diff --git a/apps/files_external/lib/Lib/Storage/AmazonS3.php b/apps/files_external/lib/Lib/Storage/AmazonS3.php
index 8e2a6b8ea12e3..0d1010a4cfbe9 100644
--- a/apps/files_external/lib/Lib/Storage/AmazonS3.php
+++ b/apps/files_external/lib/Lib/Storage/AmazonS3.php
@@ -43,6 +43,7 @@
 use Aws\S3\Exception\S3Exception;
 use Aws\S3\S3Client;
 use Icewind\Streams\CallbackWrapper;
+use Icewind\Streams\CountWrapper;
 use Icewind\Streams\IteratorDirectory;
 use OCP\Cache\CappedMemoryCache;
 use OC\Files\Cache\CacheEntry;
@@ -790,4 +791,24 @@ public function hasUpdated($path, $time) {
 			return true;
 		}
 	}
+
+	public function writeStream(string $path, $stream, ?int $size = null): int {
+		if ($size === null) {
+			$size = 0;
+			// track the number of bytes read from the input stream to return as the number of written bytes.
+			$stream = CountWrapper::wrap($stream, function (int $writtenSize) use (&$size) {
+				$size = $writtenSize;
+			});
+		}
+
+		if (!is_resource($stream)) {
+			throw new \InvalidArgumentException("Invalid stream provided");
+		}
+
+		$path = $this->normalizePath($path);
+		$this->writeObject($path, $stream, $this->mimeDetector->detectPath($path));
+		$this->invalidateCache($path);
+
+		return $size;
+	}
 }