Add an abstract class for OIDC based integration

- it's abstract because the idea is that it will be extended by
  specific, non-abstract, classes - like a token class to handle
  EOSC AAI.

Author: gregcorbett

lib/Authentication/AuthTokens/OIDCAuthToken.php

@@ -0,0 +1,100 @@
+<?php
+
+namespace org\gocdb\security\authentication;
+
+require_once __DIR__ . '/../IAuthentication.php';
+
+abstract class OIDCAuthToken implements IAuthentication
+{
+    private $userDetails = null;
+    private $authorities = array();
+    private $principal;
+
+    /**
+     * {@see IAuthentication::eraseCredentials()}
+     */
+    public function eraseCredentials()
+    {
+    }
+
+    /**
+     * {@see IAuthentication::getAuthorities()}
+     */
+    public function getAuthorities()
+    {
+        return $this->authorities;
+    }
+
+    /**
+     * {@see IAuthentication::getCredentials()}
+     * @return string An empty string as passwords are not used by this token.
+     */
+    public function getCredentials()
+    {
+        return ""; // none used in this token, handled by IdP
+    }
+
+    /**
+     * A custom object used to store additional user details.
+     * Allows non-security related user information (such as email addresses,
+     * telephone numbers etc) to be stored in a convenient location.
+     * {@see IAuthentication::getDetails()}
+     *
+     * @return Object or null if not used
+     */
+    public function getDetails()
+    {
+        return $this->userDetails;
+    }
+
+    /**
+     * {@see IAuthentication::getPrinciple()}
+     * @return string unique principle string of user
+     */
+    public function getPrinciple()
+    {
+        return $this->principal;
+    }
+
+    /**
+     * {@see IAuthentication::setAuthorities($authorities)}
+     */
+    public function setAuthorities($authorities)
+    {
+        $this->authorities = $authorities;
+    }
+
+    /**
+     * {@see IAuthentication::setDetails($userDetails)}
+     * @param Object $userDetails
+     */
+    public function setDetails($userDetails)
+    {
+        $this->userDetails = $userDetails;
+    }
+
+    /**
+     * {@see IAuthentication::validate()}
+     */
+    public function validate()
+    {
+    }
+
+    /**
+     * {@see IAuthentication::isPreAuthenticating()}
+     */
+    public static function isPreAuthenticating()
+    {
+        return true;
+    }
+
+    /**
+     * Returns true, this token reads the session attributes and so
+     * does not need to be stateful itself.
+     * {@see IAuthentication::isStateless()}
+     */
+    public static function isStateless()
+    {
+        return true;
+    }
+}