# Wednesday, October 18, 2017¶

## Models for newbies documentation¶

After stumbling over Tim Kholod’s nice blogpost The simple way to understand Django models, I started to write Introduction to models (which mentions it).

## Common accounts¶

I added two virtual fields to lino_xl.lib.accounts.CommonAcccounts, and added the table to the Explorer menu.

## Connect using a Belgian eID card¶

It seems that for Belgium it’s only a few lines of code.

There is also a backend for Google OpenId, OAuth2, OAuth1, Google+. That might be interesting for Hamza who is working on #2013.

## FieldDoesNotExist: Event has no field named ‘_event_type_cache’¶

Yesterday with Johanna we had an error which happens from time to time:

File "/xl/lino_xl/lib/cal/models.py", line 560, in after_ui_save
super(Event, self).after_ui_save(ar, cw)
File "/lino/lino/modlib/notify/mixins.py", line 144, in after_ui_save
ar, self, mt, msg, self.get_change_observers())
File "/lino/lino/modlib/notify/models.py", line 213, in emit_message
subject_body = msg_func(user, mm)
File "/lino/lino/modlib/notify/mixins.py", line 135, in msg
return (subject, self.get_change_body(ar, cw))
File "/lino/lino/modlib/notify/mixins.py", line 67, in get_change_body
File "/lino/lino/core/diff.py", line 68, in get_updates_html
f = self.watched._meta.get_field(k)
File "/site-packages/django/db/models/options.py", line 619, in get_field
raise FieldDoesNotExist("%s has no field named '%s'" % (self.object_name, field_name))
FieldDoesNotExist: Event has no field named '_event_type_cache'


It seems that the __dict__ of a Django database object can now contain additional names used internally by Django.

I didn’t write an automatic way to reproduce it, but I now fixed it at least theoretically, and at least the test suite passes.

Side effect: The lino.core.diff.ChangeWatcher.get_updates() method now sorts its result in order to make it predictable for test cases.

En passant I fixed another bug AjaxExceptionResponse KeyError: u'obj' in request POST /api/tickets/Tickets which occured when sending an update notification to a user in German. Because the text “{user} created {what}” had been translated to “{user} hat {obj} erstellt” ({obj} instead {what}).

For #2119 I added a new notification mode silent.

This mode differs from never: “never” means that you want to get notified, but only in the web interface, not via E-Mail. The new option “silent” means that notifications are completely disabled and not even being created.

To be observed. I am not sure whether they really want this.

## Cannot query “1Euro-Shop”: Must be “Person” instance¶

Lydia had an error message “ValueError: Cannot query “1Euro-Shop”: Must be “Person” instance”. In the virtual fields suppliers and needed_skills we had to add:

if not isinstance(self, dd.plugins.faculties.demander_model):
return ''