:date: 2017-02-25

===========================
Saturday, February 25, 2017
===========================

Bleach and html5lib
===================

Good news for :ticket:`1262` : Will Kahn-Greene (author of bleach) has
fixed `issue229
<https://github.com/mozilla/bleach/issues/229#issuecomment-282367178>`__. He
asked me to test whether it works now. Here we go::

    $ pip uninstall -y weasyprint html5lib bleach
    $ pip install https://github.com/mozilla/bleach/archive/543984c.tar.gz#egg=bleach
    $ pip install weasyprint html5lib

Yes, the import itself now works::
  
    $ python -c "import bleach"

That is, the incompatability is fixed. We can close :ticket:`1262`.

I modified :mod:`lino.mixins.bleached` (which was deactivated until
now) so that now the module should be active. I also extended the
docstring. I activated it for
:mod:`lino.modlib.comments.models.Comment`.  That is, every comment is
going to be bleached.

Now we should test whether this is actually what we want. New ticket
:ticket:`1522`.

For example it is possible that I forgot to specify in
:attr:`allowed_tags <lino.mixins.bleached.Bleacher.allowed_tags>` some
tags that we do *not* want to remove.

I think the best test is to use it on the battle field.

One challenge here is that the usage is currently "destructive": when
we deploy it to our production site, all comments will automatically
get bleached with our data migration. And we won't even get a
notification of which rows are concerned. We need at least a kind of
"bleach logger".

A first idea is to override :meth:`after_ui_save` instead of
:meth:`full_clean`. This makes everything less destructive.
(I forgot to check this in, so it is visible only in 20170226)

TODO: Lino should log at least a bit of bleach's "activity". I mean
for example that :meth:`Bleached.before_ui_save
<lino.mixins.bleached.Bleached.before_ui_save>` should log an info
message saying "removed tags x, y, z from short_text"

Almost all test suites seem to be passing now when Lino branch
``Comment.reply_to_common_work`` is activated. An exeception is still
:ref:`presto` which says :message:`Exception: TicketDetail on
tickets.Tickets has no data element 'changes.ChangesByMaster'`. It is
technically trivial, but conceptually complex: we need to decide
whether :ref:`presto` wants :mod:`lino.modlib.changes` or not...