From fdbcba8fc19d35aa9116ca4d132908bcf23dd64a Mon Sep 17 00:00:00 2001
From: Simon Rettberg
Date: Mon, 17 Jun 2024 16:08:55 +0200
Subject: [dozmod] Add support for CoW API

---
 modules-available/dozmod/api.inc.php | 34 +++++++++++++++++++++++++---------
 1 file changed, 25 insertions(+), 9 deletions(-)

diff --git a/modules-available/dozmod/api.inc.php b/modules-available/dozmod/api.inc.php
index b5030cc5..34b5136d 100644
--- a/modules-available/dozmod/api.inc.php
+++ b/modules-available/dozmod/api.inc.php
@@ -156,6 +156,7 @@ function getListForLocations(array $locationIds, bool $raw)
 		 to be in "exam-mode" and only offer him exams (no lectures) */
 	$key = 'lectures_' . cache_hash($locationIds);
 	$examMode = Request::get('exams', 'normal-mode', 'string') !== 'normal-mode';
+	$cow = Request::get('cow-user', null, 'string');
 	$clientServerMismatch = false;
 	if (Module::isAvailable('exams')) {
 		// If we have the exam mode module, we can enforce a server side check and make sure it agrees with the client
@@ -176,16 +177,21 @@ function getListForLocations(array $locationIds, bool $raw)
 	$rawKey = $key . '_raw';
 	if ($raw) {
 		Header('Content-Type: text/xml; charset=utf-8');
-		if (cache_has($rawKey)) {
+		if ($cow === null && cache_has($rawKey)) {
 			cache_get_passthru($rawKey);
 		}
-	} elseif (cache_has($key)) {
+	} elseif ($cow === null && cache_has($key)) {
 		return unserialize(cache_get($key));
 	}
 	// Not in cache
 	$url = LIST_URL . "?locations=" . implode('%20', $locationIds);
 	if ($examMode) {
 		$url .= '&exams';
+	} else {
+		// Only allow CoW in non-exam environment
+		if ($cow !== null) {
+			$url .= '&cow-user=' . urlencode($cow);
+		}
 	}
 	$t = microtime(true);
 	$value = Download::asString($url, 60, $code);
@@ -195,9 +201,11 @@ function getListForLocations(array $locationIds, bool $raw)
 	}
 	if ($value === false || $code < 200 || $code > 299)
 		return false;
-	cache_put($rawKey, $value);
 	$list = xmlToLectureIds($value);
-	cache_put($key, serialize($list));
+	if ($cow === null) {
+		cache_put($rawKey, $value);
+		cache_put($key, serialize($list));
+	}
 	if ($raw) {
 		die($value);
 	}
@@ -214,12 +222,16 @@ function outputLectureXmlForLocation(array $locationIds)
 	return getListForLocations($locationIds, true);
 }
 
-function _getVmData(string $lecture_uuid, string $subResource = null)
+function _getVmData(string $lecture_uuid, string $subResource = null, string $cowUser = null)
 {
 	$url = VMX_URL . '/' . $lecture_uuid;
 	if ($subResource !== null) {
 		$url .= '/' . $subResource;
 	}
+	if ($cowUser !== null) {
+		$url .= '?cow-user=' . urlencode($cowUser);
+		$url .= '&cow-type=' . urlencode(Request::get('cow-type', '', 'string'));
+	}
 	$t = microtime(true);
 	$response = Download::asString($url, 60, $code);
 	$t = microtime(true) - $t;
@@ -236,15 +248,17 @@ function _getVmData(string $lecture_uuid, string $subResource = null)
 /** Caching wrapper around _getVmData() **/
 function outputResource(string $lecture_uuid, string $resource): void
 {
+	$key = $resource . '_' . $lecture_uuid;
 	if ($resource === 'metadata') {
 		// HACK: config.tgz is compressed, don't use gzip output handler
 		@ob_end_clean();
 		Header('Content-Type: application/gzip');
+		$cow = Request::get('cow-user', null, 'string');
 	} else {
 		Header('Content-Type: text/plain; charset=utf-8');
+		$cow = null;
 	}
-	$key = $resource . '_' . $lecture_uuid;
-	if (cache_has($key)) {
+	if ($cow === null && cache_has($key)) {
 		if ($resource === 'metadata' || $resource === 'vmx') {
 			// HACK HACK HACK: Update launch counter as it was cached,
 			// otherwise dmsd would take care of increasing it...
@@ -253,14 +267,16 @@ function outputResource(string $lecture_uuid, string $resource): void
 		}
 		cache_get_passthru($key);
 	} else {
-		$value = _getVmData($lecture_uuid, $resource);
+		$value = _getVmData($lecture_uuid, $resource, $cow);
 		if ($value === false)
 			return;
 		if (is_int($value)) {
 			http_response_code($value);
 			exit;
 		}
-		cache_put($key, $value);
+		if  ($cow === null) {
+			cache_put($key, $value);
+		}
 		die($value);
 	}
 }
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