Discovery: Add a memory cache in CollaboraDiscovery for the parsed xml.

src/Discovery/CollaboraDiscovery.php

@@ -15,22 +15,24 @@
 namespace Drupal\collabora_online\Discovery;
 
 use Drupal\collabora_online\Exception\CollaboraNotAvailableException;
+use Drupal\Component\Datetime\TimeInterface;
+use Drupal\Core\Cache\Cache;
 use Drupal\Core\Cache\CacheableMetadata;
+use Drupal\Core\Cache\MemoryCache\MemoryCacheInterface;
 use Symfony\Component\ErrorHandler\ErrorHandler;
 
 /**
  * Service to get values from the discovery.xml.
  */
 class CollaboraDiscovery implements CollaboraDiscoveryInterface {
 
-  /**
-   * Constructor.
-   *
-   * @param \Drupal\collabora_online\Discovery\CollaboraDiscoveryFetcherInterface $discoveryFetcher
-   *   Service to load the discovery.xml from the Collabora server.
-   */
+  protected const DEFAULT_CID = 'collabora_online.discovery.parsed';
+
   public function __construct(
     protected readonly CollaboraDiscoveryFetcherInterface $discoveryFetcher,
+    protected readonly MemoryCacheInterface $cache,
+    protected readonly TimeInterface $time,
+    protected readonly string $cid = self::DEFAULT_CID,
   ) {}
 
   /**
@@ -75,9 +77,26 @@ public function getProofKeyOld(): ?string {
    *   Fetching the discovery.xml failed, or the result is not valid xml.
    */
   protected function getParsedXml(): \SimpleXMLElement {
+    $cached = $this->cache->get($this->cid);
+    if ($cached) {
+      return $cached->data;
+    }
     $cacheability = new CacheableMetadata();
     $xml = $this->discoveryFetcher->getDiscoveryXml($cacheability);
-    return $this->parseXml($xml);
+    $parsed_xml = $this->parseXml($xml);
+
+    $max_age = $cacheability->getCacheMaxAge();
+    /* @see \Drupal\Core\Cache\VariationCache::maxAgeToExpire() */
+    $expire = ($max_age === Cache::PERMANENT)
+      ? Cache::PERMANENT
+      : $max_age + $this->time->getRequestTime();
+    $this->cache->set(
+      $this->cid,
+      $parsed_xml,
+      $expire,
+      $cacheability->getCacheTags(),
+    );
+    return $parsed_xml;
   }
 
   /**

tests/src/Unit/CollaboraDiscoveryTest.php

@@ -8,6 +8,8 @@
 use Drupal\collabora_online\Discovery\CollaboraDiscoveryFetcherInterface;
 use Drupal\collabora_online\Discovery\CollaboraDiscoveryInterface;
 use Drupal\collabora_online\Exception\CollaboraNotAvailableException;
+use Drupal\Component\Datetime\Time;
+use Drupal\Core\Cache\MemoryCache\MemoryCache;
 use Drupal\Tests\UnitTestCase;
 
 /**
@@ -146,7 +148,12 @@ protected function getDiscoveryFromFile(string $file): CollaboraDiscoveryInterfa
   protected function getDiscoveryFromXml(string $xml): CollaboraDiscoveryInterface {
     $fetcher = $this->createMock(CollaboraDiscoveryFetcherInterface::class);
     $fetcher->method('getDiscoveryXml')->willReturn($xml);
-    return new CollaboraDiscovery($fetcher);
+    $time = new Time();
+    return new CollaboraDiscovery(
+      $fetcher,
+      new MemoryCache($time),
+      $time,
+    );
   }
 
 }