Minor refactoring to avoid deprecated function

CloudObjects/SDK/ObjectRetriever.php

@@ -635,10 +635,10 @@ class ObjectRetriever implements CustomCacheAndLogInterface {
 	 */
 	public function get($coid) {
 		if (is_string($coid))
-			return $this->getObject(new IRI($coid));
+			return $this->getObjectNode(new IRI($coid));
 
 		if (is_object($coid) && get_class($coid)=='ML\IRI\IRI')
-			return $this->getObject($coid);
+			return $this->getObjectNode($coid);
 
 		throw new SDKException('COID must be passed as a string or an IRI object.');
 	}
@@ -650,7 +650,7 @@ class ObjectRetriever implements CustomCacheAndLogInterface {
 	 * @param string $filename
 	 */
 	public function getAttachment(IRI $coid, $filename) {
-		$object = $this->getObject($coid);
+		$object = $this->getObjectNode($coid);
 
 		if (!$object)
 			// Cannot get attachment for non-existing object
@@ -687,7 +687,7 @@ class ObjectRetriever implements CustomCacheAndLogInterface {
 
 		}
 
-		return $fileContent;
+		return $fileContent ?? null;
 	}
 
 	private function assertAuthenticatingNamespaceAndGetId() : IRI {
@@ -709,7 +709,7 @@ class ObjectRetriever implements CustomCacheAndLogInterface {
 	 * @return Node
 	 */
 	public function getAuthenticatingNamespaceObject() : ?Node {
-		return $this->getObject($this->assertAuthenticatingNamespaceAndGetId());
+		return $this->getObjectNode($this->assertAuthenticatingNamespaceAndGetId());
 	}
 
 	/**
@@ -719,7 +719,7 @@ class ObjectRetriever implements CustomCacheAndLogInterface {
 	 * @return Node
 	 */
 	public function getAuthenticatingNamespaceObjectNode() : ?Node {
-		return $this->getObject($this->assertAuthenticatingNamespaceAndGetId());
+		return $this->getObjectNode($this->assertAuthenticatingNamespaceAndGetId());
 	}
 
 	/**