Start with EntityStatement controller

UPGRADE.md

@@ -7,6 +7,8 @@
 - TODO implement store for different entities?: i.e. client data can use RDB like mysql, whilst short term data
   like tokens can utilize faster stores like memcache, redis...
 - TODO move to SimpleSAMLphp ProcessingChain
+- TODO OpenID Federation capabilities
+  - [ ] Expose OP configuration entity statement (statement about itself)
 
 ## Major impact changes
 - TODO move away from SSP database as store; move to custom store interface

routing/routes/routes.yml

@@ -6,4 +6,10 @@
 
 openid-configuration:
   path: openid-configuration
-  controller: SimpleSAML\Module\oidc\Controller\ConfigurationDiscoveryController
+  controller: SimpleSAML\Module\oidc\Controller\ConfigurationDiscoveryController
+
+# Federation related routes
+# https://openid.net/specs/openid-federation-1_0.html#name-federation-entity-configura
+openid-federation-entity-statement-configuration:
+  path: openid-federation
+  controller: SimpleSAML\Module\oidc\Controller\Federation\EntityStatementController::configuration

src/Controller/Federation/EntityStatementController.php

@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SimpleSAML\Module\oidc\Controller\Federation;
+
+use SimpleSAML\Module\oidc\Services\JsonWebTokenBuilderService;
+use SimpleSAML\Module\oidc\Services\OpMetadataService;
+use Symfony\Component\HttpFoundation\Response;
+
+class EntityStatementController
+{
+    public function __construct(
+        private readonly JsonWebTokenBuilderService $jsonWebTokenBuilderService,
+        private readonly OpMetadataService $opMetadataService,
+    ) {
+    }
+
+    /**
+     * Return the JWS with the OP configuration statement. openid-federation
+     * @return Response
+     */
+    public function configuration(): Response
+    {
+        // TODO mivanci Adjust JsonWebTokenBuilderService to accommodate new federation capabilities
+        $jws = '';
+        return new Response($jws);
+    }
+}