1: <?php
  2: /**
  3:  * Publish-Subscribe system based on Phly_PubSub
  4:  * (http://weierophinney.net/matthew/archives/199-A-Simple-PHP-Publish-Subscribe-System.html)
  5:  *
  6:  * Copyright 2008-2011 Matthew Weier O'Phinney
  7:  * Copyright 2011-2012 Horde LLC (http://www.horde.org/)
  8:  *
  9:  * @category  Horde
 10:  * @package   PubSub
 11:  * @author    Matthew Weier O'Phinney <mweierophinney@gmail.com>
 12:  * @license   New BSD {@link http://www.opensource.org/licenses/bsd-license.php}
 13:  */
 14: 
 15: /**
 16:  * Publish-Subscribe system
 17:  *
 18:  * @category  Horde
 19:  * @package   PubSub
 20:  */
 21: class Horde_PubSub
 22: {
 23:     /**
 24:      * Subscribed topics and their handles
 25:      */
 26:     protected static $_topics = array();
 27: 
 28:     /**
 29:      * Publish to all handlers for a given topic
 30:      *
 31:      * @param  string $topic
 32:      * @param  mixed $args All arguments besides the topic are passed as arguments to the handler
 33:      * @return void
 34:      */
 35:     public static function publish($topic, $args = null)
 36:     {
 37:         if (empty(self::$_topics[$topic])) {
 38:             return;
 39:         }
 40:         $args = func_get_args();
 41:         array_shift($args);
 42:         foreach (self::$_topics[$topic] as $handle) {
 43:             $handle->call($args);
 44:         }
 45:     }
 46: 
 47:     /**
 48:      * Subscribe to a topic
 49:      *
 50:      * @param  string $topic
 51:      * @param  string|object $context Function name, class name, or object instance
 52:      * @param  null|string $handler If $context is a class or object, the name of the method to call
 53:      * @return Horde_PubSub_Handle Pub-Sub handle (to allow later unsubscribe)
 54:      */
 55:     public static function subscribe($topic, $context, $handler = null)
 56:     {
 57:         if (empty(self::$_topics[$topic])) {
 58:             self::$_topics[$topic] = array();
 59:         }
 60:         $handle = new Horde_PubSub_Handle($topic, $context, $handler);
 61:         if (in_array($handle, self::$_topics[$topic])) {
 62:             $index = array_search($handle, self::$_topics[$topic]);
 63:             return self::$_topics[$topic][$index];
 64:         }
 65:         self::$_topics[$topic][] = $handle;
 66:         return $handle;
 67:     }
 68: 
 69:     /**
 70:      * Unsubscribe a handler from a topic
 71:      *
 72:      * @param  Horde_PubSub_Handle $handle
 73:      * @return bool Returns true if topic and handle found, and unsubscribed; returns false if either topic or handle not found
 74:      */
 75:     public static function unsubscribe(Horde_PubSub_Handle $handle)
 76:     {
 77:         $topic = $handle->getTopic();
 78:         if (empty(self::$_topics[$topic])) {
 79:             return false;
 80:         }
 81:         if (false === ($index = array_search($handle, self::$_topics[$topic]))) {
 82:             return false;
 83:         }
 84:         unset(self::$_topics[$topic][$index]);
 85:         return true;
 86:     }
 87: 
 88:     /**
 89:      * Retrieve all registered topics
 90:      *
 91:      * @return array
 92:      */
 93:     public static function getTopics()
 94:     {
 95:         return array_keys(self::$_topics);
 96:     }
 97: 
 98:     /**
 99:      * Retrieve all handlers for a given topic
100:      *
101:      * @param  string $topic
102:      * @return array Array of Horde_PubSub_Handle objects
103:      */
104:     public static function getSubscribedHandles($topic)
105:     {
106:         if (empty(self::$_topics[$topic])) {
107:             return array();
108:         }
109:         return self::$_topics[$topic];
110:     }
111: 
112:     /**
113:      * Clear all handlers for a given topic
114:      *
115:      * @param  string $topic
116:      * @return void
117:      */
118:     public static function clearHandles($topic)
119:     {
120:         if (!empty(self::$_topics[$topic])) {
121:             unset(self::$_topics[$topic]);
122:         }
123:     }
124: }
125: