[drupal-devel] [feature] Enable multiple block regions (not just "left" and "right" sidebars)

Sun Apr 17 21:09:18 UTC 2005

Issue status update for http://drupal.org/node/16216

 Project:      Drupal
 Version:      cvs
 Component:    block.module
 Category:     feature requests
 Priority:     normal
 Assigned to:  Anonymous
 Reported by:  paragkenia
 Updated by:   nedjo
 Status:       patch

I agree with the suggested approach of themes registering their regions.
 I'd see this happening when a particular theme is activiated (or
upgraded).  Regions would be an array of names (e.g., 'left', 'right',
'footer').  New records would be created in the region table only for
region names not previously registered.

Some areas I'm not clear on, or that need further work:

Table naming
Should a new table be 'region' or 'regions' (I've used 'region')?  I
don't see a convention among existing table names, some of which are
singular and others plural.
Default values
I've kept the existing '0' and '1' ids for regions (left and right,
respectively), for backward compatibility.  But this means we can't use
autoincrement for the region id (rid), since autoincrements seem to
begin with 1.  Likely we should change to autogenerated ids.
Initial records
Using the INSERT INTO statements as I've done for the initial region
entries is probably counterproductive, since sooner or later they'll
have to be dynamically generated.  I was hoping this could be a
preliminary patch, with the main work coming later, but likely we need
to solve region registration by themes before this patch is applied.  I
don't have a good idea of how region registration by themes would be
implemented (a hook on theme activation?), and invite suggestions or
implementations.
Theme system changes
Besides region registration, the other change I'm seeing that would be
needed in the theme system is loading blocks by region name, rather
than region id.  This is because the ids currently used ('0' and '1')
in theory might be diffferent on a particular install.

nedjo

Previous comments:
------------------------------------------------------------------------

January 26, 2005 - 06:27 : paragkenia

I read the comparision discussion between *Drupal* and *Mambo*. In
several messages it was outlined that Drupal can place blocks only in
right and left and not flexible to put them on anywhere where one want.
It will be great if this can be changed in upcoming versions.

I am no pro at PHP, so don't know how much time this task will take,
but I think it is very important.

parag

------------------------------------------------------------------------

April 14, 2005 - 21:44 : nedjo

This issue was apparently partially addressed in issue
http://drupal.org/node/19694 [1].
[1] http://drupal.org/node/19694

------------------------------------------------------------------------

April 16, 2005 - 20:24 : nedjo

Attachment: http://drupal.org/files/issues/block-dynamic-regions.patch (8.17 KB)

This much-requested functionality - to have the ability to place blocks
in more than the two predefined regions - was partially addressed in
issue http://drupal.org/node/19694. [2].  But "blocks" are still
limited to the "left" and "right" sidebars (hard-coded in
block.module). 

This patch is a first step designed to enable multiple (eventually,
admin-definable) regions for blocks.  I've moved the existing "left"
and "right" block regions to a 'region' table (with ids of 0 and 1, as
currently used in themes).  Then all references to the regions are
drawn dynamically from the table.  This way, if further records are
added, they will appear in the list of available regions for block
placement.

Doing this actually reduces some duplicated code, since it's no longer
necessary to repeat code blocks for each of "left" and "right".

As it stands, the patch doesn't add any new functionality--but I don't
think it breaks anything either.  New functionality would need (a) new
regions defined, and (b) changes to themes.  A simple first step might
be, e.g., to add a "footer" region and then add a call in the footer
generation to append any blocks assigned to the footer region there.

I'm setting this to patch, but I'm aware that it needs some discussion
and refining before it'll be ready to apply.
[2] http://drupal.org/node/19694.

------------------------------------------------------------------------

April 16, 2005 - 21:05 : nedjo

Attachment: http://drupal.org/files/issues/block_regions.png (5.65 KB)

Here's a screenshot showing the  block admin page, with drop-downs for
region placement (the options are dynamically generated based on
defined regions).

------------------------------------------------------------------------

April 16, 2005 - 22:57 : adrian

The biggest problem with this is that you can have multiple themes, and
each of these themes can have different regions available.

Also, the method of defining which regions are available needs to be
standardised. Some of the work that me and Vlado are working on for the
install system would go towards solving that problem (ie: meta
information for modules, themes and styles).

This has been discussed to death, but the general consensus has been
that we _want_ to do this, but we need to solve a few other problems
properly first, the most pertinent being the interface issue. Chris
(factoryjoe) recently did a whole mess of workflows for something
related to this.

------------------------------------------------------------------------

April 17, 2005 - 00:09 : syscrusher

The first paragraph of adrian [3]'s post is a point that occurred to me
also, as I read this thread.

One suggestion would be to separate the definition and configuration of
blocks, on one hand, from the placement of those blocks, on the other
hand.

In other words, Drupal core provides a mechanism defining what blocks
exist, which of these are on by default or off by default and
user-selectable vs. which are forced on for all users, and the
configuration (if applicable) of specialized blocks defined by
particular modules.

Each theme provides a standard hook function that returns an array of
region names and help/description text, e.g., array('left'=>t('This
vertical region is left of the main content area'), 'right'=>t('This
vertical region is right of the main content area'), 'footer'=>t('The
footer is below the left, right, and main content areas of the page')).

The theme part of Drupal core (i.e., theme.module itself, not the
individual themes) provides a standard UI that is displayed within
config of *each theme* (but is one physical code base within
theme.module) that allows the administrator to map blocks defined by
Drupal core into regions defined by the theme, and storing that mapping
as an theme-to-block_ID-to-region_ID (with weight) table in the
database. From there, the actual page rendering is similar to what's
being done now, but there is more of it.

I guess what I'm trying to say is that the key to solving this problem
is breaking it along its degrees of orthogonality, and there are three
-- two in Drupal core and one in the individual theme.

Scott
[3] http://drupal.org//user/1517

------------------------------------------------------------------------

April 17, 2005 - 03:14 : Dries

Scott, is right.  The theme should export its available regions.  Then
the administrator's task is to assign blocks to regions (not to setup
regions).  A theme could have configurable regions, but that internal
to the theme.

To me, the real challenge is the UI and the interaction design. 
Configuring blocks could easily become a real pain (while most themes
continue to use 'left' and 'right'.) 

Of course, we can implement all the functionality, default everything
to 'left' and 'right', and worry about the UI later. This should be
fairly straightforward to implement and nedjo's patch looks like a
first step in the right direction.