fix: Use files etag for cache busting of preview images

Signed-off-by: Ferdinand Thiessen <opensource@fthiessen.de>

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'),

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