From eaa8d0eedbb143b195502b5bb93b4429bcb965a3 Mon Sep 17 00:00:00 2001
From: Ferdinand Thiessen <opensource@fthiessen.de>
Date: Tue, 3 Oct 2023 00:53:09 +0200
Subject: [PATCH] fix: Use files etag for cache busting of preview images

Signed-off-by: Ferdinand Thiessen <opensource@fthiessen.de>
---
 lib/composables/preview.spec.ts | 12 ++++++++++++
 lib/composables/preview.ts      |  3 +++
 2 files changed, 15 insertions(+)

diff --git a/lib/composables/preview.spec.ts b/lib/composables/preview.spec.ts
index a8a110238..85ce96dfb 100644
--- a/lib/composables/preview.spec.ts
+++ b/lib/composables/preview.spec.ts
@@ -67,6 +67,18 @@ describe('preview composable', () => {
 			expect(wrapper.text()).toMatch('/core/preview?fileId=2')
 		})
 
+		it('uses etag for cache busting', () => {
+			const previewNode = new File({
+				...createData('tst.txt', 'text/plain'),
+				attributes: {
+					etag: 'the-etag',
+				},
+			})
+
+			const { previewURL } = usePreviewURL(previewNode)
+			expect(previewURL.value?.searchParams.get('c')).toBe('the-etag')
+		})
+
 		it('uses Nodes previewUrl if available', () => {
 			const previewNode = new File({
 				...createData('text.txt', 'text/plain'),
diff --git a/lib/composables/preview.ts b/lib/composables/preview.ts
index 90c69cb61..dba8d6202 100644
--- a/lib/composables/preview.ts
+++ b/lib/composables/preview.ts
@@ -73,6 +73,9 @@ export function getPreviewURL(node: Node, options: PreviewOptions = {}) {
 
 		// Handle cropping
 		url.searchParams.set('a', options.cropPreview === true ? '0' : '1')
+
+		// cache busting
+		url.searchParams.set('c', `${node.attributes.etag}`)
 		return url
 	} catch (e) {
 		return null