Added permanent store feature

CloudObjects/SDK/ObjectRetriever.php

@@ -43,6 +43,7 @@ class ObjectRetriever implements CustomCacheAndLogInterface {
 	private $defaultReader;
 	private $customCacheDefaultRequest;
 	private $fallbackStoreScope;
+	private $permanentStoreScope;
 
 	const CO_API_URL = 'https://od.coid.link/';
 		
@@ -60,7 +61,9 @@ class ObjectRetriever implements CustomCacheAndLogInterface {
 			'timeout' => 20,
 			'connect_timeout' => 5,
 			'fallback_store_directory' => null,
-			'fallback_store_scope' => null
+			'fallback_store_scope' => null,
+			'permanent_store_directory' => null,
+			'permanent_store_scope' => null
 		], $options);
 
 		// Check object cache configuration
@@ -95,6 +98,27 @@ class ObjectRetriever implements CustomCacheAndLogInterface {
 				: array_map('trim', explode(',', $this->options['fallback_store_scope']));
 		}
 
+		// Check permanent store configuration
+		if (isset($this->options['permanent_store_directory'])
+				&& isset($this->options['permanent_store_scope'])
+				&& !is_dir($this->options['permanent_store_directory'])
+			) {
+			throw new InvalidSDKConfigurationException('Invalid permanent_store_directory specified; must be an existing directory.');
+		}
+
+		if (isset($this->options['permanent_store_directory'])
+				&& isset($this->options['permanent_store_scope'])) {
+			$this->permanentStoreScope = is_array($this->options['permanent_store_scope'])
+				? $this->options['permanent_store_scope']
+				: array_map('trim', explode(',', $this->options['permanent_store_scope']));
+		}
+
+		if (isset($this->fallbackStoreScope) && isset($this->permanentStoreScope)
+				&& realpath($this->options['fallback_store_directory']) === realpath($this->options['permanent_store_directory'])
+			) {
+			throw new InvalidSDKConfigurationException('The permanent_store_directory and the fallback_store_directory must be different directories.');
+		}
+
 		// Set up logger
 		if (is_a($this->options['logger'], LoggerInterface::class)) {
 			$this->setLogger($this->options['logger']);
@@ -180,35 +204,32 @@ class ObjectRetriever implements CustomCacheAndLogInterface {
 		}
 
 		$this->putIntoFallbackStore($id, $data);
+		$this->putIntoPermanentStore($id, $data);
 	}
 
 	/**
-	 * Get the file location of an object in the fallback store, or null if
-	 * the fallback store is not configured or the object is out of scope.
+	 * Get the file location of an object in a store, or null if the store
+	 * is not configured or the object is out of scope.
 	 */
-	private function getFallbackStoreLocation($id) : ?string {
-		if (!isset($this->fallbackStoreScope))
+	private function getStoreLocation($directory, ?array $scope, $id) : ?string {
+		if (!isset($scope))
 			return null;
 
 		// Only objects are stored, not custom data or attachments
 		$coid = new IRI($id);
-		if (!COIDParser::isValidCOID($coid) || $coid->getFragment() !== null || $coid->getQuery() !== null)
+		if (!COIDParser::isValidCOID($coid))
 			return null;
 
-		if (!in_array('*', $this->fallbackStoreScope)
-				&& !in_array($coid->getHost(), $this->fallbackStoreScope))
+		if (!in_array('*', $scope)
+				&& !in_array($coid->getHost(), $scope))
 			return null;
 
-		return $this->options['fallback_store_directory'].DIRECTORY_SEPARATOR.
+		return $directory.DIRECTORY_SEPARATOR.
 			$coid->getHost().str_replace('/', DIRECTORY_SEPARATOR, $coid->getPath())
 			.DIRECTORY_SEPARATOR.'object.jsonld';
 	}
 
-	private function putIntoFallbackStore($id, $data) {
-		$location = $this->getFallbackStoreLocation($id);
-		if (!isset($location))
-			return;
-
+	private function putIntoStore($location, $id, $data, $storeName) {
 		// Write to a temporary file and rename it so that concurrent readers
 		// never see a partially written object
 		$directory = dirname($location);
@@ -218,12 +239,11 @@ class ObjectRetriever implements CustomCacheAndLogInterface {
 				|| !@rename($tempFile, $location)) {
 			@unlink($tempFile);
 			if (isset($this->logger))
-				$this->logger->warning('Could not write <'.$id.'> to fallback store.');
+				$this->logger->warning('Could not write <'.$id.'> to '.$storeName.' store.');
 		}
 	}
 
-	private function getFromFallbackStore($id) : ?string {
-		$location = $this->getFallbackStoreLocation($id);
+	private function getFromStore($location) : ?string {
 		if (!isset($location) || !is_file($location))
 			return null;
 
@@ -231,6 +251,37 @@ class ObjectRetriever implements CustomCacheAndLogInterface {
 		return ($data === false) ? null : $data;
 	}
 
+	private function getFallbackStoreLocation($id) : ?string {
+		return $this->getStoreLocation($this->options['fallback_store_directory'],
+			$this->fallbackStoreScope, $id);
+	}
+
+	private function putIntoFallbackStore($id, $data) {
+		$location = $this->getFallbackStoreLocation($id);
+		if (isset($location))
+			$this->putIntoStore($location, $id, $data, 'fallback');
+	}
+
+	private function getFromFallbackStore($id) : ?string {
+		return $this->getFromStore($this->getFallbackStoreLocation($id));
+	}
+
+	private function getPermanentStoreLocation($id) : ?string {
+		return $this->getStoreLocation($this->options['permanent_store_directory'],
+			$this->permanentStoreScope, $id);
+	}
+
+	private function putIntoPermanentStore($id, $data) {
+		// Objects in the permanent store are never overwritten
+		$location = $this->getPermanentStoreLocation($id);
+		if (isset($location) && !is_file($location))
+			$this->putIntoStore($location, $id, $data, 'permanent');
+	}
+
+	private function getFromPermanentStore($id) : ?string {
+		return $this->getFromStore($this->getPermanentStoreLocation($id));
+	}
+
 	public function getFromCacheCustom($id) {
 		return $this->getFromCache('custom/'.$id);
 	}
@@ -343,6 +394,12 @@ class ObjectRetriever implements CustomCacheAndLogInterface {
 				$this->logInfoWithTime('Fetched <'.$uriString.'> from object cache.', $ts);
 		}
 
+		if (!isset($object)) {
+			$object = $this->getFromPermanentStore($uriString);
+			if (isset($object))
+				$this->logInfoWithTime('Fetched <'.$uriString.'> from permanent store.', $ts);
+		}
+
 		if (!isset($object)) {
 			try {
 				$response = $this->client