Model some SAML errors as exceptions in the SAML module.

This makes it easier to identify error conditions and return errors to an SP. More known errors should also be added here.

modules/saml/lib/Error/NoAuthnContext.php

+<?php
+/**
+ * A SAML error indicating that none of the requested Authentication Contexts can be used.
+ *
+ * @author Jaime Pérez Crespo, UNINETT AS <jaime.perez@uninett.no>
+ * @package SimpleSAMLphp
+ */
+
+namespace SimpleSAML\Module\saml\Error;
+
+use SAML2\Constants;
+
+class NoAuthnContext extends \sspmod_saml_Error
+{
+    /**
+     * NoAuthnContext error constructor.
+     *
+     * @param string $responsible A string telling who is responsible for this error. Can be one of the following:
+     *   - \SAML2\Constants::STATUS_RESPONDER: in case the error is caused by this SAML responder.
+     *   - \SAML2\Constants::STATUS_REQUESTER: in case the error is caused by the SAML requester.
+     * @param string|null $message A short message explaining why this error happened.
+     * @param \Exception|null $cause An exception that caused this error.
+     */
+    public function __construct($responsible, $message = null, \Exception $cause = null)
+    {
+        parent::__construct($responsible, Constants::STATUS_NO_AUTHN_CONTEXT, $message, $cause);
+    }
+}

modules/saml/lib/Error/NoAvailableIDP.php

+<?php
+/**
+ * A SAML error indicating that none of the requested IdPs can be used.
+ *
+ * @author Jaime Pérez Crespo, UNINETT AS <jaime.perez@uninett.no>
+ * @package SimpleSAMLphp
+ */
+
+namespace SimpleSAML\Module\saml\Error;
+
+use SAML2\Constants;
+
+class NoAvailableIDP extends \sspmod_saml_Error
+{
+    /**
+     * NoAvailableIDP error constructor.
+     *
+     * @param string $responsible A string telling who is responsible for this error. Can be one of the following:
+     *   - \SAML2\Constants::STATUS_RESPONDER: in case the error is caused by this SAML responder.
+     *   - \SAML2\Constants::STATUS_REQUESTER: in case the error is caused by the SAML requester.
+     * @param string|null $message A short message explaining why this error happened.
+     * @param \Exception|null $cause An exception that caused this error.
+     */
+    public function __construct($responsible, $message = null, \Exception $cause = null)
+    {
+        parent::__construct($responsible, Constants::STATUS_NO_AVAILABLE_IDP, $message, $cause);
+    }
+}

modules/saml/lib/Error/NoPassive.php

+<?php
+/**
+ * A SAML error indicating that passive authentication cannot be used.
+ *
+ * @author Jaime Pérez Crespo, UNINETT AS <jaime.perez@uninett.no>
+ * @package SimpleSAMLphp
+ */
+
+namespace SimpleSAML\Module\saml\Error;
+
+use SAML2\Constants;
+
+class NoPassive extends \sspmod_saml_Error
+{
+    /**
+     * NoPassive error constructor.
+     *
+     * @param string $responsible A string telling who is responsible for this error. Can be one of the following:
+     *   - \SAML2\Constants::STATUS_RESPONDER: in case the error is caused by this SAML responder.
+     *   - \SAML2\Constants::STATUS_REQUESTER: in case the error is caused by the SAML requester.
+     * @param string|null $message A short message explaining why this error happened.
+     * @param \Exception|null $cause An exception that caused this error.
+     */
+    public function __construct($responsible, $message = null, \Exception $cause = null)
+    {
+        parent::__construct($responsible, Constants::STATUS_NO_PASSIVE, $message, $cause);
+    }
+}

modules/saml/lib/Error/NoSupportedIDP.php

+<?php
+/**
+ * A SAML error indicating that none of the IdPs requested are supported.
+ *
+ * @author Jaime Pérez Crespo, UNINETT AS <jaime.perez@uninett.no>
+ * @package SimpleSAMLphp
+ */
+
+namespace SimpleSAML\Module\saml\Error;
+
+use SAML2\Constants;
+
+class NoSupportedIDP extends \sspmod_saml_Error
+{
+    /**
+     * NoSupportedIDP error constructor.
+     *
+     * @param string $responsible A string telling who is responsible for this error. Can be one of the following:
+     *   - \SAML2\Constants::STATUS_RESPONDER: in case the error is caused by this SAML responder.
+     *   - \SAML2\Constants::STATUS_REQUESTER: in case the error is caused by the SAML requester.
+     * @param string|null $message A short message explaining why this error happened.
+     * @param \Exception|null $cause An exception that caused this error.
+     */
+    public function __construct($responsible, $message = null, \Exception $cause = null)
+    {
+        parent::__construct($responsible, Constants::STATUS_NO_SUPPORTED_IDP, $message, $cause);
+    }
+}

modules/saml/lib/Error/ProxyCountExceeded.php

+<?php
+/**
+ * A SAML error indicating that the maximum amount of proxies traversed has been reached.
+ *
+ * @author Jaime Pérez Crespo, UNINETT AS <jaime.perez@uninett.no>
+ * @package SimpleSAMLphp
+ */
+
+namespace SimpleSAML\Module\saml\Error;
+
+use SAML2\Constants;
+
+class ProxyCountExceeded extends \sspmod_saml_Error
+{
+    /**
+     * ProxyCountExceeded error constructor.
+     *
+     * @param string $responsible A string telling who is responsible for this error. Can be one of the following:
+     *   - \SAML2\Constants::STATUS_RESPONDER: in case the error is caused by this SAML responder.
+     *   - \SAML2\Constants::STATUS_REQUESTER: in case the error is caused by the SAML requester.
+     * @param string|null $message A short message explaining why this error happened.
+     * @param \Exception|null $cause An exception that caused this error.
+     */
+    public function __construct($responsible, $message = null, \Exception $cause = null)
+    {
+        parent::__construct($responsible, Constants::STATUS_PROXY_COUNT_EXCEEDED, $message, $cause);
+    }
+}