PmWiki is a wiki-based system for collaborative creation and maintenance of websites.

PmWiki pages look and act like normal web pages, except they have an "Edit" link that makes it easy to modify existing pages and add new pages into the website, using basic editing rules. You do not need to know or use any HTML or CSS. Page editing can be left open to the public or restricted to small groups of authors.

Key PmWiki Features

PmWiki is written in PHP and distributed under the General Public License. It is designed to be simple to install, customize, and maintain for a variety of applications. This site is running pmwiki-2.2.11.

PmWiki is a registered trademark of Patrick R. Michaud.

PmWiki's home on the web is at pmwiki.org. This page describes the skin template files (.tmpl) that are used to create PmWiki skins, and how PmWiki uses them. As described in the skins page, a skin is a collection of files that specifies the layout for PmWiki pages. Each skin must include a template file that provides the skeleton for displaying a PmWiki page.

Finding and Processing Templates

When you set the value of the $Skin variable in a configuration file like local/config.php, like this

## Use the Foo Skin.
$Skin = 'foo';

it tells PmWiki to search for a skin of that name, and use it. The usual result of the search is for PmWiki to load a template file from the appropriate skin directory. In this example, that would probably be the file pub/skins/foo/foo.tmpl.

The actual processing that PmWiki goes through to find a template file is important for those who are making complex skins, so its worth mentioning what those steps are:

1. When $PageTemplateFmt is blank (as it should be), PmWiki gathers the names of all candidate skins. It starts with any action-specific skin that is specified in $ActionSkin[$action]. Thus, if the current action is 'login', and $ActionSkin['login'] is 'Bar', then PmWiki will look for a skin named 'Bar'.
2. If no skin has been found yet, it looks for the skin(s) named in the $Skin variable (which is allowed to be an array) and uses the first skin it can find. If it gets to the end of the list without finding a skin, it issues an error.
3. To attempt to find a skin, PmWiki first consults the $SkinLibDirs variable to know where to look. Skins consist of server-side files that are loaded by PmWiki (such as .php and .tmpl files) and client-side files (such as .css files and images) that will be requested by the user's browser when they look at a skinned PmWiki page. $SkinLibDirs is an array of key/value pairs. The key is a directory to look in for the server-side files, while the corresponding value is a URL that points to the public client-side resources used by the skin. The default value of $SkinLibDirs is:

   $SkinLibDirs = array(
      "./pub/skins/\$Skin"      => "$PubDirUrl/skins/\$Skin",
      "$FarmD/pub/skins/\$Skin" => "$FarmPubDirUrl/skins/\$Skin");
   

   So, using the above definitions, PmWiki would try to find the skin 'foo' by looking for a directory called ./pub/skins/foo and then for $FarmD/pub/skins/foo (with the value of $FarmD replaced by the root server directory for Farm files). The first such directory that was found would be assumed to contain the skin it was looking for. It would then set $SkinDir to the name of this directory and $SkinDirUrl to the corresponding URL.
4. Once a valid skin directory has been found, PmWiki starts processing the files in that directory, looking for a .php skin file to run. It first looks for one with the same name as the skin. So, if the skin is 'foo', it looks for foo.php. If no such file is found, it then checks for a file named skin.php. If one of these .php files is found, PmWiki loads and runs it. This allows a skin to define custom markup, or custom configuration parameters. It also allows a skin to choose between which of several different .tmpl files to load.
   To specify which .tmpl file to load, simply call LoadPageTemplate() inside the skin .php file, with the name of the .tmpl file to be loaded:
   LoadPageTemplate($pagename, "$SkinDir/xyz.tmpl");
   For example, a skin might specify a special template to be used if the action is 'print':

   if ($GLOBALS['action'] == 'print')
     LoadPageTemplate($pagename, "$SkinDir/print.tmpl");
   

   When the action is something else, PmWiki will fall back to loading the default .tmpl file instead.
5. If no appropriate .php file is found, or if that file doesn't load a template, then PmWiki falls back to looking for a template with the same name as the skin, or, failing that, any .tmpl file at all, so long as its the only one in the directory. If it finds one, it will load and process it. If not, it will issue an error.

Template file format

A template file is basically an HTML file that also contains variable substitutions (indicated by '$') and special directives embedded in HTML comments. The following special directives are required in the template file.

1. The directive <!--PageText--> belongs to the <body> section of the HTML document, and tells PmWiki where the main content of each wiki page should be placed.
2. The directive <!--HTMLHeader-->, which goes somewhere in the <head> section of the HTML document.
3. The directive <!--HTMLFooter--> directive, which typically goes before the final </body> tag and is used by some recipes to insert things at the end of the HTML document. Prior to PmWiki 2.2.0 the <!--HTMLFooter--> directive was optional.

