Saturday, February 6, 2016

Advancing with Lino Voga

Continuous courses are a new concept in Lino Voga. It is another way of managing enrolments to a course. While a classical course has a fixed and previously known series of calendar events, a continuous course is running all the time. Participants pay a fee which gives them permission to assist in a number of events, and then they come and go.

I removed the rule that the enrolments_until of a course is set to its start_date. Because there are continuous courses

The Roger variant of Lino Voga has referrable courses. Last year they introduced a “reference number” for every single course. TODO: what will happen next year with these numbers? I suggest to change the ref of the 2016 courses with “2016” so that the known references can be reused for the corresponding 2017 course.

TODO: where should the new Course.ref appear?

The lino.modlib.about.models.About window now shows the languages of that site.

ValueError: dictionary update sequence element #0 has length NN; 2 is required

This comes because wkhtmltopdf needs a manual patch in site-packages/wkhtmltopdf/utils.py:

def render_to_temporary_file(template, context, mode='w+b', bufsize=-1,
                                 suffix='.html', prefix='tmp', dir=None,
                                 delete=True):
    # deactivated by Luc Saffre 20160206
    # make sure the context is a context object
    # if not isinstance(context, (Context, RequestContext)):
    #     context = Context(context)

    content = smart_text(template.render(context))
    content = make_absolute_paths(content)

And then I still had the following error:

CalledProcessError: Command ‘[‘wkhtmltopdf’, ‘–encoding’, u’utf8’, ‘–quiet’, ‘/tmp/wkhtmltopdfQW_4es.html’, ‘-‘]’ returned non-zero exit status -6

This was because the wkhtmltopdf system package (not python) is 0.12.1 instead of 0.9.9.

It’s a known bug. Here is how to demonstrate it:

$ wkhtmltopdf --encoding utf8 --quiet test.html -
QXcbConnection: Could not connect to display
Aborted

Solution was to

  • install xvfb (sudo apt-get install xvfb

  • and to add to my settings.py file:

    WKHTMLTOPDF_CMD = 'xvfb-run wkhtmltopdf'

Lino goes Wikipedia

Oh cool, Hamza started a Wikipedia article about Lino:

Contributions and ideas are welcome! I’ll try to stay in background…