fix(Respond to Webhook Node)!: Surround HTML in iframe (#16978)

Co-authored-by: Tomi Turtiainen <10324676+tomi@users.noreply.github.com>

packages/nodes-base/nodes/RespondToWebhook/utils/binary.ts

@@ -0,0 +1,42 @@
+import { isHtmlRenderedContentType, sandboxHtmlResponse } from 'n8n-core';
+import type { IBinaryData, IDataObject, IN8nHttpResponse } from 'n8n-workflow';
+import { BINARY_ENCODING } from 'n8n-workflow';
+import type { Readable } from 'stream';
+
+const setContentLength = (responseBody: IN8nHttpResponse | Readable, headers: IDataObject) => {
+	if (Buffer.isBuffer(responseBody)) {
+		headers['content-length'] = responseBody.length;
+	} else if (typeof responseBody === 'string') {
+		headers['content-length'] = Buffer.byteLength(responseBody, 'utf8');
+	}
+};
+
+/**
+ * Returns a response body for a binary data and sets the content-type header.
+ */
+export const getBinaryResponse = (binaryData: IBinaryData, headers: IDataObject) => {
+	const contentType = headers['content-type'] as string;
+	const shouldSandboxResponseData =
+		isHtmlRenderedContentType(binaryData.mimeType) ||
+		(contentType && isHtmlRenderedContentType(contentType));
+
+	let responseBody: IN8nHttpResponse | Readable;
+
+	if (binaryData.id) {
+		responseBody = shouldSandboxResponseData
+			? sandboxHtmlResponse(binaryData.data)
+			: { binaryData };
+	} else {
+		const responseBuffer = Buffer.from(binaryData.data, BINARY_ENCODING);
+
+		responseBody = shouldSandboxResponseData
+			? sandboxHtmlResponse(responseBuffer.toString())
+			: responseBuffer;
+
+		setContentLength(responseBody, headers);
+	}
+
+	headers['content-type'] ??= binaryData.mimeType;
+
+	return responseBody;
+};