20120519
========

User permissions
----------------

Until now I had noticed a few times but silently ignored 
the fact that the generated `lino*.js` contains a lot of 
useless class definitions for normal users. 
Only the root user needs them all.
Whether a user needs a table, 
depends on the user's level and on her group memberships.
The new permission system started a solution for this.
It was very flexible but 
would it make quite complex when becoming more granular. 

So here is the next step into this direction:
New attributes 
:attr:`required_user_groups <lino.core.actors.Actor.required_user_groups>`
and
:attr:`required_user_level <lino.core.actors.Actor.required_user_level>`.

Removed the `IntegTable` and `DebtsUserTable` classes which were
defined as abstract base classs for tables that are visible 
only to `debts`, `integ` users.
It is easier to simply define the above attributes in each table.

Removed :class:`lino.core.actions.ViewAction` which was used only
by :meth:`lino.ui.extjs3.ext_ui.ExtUI.build_site_cache`.
When generating the site cache, Lino now calls the 
new method :meth:`lino.core.actors.Actor.get_view_permission`.

Examples (to be completed and covered by unit tests):

- `lino.apps.pcsw.models.UsersWithClients` has two names in 
  :attr:`lino.core.actors.Actor.required_user_groups`::
  
    required_user_groups = ['integ','newcomers']
    
  That means: it exists only for members of 
  the `integ` **or** `newcomers` group. One membership is enough.
  A special User level is not required for this table. 
  Even a guest member of one of these groups would see it.

Cache sizes before and after::

  2 055 133 lino_root_de.js
  1 519 957 lino_caroline_de.js
  1 952 055 lino_melanie_de.js
  1 952 055 lino_hubert_de.js
  1 605 010 lino_kerstin_de.js

  2 055 140 lino_root_de.js
  1 404 827 lino_caroline_de.js
  1 853 767 lino_melanie_de.js
  1 741 197 lino_hubert_de.js
  1 402 816 lino_kerstin_de.js
  
  
Migration
---------

Added a little wrapper module :mod:`lino.apps.dsbe.migrate` 
needed when loading dumpy fixtures created before Lino 1.4.4.


Adapted :func:`lino.apps.pcsw.migrate.migrate_from_1_4_3` to the 
latest changes.

Especially the conversion of existing users is interesting.
See the source code for details.

Miscellaneous
-------------

While playing with the new version on the customer's site I 
noticed the need for a new configuration parameter:
:attr:`build_js_cache_on_startup <lino.Lino.build_js_cache_on_startup>`.

outbox.MyOutbox had no phantom record when called from the menu.
When called by permalink it had. 
This was because get_create_kw was called before 
Actor.setup_request() (which for outbox.MyOutbox sets the master_instance).