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Thursday, October 8, 2015
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Today I did :ticket:`522` in only one hour...

...except that I got stuck on a stupid detail for another couple of
hours.  In :meth:`CommentsByController.get_slave_summary
<lino.modlib.comments.models.CommentsByController.get_slave_summary>`
I now generate an overview of all comments. Since this includes also
chunks of HTML text, I should theoretically use :meth:`E.raw
<lino.utils.xmlgen.html.Namespace.raw>` to convert these to elements. Which
causes problems if they contain HTML entities.  Here is a snippet
which shows my problem:

>>> from xml.etree import ElementTree as ET
>>> s = """<p>&otilde;&auml;.</p>"""
>>> from lino.utils.xmlgen import etree
>>> ET.fromstring(s)
Traceback (most recent call last):
...
ParseError: undefined entity: line 1, column 3

The above was understandable: I must configure a parser who knows the
HTML entities:

>>> import htmlentitydefs
>>> p = ET.XMLParser()
>>> p.entity.update(htmlentitydefs.entitydefs)
>>> p.entity['otilde']
'\xf5'

And then invoke :func:`fromstring` with that parser:

>>> ET.fromstring(s, parser=p)

The problem is that even this gives the same error message.  Python
2.7.6.

After quite some fiddling I finally decided to give up and to generate
a plain string instead of using ElementTree.

Which raises the question: wouldn't it be even better to use Jinja and
a template for generating the summary?

Note that I also discovered `bleach
<http://bleach.readthedocs.org/en/latest/>`_ thanks to `this thread
<https://stackoverflow.com/questions/1765848/remove-a-tag-using-beautifulsoup-but-keep-its-contents>`_. I
didn't add `bleach` to the `install_requires` in
:xfile:`setup_info.py` because it is only used by
:mod:`lino.modlib.comments` and because it also works without bleach
(except that we don't remove the ``<p>`` tag then).  I remove the
``<p>`` tag because I suggest the convention to never write more than
one paragraph in the :attr:`short_text
<lino.modlib.comments.models.Comment.short_text>` field.

The public interface (:mod:`lino_noi.projects.bs3`) now also renders
comments.

I plan to upgrade Lino Noi on our bug database tomorrow morning so
that we will test the comments system on the field.