One of the purposes of Wiki Groups is to allow a Wiki Administrator to customize the features of PmWiki on a per-group basis. Here is where per group customizations come into play.

To perform local customizations for a particular WikiGroup,

• place the customizations in a file called "<groupname>.php" (where <groupname> is the actual name of the page group in question) in the local/ subdirectory
• place the css customizations in a file called "<groupname>.css" (where <groupname> is the actual name of the page group in question) in the css/ subdirectory.

These files will be automatically processed after processing any local customizations in the config.php and local.css files.

For example, to change the image displayed in the upper-left corner of pages in the "GroupName" WikiGroup, one could create local/GroupName.php containing

<?php
$PageLogoUrl = "/myimages/chess.gif";  The example's effect would cause all pages in the GroupName Wiki Group to use "/myimages/chess.gif" as the logo image instead of the default. To add markup to the beginning or end of each page in a wiki group, see Group headers. ### Per-page customizations PmWiki also allows per-page customizations, simply use the full name of the page to be customized instead of the group. For example, one can use the file local/Chess.HomePage.php to set local customizations for Chess.HomePage. Almost any customization that would be placed in config.php can be used as a per-group or per-page customization. An important exception to this is setting per-group or per-page customizations for recipe scripts included in config.php. Most recipe scripts would need any customization variables defined before the script is included. Instead of using a per-group or per-page customization php file, use a per-group or per-page conditional statement in config.php, before including the recipe script. Example: $page = PageVar($pagename, '$FullName');
$group = PageVar($pagename, '$Group'); //per-group customizations: if($group=='GroupName') {
$RecipeVariable = 'valueA'; etc. ... } //per-page customizations: if($page=='GroupName.PageName) {

### Authentication

Any passwords required for a group should be set in the group's Group Attributes? page (see Passwords Administration) and not in a group customization file.

### Consider Wiki Farms

Wiki Groups are an easy way to host multiple sites in a single PmWiki installation by giving each site its own group. Another approach is to use Wiki Farms, which allows each site to have its own set of Wiki Group and local customization files. Read about

If you are looking for nested group levels, you may want to consider Pm's design considerations on hierarchical groups.

How can I apply CSS styles to a particular group or page?

Simply create a pub/css/Group.css or pub/css/Group.Page.css file containing the custom CSS styles for that group or page.

Why shouldn't passwords be set in group (or page) customization files?

The reason for this advice is that per-group customization files are only loaded for the current page. So, if $DefaultPasswords['read'] is set in local/GroupA.php, then someone could use a page in another group to view the contents of pages in GroupA. For example, Main.WikiSandbox could contain: (:include GroupA.SomePage:) and because the GroupA.php file wasn't loaded (we're looking at Main.WikiSandbox --> local/Main.php), there's no read password set. The same is true for page customization files. Isn't that processing order strange? Why not load per page configuration last (that is after global configuration an per group configuration)? Many times what we want to do is to enable a certain capability for a group of pages, but disable it on a specific page, as if it was never enabled. If the per-group config file is processed first, then it becomes very difficult/tedious for the per-page one to "undo" the effects of the per-group page. So, we load the per-page file before the per-group. If a per-page customization wants the per-group customizations to be performed first, it can use the techniques given in PmWiki.PerGroupCustomizations (using include_once() or setting $EnablePGCust = 0).