Additional sidebars for Serendipity templates

Serendipity provides 3 default sidebars - left, hidden and right. The hidden sidebar is used for positioning plugins that you do not necessarily want to delete, but also do not want to display on the front end.



Many templates are available with additional sidebars. A recent release by Carl Galloway is his port of Dream City. Dream City defines additional sidebars of "top" and "middle". From "configure plugins", the template user can then assign sidebar items to any of these sidebar positions:



This additional sidebar definition occurs in a template's config.inc.php file. In Dream City, the code is this:

$template_config = array(
array(
'var' => 'sidebars',
'name' => SIDEBAR_TITLE,
'type' => 'string',
'default' => 'left,hide,right,top,middle,'
)

A template user also sees this definition in "manage styles" anytime the template's configuration is modified:



There is a potential danger lurking there, and while not obvious in this screenshot, it is from a screenshot taken from a different template (note the ominous warning: "please DON'T edit this field"):



So, what is the danger? The reason for this is seen in a template's use of the very specific sidebar names. In the Dream City template's index.tpl file, the "top" sidebar is emitted using the following code, which will not work if the sidebar name is changed from "top" to anything else:

{serendipity_printSidebar side="top"}

Fortunately, this one is easy to fix. Simply change the sidebar from 'type' => 'string' to 'type' => 'hidden'. Your custom sidebars still exist, but can no longer be viewed or edited from "manage styles". If an admin really wanted to modify them, just edit the template's config.inc.php file. Thanks to Judebert for that tip a very long time ago!

EDIT 11 Nov 08:One critical piece of information I failed to mention when this entry was first written: In addition to changing the type from 'string' to 'hidden', you must also change 'default' to 'value'. So, using the above example, the modification would look like this:

$template_config = array(
array(
'var' => 'sidebars',
'name' => SIDEBAR_TITLE,
'type' => 'hidden',
'value' => 'left,hide,right,top,middle,'
)

Conditional code for sidebar processing.
Many templates that use custom sidebars process the sidebar code regardless of whether or not any sidebar items exist for that specific sidebar column. But what if you wanted to save some of grandma's performance pennies, or perhaps didn't want to emit a certain html container if, for instance, your "top" sidebar had no items? Smarty to the rescue!

Serendipity already gives us Smarty variables for our left and right sidebars, which respectively, are $leftSidebarElements and $rightSidebarElements. So if we wanted to conditionally process a block of code only if there truly are left side bar items, we could so something like this in our smarty tpl file:

{if $leftSidebarElements > 0}
<div id="serendipityLeftSideBar">
{serendipity_printSidebar side="left"}
<div>
{/if}

We can create our own smarty variables to do exactly the same thing for our custom sidebars as well. Using the above example of a "top" sidebar, this is what we need to add in our config.inc.php file, which I tend to place at the very end of the file:

$topSidebarElements = serendipity_plugin_api::count_plugins('top');
$serendipity['smarty']->assign_by_ref('topSidebarElements', $topSidebarElements);

So, just like $leftSidebarElements and $rightSidebarElements, we now have $topSidebarElements, and can emit code only if sidebar items have actually been assigned to that custom sidebar. Thanks to Abdussamad for turning me onto that concept a long time ago!

So there you have it! Any number of sidebars for your template. It is worth noting that screen width does disappear quickly with a bunch of sidebars. Horizontal scrolling is usually something to be avoided, so only add additional sidebars where you truly need them, and not just because "you can".

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