Improve overall preview loading

This PR improve on the logic to display previews:

1. Append the etag of the file to the file request. This ensure that old cache will not be used if the image is updated
2. Listen to 'files:file:updated' to refetch the file's info and have the new etag
3. Distinguish onload and on error events of the small and large previews to have a finer rendering conditions. Mostly not rendering both previews if the larger one is loaded.
4. Do not delay rendering of files to make the UI snappier

Signed-off-by: Louis Chemineau <louis@chmn.me>
Signed-off-by: nextcloud-command <nextcloud-command@users.noreply.github.com>

js/photos-src_mixins_AbortControllerMixin_js-src_mixins_FilesSelectionMixin_js-src_components_File_vue--80ca54.js.LICENSE.txt

@@ -41,3 +41,25 @@
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  *
  */
+
+/**
+ * @copyright Copyright (c) 2023 Louis Chemineau <louis@chmn.me>
+ *
+ * @author Louis Chemineau <louis@chmn.me>
+ *
+ * @license AGPL-3.0-or-later
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */

src/components/File.vue

@@ -33,27 +33,27 @@
 			<div class="file__images">
 				<VideoIcon v-if="file.mime.includes('video')" class="video-icon" :size="64" />
 
-				<img v-if="visibility !== 'none' && canLoad && !error"
+				<img v-if="visibility !== 'none' && canLoad && !errorNear && !loadedVisible"
 					ref="imgNear"
 					:key="`${file.basename}-near`"
 					:src="srcNear"
 					:alt="file.basename"
 					:aria-describedby="ariaDescription"
-					@load="onLoad"
-					@error="onError">
+					@load="onLoadNear"
+					@error="onErrorNear">
 
-				<img v-if="visibility === 'visible' && canLoad && !error"
+				<img v-if="(visibility === 'visible' || (loadedVisible && visibility === 'near')) && canLoad && !errorVisible"
 					ref="imgVisible"
 					:key="`${file.basename}-visible`"
 					:src="srcVisible"
 					:alt="file.basename"
 					:aria-describedby="ariaDescription"
-					@load="onLoad"
-					@error="onError">
+					@load="onLoadVisible"
+					@error="onErrorVisible">
 			</div>
 
 			<!-- image description -->
-			<p :id="ariaDescription" class="file__hidden-description" :class="{show: error}">{{ file.basename }}</p>
+			<p :id="ariaDescription" class="file__hidden-description" :class="{show: errorNear && errorVisible}">{{ file.basename }}</p>
 		</a>
 
 		<NcCheckboxRadioSwitch v-if="allowSelection"
@@ -111,8 +111,10 @@ export default {
 
 	data() {
 		return {
-			loaded: false,
-			error: false,
+			loadedNear: false,
+			loadedVisible: false,
+			errorNear: false,
+			errorVisible: false,
 			canLoad: false,
 			semaphoreSymbol: null,
 			isDestroyed: false,
@@ -146,25 +148,24 @@ export default {
 		},
 	},
 
-	mounted() {
-		// Don't render the component right away as it is useless if the user is only scrolling
-		setTimeout(async () => {
-			this.semaphoreSymbol = await this.semaphore.acquire(() => {
-				switch (this.visibility) {
-				case 'visible':
-					return 1
-				case 'near':
-					return 2
-				default:
-					return 3
-				}
-			}, this.file.fileid)
-
-			this.canLoad = true
-			if (this.visibility === 'none' || this.isDestroyed) {
-				this.releaseSemaphore()
+	async mounted() {
+		this.semaphoreSymbol = await this.semaphore.acquire(() => {
+			switch (this.visibility) {
+			case 'visible':
+				return 1
+			case 'near':
+				return 2
+			default:
+				return 3
 			}
-		}, 250)
+		}, this.file.fileid)
+
+		if (this.visibility === 'none' || this.isDestroyed) {
+			this.releaseSemaphore()
+			return
+		}
+
+		this.canLoad = true
 	},
 
 	beforeDestroy() {
@@ -185,14 +186,25 @@ export default {
 			this.$emit('click', this.file.fileid)
 		},
 
-		/** When the image is fully loaded by browser we remove the placeholder */
-		onLoad() {
-			this.loaded = true
+		/** When the 'near' image is fully loaded by browser we release semaphore */
+		onLoadNear() {
+			this.loadedNear = true
 			this.releaseSemaphore()
 		},
 
-		onError() {
-			this.error = true
+		/** When the 'visible' image is fully loaded by browser we release semaphore */
+		onLoadVisible() {
+			this.loadedVisible = true
+			this.releaseSemaphore()
+		},
+
+		onErrorNear() {
+			this.errorNear = true
+			this.releaseSemaphore()
+		},
+
+		onErrorVisible() {
+			this.errorVisible = true
 			this.releaseSemaphore()
 		},
 
