feat: generate thumbnail from client is not found on server

- supported thumbnail filetype: image, pdf, video - add play character if video's thumbnail is loaded
2026-04-29 00:06:44 +02:00
parent c6b1b14444
commit f6cd18e5e9
9 changed files with 269 additions and 25 deletions
@@ -0,0 +1,181 @@
+import { getCsrfHeaders } from '../core/csrf.js';
+
+/** @type {typeof import('../vendors/pdf.min.d.ts') | null} */
+let _pdfjsLib = null;
+
+/**
+ * Lazy-loads pdf.min.mjs on first use via dynamic import so it is never
+ * bundled into the IIFE (it uses top-level await which breaks IIFE wrapping).
+ * @returns {Promise<typeof import('../vendors/pdf.min.d.ts')>}
+ */
+async function getPdfjsLib() {
+    if (_pdfjsLib) return _pdfjsLib;
+    _pdfjsLib = await import('/js/vendors/pdf.min.mjs');
+    _pdfjsLib.GlobalWorkerOptions.workerSrc = '/js/vendors/pdf.worker.min.mjs';
+    return _pdfjsLib;
+}
+
+export const thumbnail = {
+    SUPPORTED_CLASS: ['image-icon', 'pdf-icon', 'video-icon'],
+    /**
+     *
+     * @param {String} iconSpecialClass
+     * @returns {boolean}
+     */
+    canHandle(iconSpecialClass) {
+        return this.SUPPORTED_CLASS.includes(iconSpecialClass);
+    },
+
+    // TODO: use these informations from server ?
+    SIZES: {
+        icon: { width: 150, height: 150 },
+        preview: { width: 300, height: 300 },
+        large: { width: 900, height: 800 }
+    },
+
+    // note: server moved to jpeg q=80 for images
+    // FORMAT: 'image/webp',
+    // QUALITY: 0.85,
+    FORMAT: 'image/jpeg',
+    QUALITY: 0.8,
+
+    /**
+     * @typedef {Object} Size
+     * @property {number} width
+     * @property {number} height
+     */
+
+    /**
+     *
+     * @param {number} srcWidth
+     * @param {number} srcHeight
+     * @param {number} targetWidth
+     * @param {number} targetHeight
+     * @returns {Size}
+     */
+    computeSize(srcWidth, srcHeight, targetWidth, targetHeight) {
+        const srcRatio = srcWidth / srcHeight;
+        const targetRatio = targetWidth / targetHeight;
+        if (srcRatio > targetRatio) {
+            return { width: targetWidth, height: Math.round(targetWidth / srcRatio) };
+        } else {
+            return { width: Math.round(targetHeight * srcRatio), height: targetHeight };
+        }
+    },
+
+    /**
+     *
+     * @param {ImageBitmap} bitmap
+     * @param {number} targetWidth
+     * @param {number} targetHeight
+     * @param {ImageEncodeOptions} imageEncodeOptions
+     * @returns
+     */
+    bitmapToBlob(bitmap, targetWidth, targetHeight, imageEncodeOptions) {
+        const { width, height } = this.computeSize(bitmap.width, bitmap.height, targetWidth, targetHeight);
+        const canvas = new OffscreenCanvas(width, height);
+        canvas.getContext('2d')?.drawImage(bitmap, 0, 0, width, height);
+        return canvas.convertToBlob(imageEncodeOptions);
+    },
+
+    /**
+     *
+     * @param {Blob} blob
+     * @returns
+     */
+    blobToDataUrl(blob) {
+        return new Promise((resolve, reject) => {
+            const reader = new FileReader();
+            reader.onload = () => resolve(reader.result);
+            reader.onerror = reject;
+            reader.readAsDataURL(blob);
+        });
+    },
+
+    /**
+     *
+     * @param {Object} file
+     * @param {string} source
+     * @returns
+     */
+    async sourceToBitmap(file, source) {
+        switch (file.icon_special_class) {
+            case 'image-icon': {
+                const response = await fetch(source);
+                if (!response.ok) throw new Error(`failed to fetch: ${response.status}`);
+                const blob = await response.blob();
+                return createImageBitmap(blob);
+            }
+
+            case 'pdf-icon': {
+                const pdfjsLib = await getPdfjsLib();
+                const pdf = await pdfjsLib.getDocument(source).promise;
+                const page = await pdf.getPage(1);
+                const viewport = page.getViewport({ scale: 1 });
+                const canvas = document.createElement('canvas');
+                canvas.width = viewport.width;
+                canvas.height = viewport.height;
+                await page.render({ canvasContext: canvas.getContext('2d'), viewport }).promise;
+                return createImageBitmap(canvas);
+            }
+
+            case 'video-icon': {
+                return new Promise((resolve, reject) => {
+                    const video = document.createElement('video');
+                    video.src = source;
+                    video.muted = true;
+                    video.preload = 'metadata';
+                    video.onloadedmetadata = () => {
+                        // seek to 1/3 of video to take snapshot
+                        video.currentTime = video.duration / 3;
+                    };
+                    video.onseeked = async () => {
+                        const bitmap = await createImageBitmap(video);
+                        video.pause();
+                        video.removeAttribute('src'); // hack to close network connection
+                        video.load();
+                        resolve(bitmap);
+                    };
+                    video.onerror = reject;
+                });
+            }
+
+            default:
+                throw new Error(`unknown type: ${file.icon_special_class} for file ${file.name}`);
+        }
+    },
+
+    /**
+     * generateThumbnail and update image
+     *
+     * @param {Object} file the source of the image
+     * @param {(dataURL: string) => void} [onIconGenerated] the callback once thumbnail is generated
+     */
+    async generate(file, onIconGenerated) {
+        const source = `${window.location.origin}/api/files/${file.id}`;
+
+        const bitmap = await this.sourceToBitmap(file, source);
+
+        const [iconBlob, previewBlob, largeBlob] = await Promise.all(
+            Object.values(this.SIZES).map(({ width, height }) => this.bitmapToBlob(bitmap, width, height, { type: this.FORMAT, quality: this.QUALITY }))
+        );
+
+        if (onIconGenerated) {
+            onIconGenerated(await this.blobToDataUrl(iconBlob));
+        }
+
+        await Promise.all(
+            [
+                ['icon', iconBlob],
+                ['preview', previewBlob],
+                ['large', largeBlob]
+            ].map(([size, blob]) =>
+                fetch(`${window.location.origin}/api/files/${file.id}/thumbnail/${size}`, {
+                    method: 'PUT',
+                    headers: { ...getCsrfHeaders(), 'Content-Type': this.FORMAT },
+                    body: blob
+                }).then((r) => console.log(`uploaded ${size} thumbnail of ${file.name}: ${r.status}`))
+            )
+        );
+    }
+};