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Templates and output fields (API)

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[edit] Creating new template keywords

Elgg uses keywords within two sets of curly brackets in order to insert dynamic functionality into templates. For example, {{url}} displays the full URL of your site; {{sitename}} is your site's name, while {{username}} is the username of the currently logged in user and {{name}} is their full name.

Plugins can create new keywords in order to inject extra functionality into templates. Here's how:

[edit] Hooking into template variables

In the plugin_init() function, set the following variable: 

   (string) $CFG->templates->variables_substitute[your_keyword][]

This should be the name of a function that will return some HTML. Remember to set $CFG to global at the beginning of plugin_init()!

For example: 

   function plugin_init() {
        global $CFG;
       (string) $CFG->templates->variables_substitute[your_keyword][] = 'function';
    }

[edit] Writing your output function

Let's say you've set your function name to be plugin_your_keyword.

Template keywords can contain parameters, of the form {{keyword:param1:param2:...:paramn}}. These will be passed to your function, and therefore it needs to take one variable parameter, $vars. (Even if your keyword doesn't use parameters, your function will need to include this parameter.)

$vars is an array, where $vars[0] is the keyword itself and all elements $vars[1] through $vars[n] are the parameters.

The function needs to return HTML. A simple example is a function to return the current time when the keyword {{time}} is specified:

The plugin_init() portion: 

   function plugin_init() {
        global $CFG;
       $CFG->templates->variables_substitute['time'][] = (string) 'plugin_time';
    }

And the function itself: 

   function plugin_time($vars) {
   
       return (string) date("F j, Y, g:i a");
   
   }

If you wanted, you could amend this to provide a GMT time when {{time:gmt}} is specified: 

   function plugin_time($vars) {
       if (isset($vars[1]) && $vars[1] == "gmt") {
           return (string) gmdate("F j, Y, g:i a");
       } else {
           return (string) date("F j, Y, g:i a");
       }
   }

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