New filter: core:ScopeFromAttribute

Retrieve a scope from a source attribute and add it as a virtual target
attribute.

Filter created by Thomas Zangerl <thomas.zangerl@freenet.de>

git-svn-id: https://simplesamlphp.googlecode.com/svn/trunk@2218 44740490-163a-0410-bde0-09ae8108e29a

modules/core/lib/Auth/Process/ScopeFromAttribute.php

+<?php
+
+/**
+ * Retrieve a scope from a source attribute and add it as a virtual target
+ * attribute.
+ *
+ * For instance, add the following to $simplesamldir/config.php, entry
+ * authproc.sp
+ *
+ * 51 => array(
+ *             'class'         => 'core:ScopeFromAttribute',
+ *             'sourceAttribute' => 'eduPersonPrincipalName',
+ *             'targetAttribute' => 'scope',
+ * ),
+ *
+ * to add a virtual 'scope' attribute from the eduPersonPrincipalName
+ * attribute.
+ */
+class sspmod_core_Auth_Process_ScopeFromAttribute extends SimpleSAML_Auth_ProcessingFilter {
+	/**
+	 * The attribute where the scope is taken from
+	 *
+	 * @var string
+	 */
+	private $sourceAttribute;
+	/**
+	 * The name of the attribute which includes the scope
+	 *
+	 * @var string
+	 */
+	private $targetAttribute;
+
+	/**
+	 * Initialize this filter, parse configuration
+	 *
+	 * @param array $config  Configuration information about this filter.
+	 * @param mixed $reserved  For future use.
+	 */
+	public function __construct($config, $reserved) {
+		parent::__construct($config, $reserved);
+		assert('is_array($config)');
+
+		$config = SimpleSAML_Configuration::loadFromArray($config, 'ScopeFromAttribute');
+		$this->targetAttribute = $config->getString('targetAttribute');
+		$this->sourceAttribute = $config->getString('sourceAttribute');
+	} /* end constructor */
+
+
+	/**
+	 * Apply this filter.
+	 *
+	 * @param array &$request  The current request
+	 */
+	public function process(&$request) {
+		assert('is_array($request)');
+		assert('array_key_exists("Attributes", $request)');
+
+		$attributes =& $request['Attributes'];
+
+		if (!isset($attributes[$this->sourceAttribute])) {
+			return;
+		}
+
+		/* will not overwrite existing attribute */
+		if (isset($attributes[$this->targetAttribute])) {
+			return;
+		}
+
+		$sourceAttrVal = $attributes[$this->sourceAttribute][0];
+
+		/* the last position of an @ is usually the beginning of the scope
+		 * string */
+		$scopeIndex = strrpos($sourceAttrVal, '@');
+
+		if ($scopeIndex !== FALSE) {
+			$attributes[$this->targetAttribute] = array();
+			$scope = substr($sourceAttrVal, $scopeIndex+1);
+			$attributes[$this->targetAttribute][] = $scope;
+			SimpleSAML_Logger::debug('ScopeFromAttribute: Inserted new attribute ' .
+			                         $this->targetAttribute . ', with scope ' .
+			                         $scope);
+		} else {
+			SimpleSAML_Logger::warning('ScopeFromAttribute: The configured source attribute ' .
+			                           $this->sourceAttribute .
+			                           ' does not have a scope. Did not add attribute ' .
+			                           $this->targetAttribute . '.');
+		}
+	} /* end process */
+}