Python 2 and Python 3.

Developed by Earwig_ with contributions from `Σ`_, Legoktm_, and others.
Full documentation is available on ReadTheDocs_. Development occurs on GitHub_.

Installation
------------

The easiest way to install the parser is through the `Python Package Index`_;
you can install the latest release with ``pip install mwparserfromhell``
(`get pip`_). On Windows, make sure you have the latest version of pip
installed by running ``pip install --upgrade pip``.

Alternatively, get the latest development version::

    git clone https://github.com/earwig/mwparserfromhell.git
    cd mwparserfromhell
    python setup.py install

You can run the comprehensive unit testing suite with
``python setup.py test -q``.

Usage
-----

Normal usage is rather straightforward (where ``text`` is page text)::

    >>> import mwparserfromhell
    >>> wikicode = mwparserfromhell.parse(text)

``wikicode`` is a ``mwparserfromhell.Wikicode`` object, which acts like an
ordinary ``str`` object (or ``unicode`` in Python 2) with some extra methods.
For example::

    >>> text = "I has a template! {{foo|bar|baz|eggs=spam}} See it?"
    >>> wikicode = mwparserfromhell.parse(text)
    >>> print(wikicode)
    I has a template! {{foo|bar|baz|eggs=spam}} See it?
    >>> templates = wikicode.filter_templates()
    >>> print(templates)
    ['{{foo|bar|baz|eggs=spam}}']
    >>> template = templates[0]
    >>> print(template.name)
    foo
    >>> print(template.params)
    ['bar', 'baz', 'eggs=spam']
    >>> print(template.get(1).value)
    bar
    >>> print(template.get("eggs").value)
    spam

Since nodes can contain other nodes, getting nested templates is trivial::

    >>> text = "{{foo|{{bar}}={{baz|{{spam}}}}}}"
    >>> mwparserfromhell.parse(text).filter_templates()
    ['{{foo|{{bar}}={{baz|{{spam}}}}}}', '{{bar}}', '{{baz|{{spam}}}}', '{{spam}}']

You can also pass ``recursive=False`` to ``filter_templates()`` and explore
templates manually. This is possible because nodes can contain additional
``Wikicode`` objects::

    >>> code = mwparserfromhell.parse("{{foo|this {{includes a|template}}}}")
    >>> print(code.filter_templates(recursive=False))
    ['{{foo|this {{includes a|template}}}}']
    >>> foo = code.filter_templates(recursive=False)[0]
    >>> print(foo.get(1).value)
    this {{includes a|template}}
    >>> print(foo.get(1).value.filter_templates()[0])
    {{includes a|template}}
    >>> print(foo.get(1).value.filter_templates()[0].get(1).value)
    template

Templates can be easily modified to add, remove, or alter params. ``Wikicode``
objects can be treated like lists, with ``append()``, ``insert()``,
``remove()``, ``replace()``, and more. They also have a ``matches()`` method
for comparing page or template names, which takes care of capitalization and
whitespace::

    >>> text = "{{cleanup}} '''Foo''' is a [[bar]]. {{uncategorized}}"
    >>> code = mwparserfromhell.parse(text)
    >>> for template in code.filter_templates():
    ...     if template.name.matches("Cleanup") and not template.has("date"):
    ...         template.add("date", "July 2012")
    ...
    >>> print(code)
    {{cleanup|date=July 2012}} '''Foo''' is a [[bar]]. {{uncategorized}}
    >>> code.replace("{{uncategorized}}", "{{bar-stub}}")
    >>> print(code)
    {{cleanup|date=July 2012}} '''Foo''' is a [[bar]]. {{bar-stub}}
    >>> print(code.filter_templates())
    ['{{cleanup|date=July 2012}}', '{{bar-stub}}']

You can then convert ``code`` back into a regular ``str`` object (for
saving the page!) by calling ``str()`` on it::

    >>> text = str(code)
    >>> print(text)
    {{cleanup|date=July 2012}} '''Foo''' is a [[bar]]. {{bar-stub}}
    >>> text == code
    True

Likewise, use ``unicode(code)`` in Python 2.

Integration
-----------

``mwparserfromhell`` is used by and originally developed for EarwigBot_;
``Page`` objects have a ``parse`` method that essentially calls
``mwparserfromhell.parse()`` on ``page.get()``.

If you're using Pywikibot_, your code might look like this::

    import mwparserfromhell
    import pywikibot

    def parse(title):
        site = pywikibot.Site()
        page = pywikibot.Page(site, title)
        text = page.get()
        return mwparserfromhell.parse(text)

If you're not using a library, you can parse any page using the following code
(via the API_)::

    import json
    from urllib.parse import urlencode
    from urllib.request import urlopen
    import mwparserfromhell
    API_URL = "http://en.wikipedia.org/w/api.php"

    def parse(title):
        data = {"action": "query", "prop": "revisions", "rvlimit": 1,
                "rvprop": "content", "format": "json", "titles": title}
        raw = urlopen(API_URL, urlencode(data).encode()).read()
        res = json.loads(raw)
        text = res["query"]["pages"].values()[0]["revisions"][0]["*"]
        return mwparserfromhell.parse(text)

.. _MediaWiki:              http://mediawiki.org
.. _ReadTheDocs:            http://mwparserfromhell.readthedocs.org
.. _Earwig:                 http://en.wikipedia.org/wiki/User:The_Earwig
.. _Σ:                      http://en.wikipedia.org/wiki/User:%CE%A3
.. _Legoktm:                http://en.wikipedia.org/wiki/User:Legoktm
.. _GitHub:                 https://github.com/earwig/mwparserfromhell
.. _Python Package Index:   http://pypi.python.org
.. _get pip:                http://pypi.python.org/pypi/pip
.. _EarwigBot:              https://github.com/earwig/earwigbot
.. _Pywikibot:              https://www.mediawiki.org/wiki/Manual:Pywikibot
.. _API:                    http://mediawiki.org/wiki/API