feat(oauth2): simple userinfo endpoint

apps/oauth2/appinfo/routes.php

@@ -43,5 +43,10 @@
 			'url' => '/api/v1/token',
 			'verb' => 'POST'
 		],
+		[
+			'name' => 'OauthApi#getUserInfo',
+			'url' => '/api/v1/userinfo',
+			'verb' => 'GET'
+		],
 	],
 ];

apps/oauth2/lib/Controller/OauthApiController.php

@@ -41,6 +41,8 @@
 use OCP\Authentication\Exceptions\InvalidTokenException;
 use OCP\DB\Exception;
 use OCP\IRequest;
+use OCP\IUserSession;
+use OCP\IURLGenerator;
 use OCP\Security\Bruteforce\IThrottler;
 use OCP\Security\ICrypto;
 use OCP\Security\ISecureRandom;
@@ -62,6 +64,8 @@ public function __construct(
 		private LoggerInterface $logger,
 		private IThrottler $throttler,
 		private ITimeFactory $timeFactory,
+		private IUserSession $userSession,
+		private IURLGenerator $urlGenerator,
 	) {
 		parent::__construct($appName, $request);
 	}
@@ -226,4 +230,32 @@ public function getToken(
 			]
 		);
 	}
+
+	/**
+	 * @PublicPage
+	 * @NoCSRFRequired
+	 *
+	 * @return JSONResponse
+	 */
+	public function getUserInfo() {
+		$user = $this->userSession->getUser();
+		if ($user) {
+			$displayName = $user->getDisplayName();
+			$partedName = explode(' ', $displayName);
+			$userId = $user->getUID();
+			$response = new JSONResponse([
+				'sub' => $userId,
+				'name' => $displayName,
+				'given_name' => $partedName[0],
+				'family_name' => $partedName[1] ?? $partedName[0],
+				'email' => $user->getEMailAddress(),
+				'picture' => $this->urlGenerator->getAbsoluteURL("index.php/avatar/$userId/512"),
+			]);
+		}else{
+			$response = new JSONResponse([
+				'error' => 'user_not_found',
+			], Http::STATUS_NOT_FOUND);
+		}
+		return $response;
+	}
 }