Marcus Povey <marcus@dushka.co.uk>

* Namespace support added to export

git-svn-id: https://code.elgg.org/elgg/trunk@521 36083f99-b078-4883-b0ff-0f9b5a30f544

1 files changed, 149 insertions, 20 deletions

diff --git a/engine/lib/export.php b/engine/lib/export.php
index 279d3e8a6..93c7dc129 100644
--- a/engine/lib/export.php
+++ b/engine/lib/export.php
@@ -61,12 +61,11 @@
 	class ImportException extends DataFormatException {}
 	
 	/**
-	 * Open Data Definition (ODD) superclass.
-	 * @package Elgg
-	 * @subpackage Core
+	 * @class ODDDocument ODD Document container.
+	 * This class is used during import and export to construct.
 	 * @author Marcus Povey
 	 */
-	abstract class ODD
+	class ODDDocument
 	{
 		/**
 		 * ODD Version
@@ -76,6 +75,88 @@
 		private $ODDSupportedVersion = "1.0"; 
 		
 		/**
+		 * Elements of the document.
+		 */
+		private $elements;
+		
+		public function __construct(array $elements = NULL)
+		{
+			if ($elements)
+				$this->elements = $elements;
+			else
+				$this->elements = array();
+		}
+		
+		/**
+		 * Return the version of ODD being used.
+		 *
+		 * @return string
+		 */
+		public function getVersion() { return $this->ODDSupportedVersion; }
+		
+		public function addElement(ODD $element) { $this->elements[] = $element; }
+		public function addElements(array $elements)
+		{
+			foreach ($elements as $element)
+				$this->addElement($element);
+		}
+		
+		public function getElements() { return $this->elements; }
+		
+		/**
+		 * Magic function to generate valid ODD XML for this item.
+		 */
+		public function __toString()
+		{
+			$xml = "";
+			$namespaces = "";
+			$elements_xml = "";
+	
+			// Get XML and catalog namespaces
+			foreach ($this->elements as $element)
+			{
+				$elements_xml .= "$element";
+				
+				// Lookup namespace and get prefix
+				$ns = $element->getNamespace();
+				if (($ns) && (strpos($namespaces, $ns)===false))
+				{
+					$prefix = register_odd_extension_namespace($ns); // cheating... will return a prefix no matter what.
+					$namespaces .= " xmlns:$prefix=\"$ns\"";
+				}
+				else
+					trigger_error("'".get_class($element)."' has no namespace attached.", E_USER_WARNING);
+			}
+			
+			// Output begin tag
+			$generated = date("r");
+			$xml .= "<odd version=\"{$this->ODDSupportedVersion}\" generated=\"$generated\" $namespaces>\n";
+
+			// output elements
+			$xml .= $elements_xml;
+			
+			// Output end tag
+			$xml .= "</odd>\n";	
+			
+			return $xml;
+		}
+	}
+	
+	
+	/**
+	 * Open Data Definition (ODD) superclass.
+	 * @package Elgg
+	 * @subpackage Core
+	 * @author Marcus Povey
+	 */
+	abstract class ODD
+	{
+		/**
+		 * Namespace defining the ODD extension being used, optional but highly recommended.
+		 */
+		private $namespace;
+		
+		/**
 		 * Attributes.
 		 */
 		private $attributes = array();
@@ -103,13 +184,8 @@
 		}
 		public function setBody($value) { $this->body = $value; }
 		public function getBody() { return $this->body; }
-		
-		/**
-		 * Return the version of ODD being used.
-		 *
-		 * @return real
-		 */
-		public function getVersion() { return $this->ODDSupportedVersion; }
+		public function setNamespace($namespace) { $this->namespace = $namespace; }
+		public function getNamespace() { return $this->namespace; }
 		
 		/**
 		 * For serialisation, implement to return a string name of the tag eg "header" or "metadata".
@@ -122,6 +198,11 @@
 		 */
 		public function __toString()
 		{
+			// Namespace mapping
+			$ns = "";
+			if ($this->getNamespace()!="")
+				$ns = register_odd_extension_namespace($this->getNamespace()) . ":"; // Short way: if it has been registered already we'll get back a prefix, if not it'll generate one and return.
+			
 			// Construct attributes
 			$attr = "";
 			foreach ($this->attributes as $k => $v)
@@ -132,9 +213,9 @@
 			
 			$end = "/>";
 			if ($body!="")
-				$end = ">$body</$tag>";
+				$end = ">$body</{$ns}{$tag}>";
 			
-			return "<$tag $attr" . $end . "\n";  
+			return "<{$ns}{$tag} $attr" . $end . "\n";  
 		}
 	}
 	
@@ -233,6 +314,59 @@
 		return $odd;
 	}
 	
+	/** ODD Namespaces & registered extension **/
+	$ODD_EXTENSION_NAMESPACES = array();
+	
+	/**
+	 * This function registers a namespace prefix with a given extension.
+	 * Use this function to register a friendly prefix against a namespace. Namespaces will
+	 * still function if you don't use this function however this gives you the opportunity to
+	 * register a more human readable name.
+	 * 
+	 * @param string $extension_url The namespace URL as given in the extension spec.
+	 * @param string $namespace_prefix The chosen prefix, if this is blank then one is generated.
+	 * @return string The extension prefix to be used, either $namespace_prefix, an already registered prefix or a generated one.
+	 */
+	function register_odd_extension_namespace($extension_url, $namespace_prefix = "")
+	{
+		global $ODD_EXTENSION_NAMESPACES;
+		
+		if (isset($ODD_EXTENSION_NAMESPACES[$extension_url]))
+			return $ODD_EXTENSION_NAMESPACES[$extension_url];
+			
+		if ($namespace_prefix == "")
+		{
+			do 
+			{
+				$namespace_prefix = substr(strtolower(base64_encode(md5(mt_rand()))), 0, 8);
+			}
+			while (
+				(array_key_exists($namespace_prefix, $ODD_EXTENSION_NAMESPACES)) || 
+				(is_numeric($namespace_prefix[0]))
+				); // TODO: Do this better, but i'm quite tired now...
+		}
+			
+		$ODD_EXTENSION_NAMESPACES[$extension_url] = $namespace_prefix;
+		
+		return $ODD_EXTENSION_NAMESPACES[$extension_url];
+	}
+	
+	/**
+	 * Get a named prefix.
+	 * 
+	 * @param string $extension_url The namespace URL as given in the extension spec.
+	 * @return mixed The prefix associated with the given extension or false;
+	 */
+	function get_odd_namespace_prefix($extension_url)
+	{
+		global $ODD_EXTENSION_NAMESPACES;
+		
+		if (isset($ODD_EXTENSION_NAMESPACES[$extension_url]))
+			return $ODD_EXTENSION_NAMESPACES[$extension_url];
+		
+		return false;
+	}
+	
 	/** Relationship verb mapping */
 	$ODD_RELATIONSHIP_VERBS = array();
 	
@@ -401,14 +535,9 @@
 		// Sanity check
 		if ((!is_array($to_be_serialised)) || (count($to_be_serialised)==0)) throw new ExportException("No such entity GUID:$guid");
 		
-		$output = "<odd>\n";
-		
-		foreach ($to_be_serialised as $odd)
-			$output .= "$odd";
-		
-		$output .= "</odd>\n";
+		$odd = new ODDDocument($to_be_serialised);
 		
-		return $output;
+		return "$odd";
 	}
 	
 	/**