Hook for future geocoding library added.

git-svn-id: https://code.elgg.org/elgg/trunk@2488 36083f99-b078-4883-b0ff-0f9b5a30f544

1 files changed, 94 insertions, 0 deletions

diff --git a/engine/lib/location.php b/engine/lib/location.php
new file mode 100644
index 000000000..eec665234
--- /dev/null
+++ b/engine/lib/location.php
@@ -0,0 +1,94 @@
+<?php
+
+	/**
+	 * Elgg geo-location tagging library.
+	 * 
+	 * @package Elgg
+	 * @subpackage Core
+	 * @license http://www.gnu.org/licenses/old-licenses/gpl-2.0.html GNU Public License version 2
+	 * @author Curverider Ltd
+	 * @copyright Curverider Ltd 2008
+	 * @link http://elgg.org/
+	 */
+
+	/**
+	 * Define an interface for geo-tagging entities.
+	 *
+	 */
+	interface Locatable
+	{
+		/** Set a location text */
+		public function setLocation($location);
+		
+		/**
+		 * Set latitude and longitude tags for a given entity.
+		 *
+		 * @param float $lat
+		 * @param float $long
+		 */
+		public function setLatLong($lat, $long);
+		
+		/**
+		 * Get the contents of the ->geo:lat field.
+		 *
+		 */
+		public function getLatitude();
+		
+		/**
+		 * Get the contents of the ->geo:lat field.
+		 *
+		 */
+		public function getLongitude();
+		
+		/**
+		 * Get the ->location metadata. 
+		 *
+		 */
+		public function getLocation();
+	}
+
+	/**
+	 * Encode a location into a latitude and longitude, caching the result.
+	 *
+	 * Works by triggering the 'geocode' 'location' plugin hook, and requires a geocoding module to be installed
+	 * activated in order to work.
+	 * 
+	 * @param String $location The location, e.g. "London", or "24 Foobar Street, Gotham City"
+	 */
+	function elgg_geocode_location($location)
+	{
+		global $CONFIG;
+		
+		$location = sanitise_string($location);
+		
+		// Look for cached version
+		$cached_location = get_data_row("SELECT * from {$CONFIG->dbprefix}geocode_cache WHERE location='$location'");
+		
+		// Trigger geocode event
+		$return = false;
+		$return = trigger_plugin_hook('geocode', 'location', array('location' => $location, $return));
+		
+		// If returned, cache and return value
+		if (($return) && (is_array($return)))
+		{
+			$lat = (int)$return['lat'];
+			$long = (int)$return['long'];
+			
+			// Put into cache at the end of the page since we don't really care that much
+			execute_delayed_write_query("INSERT DELAYED INTO {$CONFIG->dbprefix}geocode_cache (lat, long) VALUES ({$lat}, {$long}) ON DUPLICATE KEY UPDATE lat={$lat} long={$long}");
+		}
+		
+		return $return;
+	}
+	
+	// Some distances in degrees (approximate)
+	define("MILE", 0.01515);
+	define("KILOMETER", 0.00932);
+	
+	
+	// TODO: get objects within x miles by entities, metadata and relationship
+	
+	// TODO: List 
+	
+	
+?>
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