Marcus Povey <marcus@dushka.co.uk>

* Export functionality for ElggEntity and children

git-svn-id: https://code.elgg.org/elgg/trunk@287 36083f99-b078-4883-b0ff-0f9b5a30f544

2 files changed, 154 insertions, 5 deletions

diff --git a/engine/lib/entities.php b/engine/lib/entities.php
index 5dee5a4bb..8044b1df9 100644
--- a/engine/lib/entities.php
+++ b/engine/lib/entities.php
@@ -295,7 +295,19 @@
 		{ 
 			return delete_entity($this->get('guid'));
 		}
-		
+
+		/**
+		 * Export this class into a stdClass containing all necessary fields.
+		 * Override if you wish to return more information than can be found in $this->attributes (shouldn't happen) 
+		 * 
+		 * @return stdClass
+		 */
+		public function export() 
+		{ 
+			$tmp = new stdClass; 
+			$tmp->attributes = $this->attributes; 
+			return $tmp; 
+		}
 	}
 
 	/**
@@ -677,4 +689,30 @@
 		return delete_data("DELETE from {$CONFIG->dbprefix}entity_relationships where guid_one=$guid_one and relationship='$relationship' and guid_two=$guid_two");
 	}
 
+	/**
+	 * Handler called by trigger_plugin_hook on the "export" event.
+	 */
+	function export_entity_plugin_hook($hook, $entity_type, $returnvalue, $params)
+	{
+		// Sanity check values
+		if ((!is_array($params)) && (!isset($params['guid'])))
+			throw new InvalidParameterException("GUID has not been specified during export, this should never happen.");
+			
+		if (!is_array($returnvalue))
+			throw new InvalidParameterException("Entity serialisation function passed a non-array returnvalue parameter");
+			
+		$guid = (int)$params['guid'];
+		
+		// Get the entity
+		$entity = get_entity($guid);
+		
+		if ($entity instanceof ElggEntity)
+			$returnvalue[] = $entity; // Add object to list of things to serialise - actual serialisation done later
+
+		return $returnvalue;
+	}
+	
+	/** Register the hook, ensuring entities are serialised first */
+	register_plugin_hook("export", "all", "export_entity_plugin_hook", 0);
+	
 ?>
\ No newline at end of file
diff --git a/engine/lib/export.php b/engine/lib/export.php
index 4a39d295f..89b5a1ef5 100644
--- a/engine/lib/export.php
+++ b/engine/lib/export.php
@@ -15,14 +15,45 @@
 	 * 
 	 * This function exports a GUID and all information related to it in an XML format.
 	 * 
+	 * This function makes use of the "serialise" plugin hook, which is passed an array to which plugins
+	 * should add data to be serialised to.
+	 * 
+	 * @see ElggEntity for an example of its usage.
 	 * @param int $guid The GUID.
 	 * @return xml 
 	 */
 	function export($guid)
 	{
-		// trigger serialise event
-
-		// serialise resultant object
+		global $CONFIG;
+		
+		$guid = (int)$guid;  
+		
+		// Initialise the array
+		$to_be_serialised = array();
+		
+		// Trigger a hook to 
+		$to_be_serialised = trigger_plugin_hook("export", "all", array("guid" => $guid), $to_be_serialised);
+		
+		// Sanity check
+		if (!is_array($to_be_serialised)) throw new ExportException("There was a problem during the serialisation of GUID:$guid");
+		
+		// Now serialise the result to XML
+		$wrapper = new stdClass;
+	
+		// Construct header
+		$wrapper->header = new stdClass;
+		$wrapper->header->date = date("r");
+		$wrapper->header->timestamp = time();
+		$wrapper->header->domain = $CONFIG->wwwroot;
+		$wrapper->header->guid = $guid;
+		$wrapper->header->uuid = guid_to_uuid($guid);
+		$wrapper->header->exported_by = guid_to_uuid($_SESSION['id']);
+		
+		// Construct data
+		$wrapper->data = $to_be_serialised;
+	
+		return serialise_object_to_xml($wrapper, "elggexport");
+		
 
 		/*
 		  	XML will look something like this:
@@ -92,6 +123,86 @@
 	{
 		global $CONFIG;
 		
-		return md5($CONFIG->wwwroot . ":$guid");
+		return "UUID:".md5($CONFIG->wwwroot)  . ":$guid";
 	}
+	
+	/**
+	 * This function serialises an object recursively into an XML representation.
+	 * The function attempts to call $data->export() which expects a stdClass in return, otherwise it will attempt to
+	 * get the object variables using get_object_vars (which will only return public variables!)
+	 * @param $data object The object to serialise.
+	 * @param $n int Level, only used for recursion.
+	 * @return string The serialised XML output.
+	 */
+	function serialise_object_to_xml($data, $name = "", $n = 0)
+	{
+		$classname = ($name=="" ? get_class($data) : $name);
+		
+		$vars = method_exists($data, "export") ? get_object_vars($data->export()) : get_object_vars($data); 
+		
+		$output = "";
+		
+		if (($n==0) || ( is_object($data) && !($data instanceof stdClass))) $output = "<$classname>";
+
+		foreach ($vars as $key => $value)
+		{
+			$output .= "<$key type=\"".gettype($value)."\">";
+			
+			if (is_object($value))
+				$output .= serialise_object_to_xml($value, $key, $n+1);
+			else if (is_array($value))
+				$output .= serialise_array_to_xml($value, $n+1);
+			else
+				$output .= htmlentities($value);
+			
+			$output .= "</$key>\n";
+		}
+		
+		if (($n==0) || ( is_object($data) && !($data instanceof stdClass))) $output .= "</$classname>\n";
+		
+		return $output;
+	}
+
+	/**
+	 * Serialise an array.
+	 *
+	 * @param array $data
+	 * @param int $n Used for recursion
+	 * @return string
+	 */
+	function serialise_array_to_xml(array $data, $n = 0)
+	{
+		$output = "";
+		
+		if ($n==0) $output = "<array>\n";
+		
+		foreach ($data as $key => $value)
+		{
+			$item = "array_item";
+			
+			if (is_numeric($key))
+				$output .= "<$item name=\"$key\" type=\"".gettype($value)."\">";
+			else
+			{
+				$item = $key;
+				$output .= "<$item type=\"".gettype($value)."\">";
+			}
+			
+			if (is_object($value))
+				$output .= serialise_object_to_xml($value, "", $n+1);
+			else if (is_array($value))
+				$output .= serialise_array_to_xml($value, $n+1);
+			else
+				$output .= htmlentities($value);
+			
+			$output .= "</$item>\n";
+		}
+		
+		if ($n==0) $output = "</array>\n";
+		
+		return $output;
+	}
+	
+	class ExportException extends Exception {}
+	class ImportException extends Exception {}
 ?>
\ No newline at end of file