@@ -203,11 +215,10 @@ export default {
 		getItemURL(size) {
 			const token = this.$route.params.token
 			if (token) {
-				return generateUrl(`/apps/photos/api/v1/publicPreview/${this.file.fileid}?x=${size}&y=${size}&token=${token}`)
+				return generateUrl(`/apps/photos/api/v1/publicPreview/${this.file.fileid}?etag=${this.decodedEtag}&x=${size}&y=${size}&token=${token}`)
 			} else {
-				return generateUrl(`/apps/photos/api/v1/preview/${this.file.fileid}?x=${size}&y=${size}`)
+				return generateUrl(`/apps/photos/api/v1/preview/${this.file.fileid}?etag=${this.decodedEtag}&x=${size}&y=${size}`)
 			}
-
 		},
 
 		releaseSemaphore() {

src/components/FilesListViewer.vue

@@ -56,13 +56,15 @@
 	</div>
 </template>
 <script>
-import { mapGetters } from 'vuex'
+import { mapActions, mapGetters } from 'vuex'
 
 import PackageVariant from 'vue-material-design-icons/PackageVariant'
 
 import { NcEmptyContent, NcLoadingIcon } from '@nextcloud/vue'
+import { subscribe, unsubscribe } from '@nextcloud/event-bus'
 
 import TiledLayout from '../components/TiledLayout/TiledLayout.vue'
+import { fetchFile } from '../services/fileFetcher.js'
 import VirtualScrolling from '../components/VirtualScrolling.vue'
 import EmptyBox from '../assets/Illustrations/empty.svg'
 
@@ -222,7 +224,19 @@ export default {
 		},
 	},
 
+	mounted() {
+		subscribe('files:file:updated', this.handleFileUpdated)
+	},
+
+	destroyed() {
+		unsubscribe('files:file:updated', this.handleFileUpdated)
+	},
+
 	methods: {
+		...mapActions([
+			'appendFiles',
+		]),
+
 		// Ask the parent for more content.
 		needContent() {
 			this.$emit('need-content')
@@ -237,6 +251,15 @@ export default {
 				ratio: file.fileMetadataSizeParsed.width / file.fileMetadataSizeParsed.height,
 			}
 		},
+
+		/**
+		 * @param {object} data
+		 * @param {string} data.fileid - The file id of the updated file.
+		 */
+		async handleFileUpdated({ fileid }) {
+			const fetchedFile = await fetchFile(this.files[fileid].filename)
+			this.appendFiles([fetchedFile])
+		},
 	},
 }
 </script>

src/services/fileFetcher.js

@@ -0,0 +1,73 @@
+/**
+ * @copyright Copyright (c) 2023 Louis Chemineau <louis@chmn.me>
+ *
+ * @author Louis Chemineau <louis@chmn.me>
+ *
+ * @license AGPL-3.0-or-later
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+import { genFileInfo } from '../utils/fileUtils.js'
+import defaultClient from './DavClient.js'
+
+/**
+ * @param {string[]} extraProps - Extra properties to add to the DAV request.
+ * @return {string}
+ */
+function getCollectionFilesDavRequest(extraProps = []) {
+	return `<?xml version="1.0"?>
+			<d:propfind xmlns:d="DAV:"
+				xmlns:oc="http://owncloud.org/ns"
+				xmlns:nc="http://nextcloud.org/ns"
+				xmlns:ocs="http://open-collaboration-services.org/ns">
+				<d:prop>
+					<d:getcontentlength />
+					<d:getcontenttype />
+					<d:getetag />
+					<d:getlastmodified />
+					<d:resourcetype />
+					<nc:file-metadata-size />
+					<nc:has-preview />
+					<oc:favorite />
+					<oc:fileid />
+					<oc:permissions />
+					${extraProps.join('')}
+				</d:prop>
+			</d:propfind>`
+}
+
+/**
+ * @param {string} fileName - The full file's name
+ * @param {import('webdav').StatOptions} options - Options to forward to the webdav client.
+ * @return {Promise<object>}
+ */
+export async function fetchFile(fileName, options = {}) {
+	try {
+		const response = await defaultClient.stat(fileName, {
+			data: getCollectionFilesDavRequest(),
+			details: true,
+			...options,
+		})
+
+		return genFileInfo(response.data)
+	} catch (error) {
+		if (error.code === 'ERR_CANCELED') {
+			return null
+		}
+
+		throw error
+	}
+}

src/utils/fileUtils.js

@@ -122,7 +122,7 @@ function genFileInfo(obj) {
 
 	if (fileInfo.filename) {
 		// Adding context
-		fileInfo.source = generateRemoteUrl(rootPath) + '/' + encodeFilePath(fileInfo.filename)
+		fileInfo.source = generateRemoteUrl(rootPath) + encodeFilePath(fileInfo.filename)
 	}
 
 	return fileInfo