When PmWiki displays a page, it replaces the directives and variable substitutions with the values appropriate to the current page. For example, the <!--PageText--> directive is replaced with the page's contents, while any instances of $PageUrl are replaced with the url (address) of the current page.

There is a long list of variables available for substitution in pages; some of the most useful include:

$PageUrl         the url of the current page
$ScriptUrl       the base url to the pmwiki.php script
$Title           the page's title (e.g., "`SkinTemplates")
$Titlespaced     the page's title with spaces (e.g., "Skin Templates")
$Group           the name of the current group  (e.g., "`PmWiki")
$FullName        the page's full name (e.g., "`PmWiki.SkinTemplates")
$LastModified    the page's last modification time
$PageLogoUrl     the url of a site logo
$WikiTitle       the site's title
$SkinDirUrl      the url of the skin's folder

This last variable, $SkinDirUrl, is particularly useful in templates as it allows the skin designer to refer to other files (such as images or style sheets) in the skin folder without having to know the exact url.

The template is not limited to using the variables listed here; nearly any PHP global variable that begins with a capital letter can be used in a skin template. Page variables can also be used in templates.

Skin directives

Besides the required <!--PageText--> and <!--HTMLHeader--> directives, PmWiki provides other built-in directives for generating page output. It's not necessary to use any of these directives, but they can often add capabilities to a skin

<!--wiki:Main.SomePage-->

<!--page:Main.SomePage-->

The <!--wiki:Main.SomePage--> directive outputs the contents of Main.SomePage. $-substitutions are allowed in directives, thus a directive like <!--wiki:$Group.SomePage--> will include "SomePage" of the current group.

If multiple pages are listed in the directive, then only the first available page is used. Thus <!--wiki:$Group.SomePage Site.SomePage--> will display the contents of SomePage in the current group if it exists, and Site.SomePage if it doesn't. To always display Site.SomePage, even if $Group.SomePage exists, use two consecutive <!--wiki:...--> directives.

The <!--wiki:...--> directive only displays pages for which the browser has read permissions. The <!--page:...--> directive displays pages even if the browser doesn't have read permission.

<!--file:somefile.txt-->

The directive <!--file:somefile.txt--> outputs the contents of another file (on the local filesystem) at the point of the directive. If the file to be included is a .php script, then the PHP script is executed and its output is sent to the browser. Like the <!--wiki:...--> directive above, $-substitutions are available to be able to output files based on the current page name or group.

<!--markup:...-->

The markup directive processes any text that follows the colon as wiki markup and displays that in the output.

<!--function:SomeFunction args-->

This directive calls a PHP function named "SomeFunction", passing the current page's name and the text following the function name as arguments. PHP functions called in this manner are typically defined in a local customization file. Args allows only one argument, which has to be splitted then. <!--function:SomeFunction arg1 arg2 arg3--> generates one parameter "arg1 arg2 arg3". However variables can be used (like $LastModifiedBy).

Page sections

A template file can designate "sections" that are included or excluded from the output based on page directives or other criteria. A section always begins with <!--Page...Fmt--> and continues to the next section, the end of the template file, or <!--/Page...Fmt-->. For example, a template can specify a <!--PageLeftFmt--> section that is excluded from the output whenever the (:noleft:) directive is encountered in the page's contents. PmWiki's predefined sections (and their corresponding page directives) are:

<!--PageHeaderFmt-->          (:noheader:)
<!--PageFooterFmt-->          (:nofooter:)
<!--PageTitleFmt-->           (:notitle:)
<!--PageLeftFmt-->            (:noleft:)
<!--PageRightFmt-->           (:noright:)
<!--PageActionFmt-->          (:noaction:)

Skin designers can define custom sections and markups, but currently all section names in the template must begin with "Page" and end with "Fmt". As mentioned you also have to define the corresponding markup (for example in your config.php) like this:

Markup('noxyz', 'directives',  '/\\(:noxyz:\\)/ei',
    "SetTmplDisplay('PageXYZFmt',0)");

Internationalization (i18n)

Skins can also be internationalized by using $[...] substitutions. Any string placed inside of $[...] is treated as a "translatable phrase", and the phrase is looked up in the current translation tables for a corresponding output phrase. If a translation is available, then the translated phrase is substituted at that point, otherwise the original phrase is left intact.

For example, the substitution $[Edit] will display the current translation of "Edit" if it is known, otherwise it displays "Edit". Thus, the same template can be used for multiple languages, displaying "Editer" when French translations are loaded, "Bearbeiten" when German translations are loaded, and "Edit" when no translation is available.

Understanding old config files

The original method of telling PmWiki where to find a skin used to be to set $PageTempateFmt to the path of a .tmpl file on the server. This is still respected by PmWiki, so if, for example, you were to set $PageTemplateFmt to ./pub/skins/foo/foo.tmpl then PmWiki would simply load and use that file, but without setting the special $SkinDir and $SkinDirUrl variables that are required by all modern skins.