Use TTL for in-memory cache to support long-lived instances

CloudObjects/SDK/ObjectRetriever.php

@@ -35,9 +35,9 @@ class ObjectRetriever implements CustomCacheAndLogInterface {
 
 	private $client;
 	private $prefix;
-	private $options;
+	private $options = [];
 	private $cache;
-	private $objects;
+	private $objects = [];
 	private $defaultReader;
 	private $customCacheDefaultRequest;
 
@@ -245,12 +245,16 @@ class ObjectRetriever implements CustomCacheAndLogInterface {
 
 		$uriString = (string)$coid;
 
-		if (isset($this->objects[$uriString]))
-			// Return from in-memory cache if it exists
-			return $this->objects[$uriString];
+		$this->removeExpiredFromInMemoryCache();
 
 		$ts = microtime(true);
 
+		if (isset($this->objects[$uriString])) {
+			// Return from in-memory cache if it exists
+			$this->logInfoWithTime('Returning previous node for <'.$uriString.'>.', $ts);
+			return $this->objects[$uriString][1];
+		}
+
 		if (isset($this->options['static_config_path'])) {
 			$location = realpath($this->options['static_config_path'].DIRECTORY_SEPARATOR.
 				$coid->getHost().str_replace('/', DIRECTORY_SEPARATOR, $coid->getPath())
@@ -287,8 +291,8 @@ class ObjectRetriever implements CustomCacheAndLogInterface {
 		}
 
 		$document = JsonLD::getDocument($object);
-		$this->objects[$uriString] = $document->getGraph()->getNode($uriString);
-		return $this->objects[$uriString];
+		$this->objects[$uriString] = [ time(), $document->getGraph()->getNode($uriString) ];
+		return $this->objects[$uriString][1];
 	}
 
 	/**
@@ -325,7 +329,7 @@ class ObjectRetriever implements CustomCacheAndLogInterface {
 				if (!COIDParser::isValidCOID($iri)) continue;
 				if ($iri->getHost() != $namespaceCoid->getHost()) continue;
 
-				$this->objects[$object->getId()] = $object;
+				$this->objects[$object->getId()] = [ time(), $object ];
 				$this->putIntoCache($object->getId(), $object, $this->options['cache_ttl']);
 				$allIris[] = $iri;
 			}
@@ -366,7 +370,7 @@ class ObjectRetriever implements CustomCacheAndLogInterface {
 				if (!COIDParser::isValidCOID($iri)) continue;
 					if ($iri->getHost() != $namespaceCoid->getHost()) continue;
 
-				$this->objects[$object->getId()] = $object;
+				$this->objects[$object->getId()] = [ time(), $object ];
 				$this->putIntoCache($object->getId(), $object, $this->options['cache_ttl']);
 				$allIris[] = $iri;
 			}
@@ -441,7 +445,7 @@ class ObjectRetriever implements CustomCacheAndLogInterface {
 			$document = JsonLD::getDocument((string)$response->getBody());
 			$containerNode = $document->getGraph()->getNode('co-namespace-members://'.$namespaceCoid->getHost());
 			
-			$reader = new NodeReader([ 'prefixes' => [ 'rdfs' => 'http://www.w3.org/2000/01/rdf-schema#' ]]);		
+			$reader = new NodeReader([ 'prefixes' => [ 'rdfs' => 'http://www.w3.org/2000/01/rdf-schema#' ]]);
 			$allIris = $reader->getAllValuesIRI($containerNode, 'rdfs:member');
 		
 			$this->logInfoWithTime('Fetched object list with <'.$type.'> for <'.$namespaceCoid->getHost().'> from Core API ['.$response->getStatusCode().'].', $ts);
@@ -560,4 +564,27 @@ class ObjectRetriever implements CustomCacheAndLogInterface {
 		return $this->getCloudObject($this->assertAuthenticatingNamespaceAndGetId());
 	}
 
+	/**
+	 * Remove expired objects from the in-memory cache. Does not affect external cache.
+	 */
+	public function removeExpiredFromInMemoryCache() {
+		$expiryThreshold = time() - $this->options['cache_ttl'];
+
+		foreach ($this->objects as $uriString => $entry) {
+			if ($entry[0] < $expiryThreshold) {
+				unset($this->objects[$uriString]);
+			}
+		}
+
+		return $this;
+	}
+
+	/**
+	 * Remove all entries from the in-memory cache. Does not affect external cache.
+	 */
+	public function clearInMemoryCache() {
+		$this->objects = [];
+		return $this;
+	}
+
 }