Do not send a body for "No content", "Not modified" and others

Signed-off-by: Joas Schilling <coding@schilljs.com>

lib/private/AppFramework/OCS/BaseResponse.php

@@ -22,6 +22,7 @@
  */
 namespace OC\AppFramework\OCS;
 
+use OCP\AppFramework\Http;
 use OCP\AppFramework\Http\DataResponse;
 use OCP\AppFramework\Http\EmptyContentSecurityPolicy;
 use OCP\AppFramework\Http\Response;
@@ -85,9 +86,60 @@ abstract class BaseResponse extends Response   {
 	 * @param string[] $meta
 	 * @return string
 	 */
-	protected function renderResult($meta) {
-		// TODO rewrite functions
-		return \OC_API::renderResult($this->format, $meta, $this->data);
+	protected function renderResult(array $meta): string {
+		$status = $this->getStatus();
+		if ($status === Http::STATUS_NO_CONTENT ||
+			$status === Http::STATUS_NOT_MODIFIED ||
+			($status >= 100 && $status <= 199)) {
+			// Those status codes are not supposed to have a body:
+			// https://stackoverflow.com/q/8628725
+			return '';
+		}
+
+		$response = [
+			'ocs' => [
+				'meta' => $meta,
+				'data' => $this->data,
+			],
+		];
+
+		if ($this->format === 'json') {
+			return json_encode($response, JSON_HEX_TAG);
+		}
+
+		$writer = new \XMLWriter();
+		$writer->openMemory();
+		$writer->setIndent(true);
+		$writer->startDocument();
+		$this->toXML($response, $writer);
+		$writer->endDocument();
+		return $writer->outputMemory(true);
+
+	}
+
+	/**
+	 * @param array $array
+	 * @param \XMLWriter $writer
+	 */
+	protected function toXML(array $array, \XMLWriter $writer) {
+		foreach ($array as $k => $v) {
+			if ($k[0] === '@') {
+				$writer->writeAttribute(substr($k, 1), $v);
+				continue;
+			}
+
+			if (\is_numeric($k)) {
+				$k = 'element';
+			}
+
+			if (\is_array($v)) {
+				$writer->startElement($k);
+				$this->toXML($v, $writer);
+				$writer->endElement();
+			} else {
+				$writer->writeElement($k, $v);
+			}
+		}
 	}
 
 	public function getOCSStatus() {