Parallel Computing

This page describes the "variables" that are associated with pages. Page variables have the form {$variable}, and can be used in page markup or in certain formatting strings in PmWiki. For example, the markup "{$Group}" renders in this page as "PmWiki".

Note: Do not confuse these variables (set and used only in PmWiki pages) with PHP variables. Page variables can be read in PHP with the PageVar() function.

Note that these variables do not necessarily exist in the PHP code, because they have to be determined for a specific page. (However, they are usable in FmtPageName strings.)

There is also the form {pagename$variable}, which returns the value of the variable for another page. For example, "{MarkupMasterIndex$Title}" displays as "Markup Master Index".

Default page variables

The page variables defined for PmWiki are:

In addition to the above, there are some page-invariant variables available through this markup:

Special references

Special referenced variables are used to specify the context of the variable when:

• the variable is included into a destination (target) page
• the variable is used in a sidebar, header, or footer.

Prefixing the variable name with an asterisk (*) means the variable's value is related to the browsed page or main (body) page.

• {*$PageVariablename} - prefixed by an asterisk (*) - value reflects the context of the browsed page.
  Without the asterisk the variable's value is provided by the page from which it originates, eg source page of include, sidebar, or header or footer.
  With asterisk the value will be provided by the browsed page, even if the markup comes from an included page or from a sidebar.
• {$PageVariablename} - retains value in source page context.
• {=$PageVariablename} - used only in pagelist templates to print the variable provided by each page from the pagelist.

For example you can test to see if the page is part of another page

(:if ! name {$FullName}:) 
%comment% name of this page is not the same as the page this text was sourced from
->[[{$FullName}#anchor | more ...]]
(:ifend:)

or refer to the main page in a sidebar, footer, or header

This page is [[{*$FullName}]]

Page variable security ($authpage)

The form {pagename$variable} in some PageLists, can display the values for other pages, regardless of the password protections.

If the other pages are protected and the visitor has no read permissions, PageVariables, unlike PageTextVariables, normally display the values. While most variables do not contain sensitive information, some of them could do: $Title, $Description and those starting with $LastModified.

Administrators and module developers can redefine the sensitive page variables to respect authentications, by using the "$authpage" variable instead of "$page" in the definition. The following snippet can be added in local/config.php -- it will rewrite the default possibly sensitive definitions to the secure ones.

foreach($FmtPV as $k=>$v) {
  if(preg_match('/^\\$(Title(spaced)?|LastModified(By|Host|Summary|Time)?|Description)$/', $k))
    $FmtPV[$k] = str_replace('$page', '$authpage', $v);
}

Custom page variables

You may add custom page variables as a local customization. In a local configuration file or a recipe script, use the variable $FmtPV:

$FmtPV['$VarName'] = "'variable definition'";
$FmtPV['$CurrentSkin'] = '$GLOBALS["Skin"]';

Defines new Page Variable of name $CurrentSkin, which can be used in the page with {$CurrentSkin} (also for Conditional markup). It's necessary to use the single quotes nested inside double-quotes as shown above (preferred) or a double-quoted string nested inside single-quotes like '"this"'.

You can make a string a Page Variable by adding the string to the $GLOBALS[] array first.

## Create a {$BaseUrl} page variable
$GLOBALS['BaseUrl'] = $UrlScheme."://".$_SERVER["HTTP_HOST"]."/Wiki";
$FmtPV['$BaseUrl'] = '$GLOBALS["BaseUrl"]';

You can also have a function create the string.

## Create a {$BaseUrl} page variable
function BaseUrl() { 
  global $UrlScheme;
  return $UrlScheme."://".$_SERVER['HTTP_HOST']."/Wiki"; 
}
$FmtPV['$BaseUrl'] = 'BaseUrl()';

See also

• Cookbook:More custom page variables
• PmWiki.Variables — about variables internal to PmWiki.
• PmWiki.MarkupMasterIndex — complete list of PmWiki markups.
• PageTextVariables — page variables automatically made available through natural page markup or explicit page markup within the wiki text of the page.
• PmWiki.Markup Expressions — markup expressions can process page variables.