doc/dev/refactoring-the-css-with-uiprops.rst
author Alexandre Richardson <alexandre.richardson@logilab.fr>
Tue, 12 Jan 2016 14:31:14 +0100
changeset 11169 c1eb5a676c80
parent 10492 68c13e0c0fc5
permissions -rw-r--r--
[rset] Always complete attribute/relation caches in ResultSet.get_entity RQL queries are often designed to fill up the ORM's caches when fetching entities out of the result set. Until now, if an entry already existed in the entity cache, ResultSet.get_entity would return it unchanged, not using the new ResultSet's contents to update the attribute cache, breaking expectations (if the attributes are needed, they'd then be fetched later one at a time, one entity at a time), resulting in loads of DB accesses. So we change ResultSet.get_entity so that: * if the entity is already cached and has been instantiated from the same rset, it is returned as-is (to avoid loops) * if the entity is not yet cached, it is instantiated * if the entity is cached via another rset, its attribute/relation caches are completed Closes #9942503

=========================================
Refactoring the CSSs with UI properties
=========================================

Overview
=========

Managing styles progressively became difficult in CubicWeb. The
introduction of uiprops is an attempt to fix this problem.

The goal is to make it possible to use variables in our CSSs.

These variables are defined or computed in the uiprops.py python file
and inserted in the CSS using the Python string interpolation syntax.

A quick example, put in ``uiprops.py``::

  defaultBgColor = '#eee'

and in your css::

  body { background-color: %(defaultBgColor)s; }


The good practices are:

- define a variable in uiprops to avoid repetitions in the CSS
  (colors, borders, fonts, etc.)

- define a variable in uiprops when you need to compute values
  (compute a color palette, etc.)

The algorithm implemented in CubicWeb is the following:

- read uiprops file while walk up the chain of cube dependencies: if
  cube myblog depends on cube comment, the variables defined in myblog
  will have precedence over the ones in comment

- replace the %(varname)s in all the CSSs of all the cubes

Keep in mind that the browser will then interpret the CSSs and apply
the standard cascading mechanism.