News You Can Bruise for 2012 February 8

Beautiful Soup 4 beta 4 is out! You can install it with easy_install beautifulsoup4 or pip install beautifulsoup4. You can also download the tarball or check out the Bazaar repository.

Big changes:

• If you're using Python 3.2, the built-in html.parser is now reliable enough to use on its own. You don't need to install lxml or html5lib just to parse bad HTML (but lxml is still a lot faster). The forthcoming Python 2.7.3 should also work this way.

  This is of course a feature of Python, but due to a pretty bad bug in html.parser, I wasn't taking advantage of it. I worked with Ezio Melotti to monkeypatch that bug from within BS, and now we're back in the very good situation of not needing any external dependencies.

• new_tag() will follow the rules of whatever tree builder was used to create the original soup. For example, a new <p> tag will look like "<p />" if you're dealing with XML, but it'll look like "<p></p>" if you're dealing with HTML.
• There's now a new_string() method to go along with new_tag().
• There are two new methods for manipulating the tree: PageElement.insert_before() and PageElement.insert_after().
• I replaced the substitute_html_entities argument with the more general formatter argument. You can do all sorts of crazy stuff with this.
• The default formatter converts bare ampersands and angle brackets to XML entities, but doesn't touch HTML entities. I think it's kind of America-centric to convert characters like é to &eacute; by default, but I might make the default a "punctuation" formatter that converts things like curly quotes to HTML entities.