feat(preview): add file preview page with metadata and styling

Implement a rich file preview interface to allow users to view file contents directly in the browser. Changes include: - Exposing raw file size (`SizeBytes`) in the download handler's file view. - Adding comprehensive CSS styling for the preview layout and cards. - Integrating Prism.js for syntax highlighting of code files. - Updating Content Security Policy (CSP) headers to permit inline styles and frame sources required by the preview components. - Adding unit tests to ensure preview metadata attributes are correctly rendered on the download page.
2026-06-03 14:28:50 +03:00
parent e17c5e92a7
commit 3a0dd04e61
12 changed files with 1893 additions and 36 deletions
--- a/backend/templates/layouts/base.html
+++ b/backend/templates/layouts/base.html
@@ -60,6 +60,7 @@
  <script defer src="/static/js/30-token-copy.js?version={{.AppVersion}}"></script>
  <script defer src="/static/js/35-pagination.js?version={{.AppVersion}}"></script>
  <script defer src="/static/js/40-upload.js?version={{.AppVersion}}"></script>
+  <script defer src="/static/js/45-preview.js?version={{.AppVersion}}"></script>
 </head>
 <body class="dark">
  <a class="skip-link" href="#main">Skip to content</a>
--- a/backend/templates/pages/preview.html
+++ b/backend/templates/pages/preview.html
@@ -1,8 +1,8 @@
 {{define "preview.html"}}{{template "base" .}}{{end}}

 {{define "content"}}
-<section class="download-view" aria-labelledby="preview-title">
-  <div class="card download-card">
+<section class="download-view preview-view" aria-labelledby="preview-title">
+  <div class="card download-card preview-card">
    <div class="card-content">
      {{if .Data.Locked}}
        <div class="file-emblem" aria-hidden="true">
@@ -12,23 +12,65 @@
        <p class="download-subtitle">Unlock the box before viewing this file.</p>
        <a class="button button-primary button-wide" href="/d/{{.Data.Box.ID}}">Unlock box</a>
      {{else}}
-        <div class="preview-stage">
-          {{if eq .Data.File.PreviewKind "image"}}
-            <img src="{{.Data.DownloadURL}}?inline=1" alt="{{.Data.File.Name}}">
-          {{else if eq .Data.File.PreviewKind "video"}}
-            <video src="{{.Data.DownloadURL}}?inline=1" poster="{{.Data.File.ThumbnailURL}}" controls preload="metadata"></video>
-          {{else if eq .Data.File.PreviewKind "audio"}}
-            <audio src="{{.Data.DownloadURL}}?inline=1" controls preload="metadata"></audio>
-          {{else}}
-            <img src="{{.Data.File.ThumbnailURL}}" alt="">
-          {{end}}
+        <header class="preview-header">
+          <div class="preview-title-group">
+            <h1 id="preview-title" class="file-name" title="{{.Data.File.Name}}">{{.Data.File.Name}}</h1>
+            <p class="download-subtitle">{{.Data.File.Size}} · {{.Data.File.ContentType}}</p>
+          </div>
+          <a class="button button-primary" href="{{.Data.DownloadURL}}">
+            <svg viewBox="0 0 24 24" role="img" focusable="false" aria-hidden="true"><path d="M12 3v12m0 0 4-4m-4 4-4-4M5 21h14" /></svg>
+            Download
+          </a>
+        </header>
+
+        <div class="preview-window" data-preview-kind="{{.Data.File.PreviewKind}}" data-file-name="{{.Data.File.Name}}" data-content-type="{{.Data.File.ContentType}}" data-size-bytes="{{.Data.File.SizeBytes}}" data-source-url="{{.Data.DownloadURL}}?inline=1" data-download-url="{{.Data.DownloadURL}}" data-icon-url="{{.Data.File.IconURL}}" data-file-size="{{.Data.File.Size}}">
+          <div class="preview-window-titlebar">
+            <div>
+              <strong data-preview-mode-label>Preview</strong>
+              <span>{{.Data.File.ContentType}}</span>
+            </div>
+            <div class="preview-window-tools">
+              <button class="preview-fullscreen-button" type="button" data-render-fullscreen hidden>Full Screen</button>
+              <div class="preview-window-actions" aria-hidden="true"><span></span><span></span><span></span></div>
+            </div>
+          </div>
+          <div class="preview-tabs" data-preview-tabs></div>
+          <div class="preview-stage">
+            <div class="default-preview" data-default-preview hidden>
+              <img src="{{.Data.File.IconURL}}" alt="" loading="lazy">
+              <div>
+                <strong title="{{.Data.File.Name}}">{{.Data.File.Name}}</strong>
+                <span>{{.Data.File.Size}} · {{.Data.File.ContentType}}</span>
+              </div>
+              <a class="button button-primary" href="{{.Data.DownloadURL}}">
+                <svg viewBox="0 0 24 24" role="img" focusable="false" aria-hidden="true"><path d="M12 3v12m0 0 4-4m-4 4-4-4M5 21h14" /></svg>
+                Download
+              </a>
+            </div>
+            <img class="native-preview native-image-preview" data-image-preview src="{{.Data.DownloadURL}}?inline=1" alt="{{.Data.File.Name}}" hidden>
+            <video class="native-preview native-video-preview" data-video-preview src="{{.Data.DownloadURL}}?inline=1" poster="{{.Data.File.ThumbnailURL}}" controls preload="metadata" hidden></video>
+            <audio class="native-preview native-audio-preview" data-browser-audio-preview src="{{.Data.DownloadURL}}?inline=1" controls preload="metadata" hidden></audio>
+            <div class="code-preview raw-code-preview" data-raw-preview hidden>
+              <pre><code data-raw-output></code></pre>
+            </div>
+            <div class="code-preview prism-code-preview" data-code-preview hidden>
+              <pre class="line-numbers"><code data-code-output></code></pre>
+            </div>
+            <iframe class="render-preview" data-render-preview title="Rendered preview of {{.Data.File.Name}}" sandbox hidden></iframe>
+            <div class="large-preview-gate" data-large-preview-gate hidden>
+              <strong>Large preview</strong>
+              <p>This file is larger than 500 KB. Loading this preview may be slow on some devices.</p>
+              <div>
+                <button class="button button-primary" type="button" data-large-preview-confirm>Load anyway</button>
+                <button class="button button-outline" type="button" data-large-preview-cancel>Cancel</button>
+              </div>
+            </div>
+            <div class="preview-placeholder" data-preview-placeholder hidden>
+              <img src="{{.Data.File.IconURL}}" alt="">
+              <p>Preparing preview...</p>
+            </div>
+          </div>
        </div>
-        <h1 id="preview-title" class="file-name" title="{{.Data.File.Name}}">{{.Data.File.Name}}</h1>
-        <p class="download-subtitle">{{.Data.File.Size}} · {{.Data.File.ContentType}}</p>
-        <a class="button button-primary button-wide" href="{{.Data.DownloadURL}}">
-          <svg viewBox="0 0 24 24" role="img" focusable="false" aria-hidden="true"><path d="M12 3v12m0 0 4-4m-4 4-4-4M5 21h14" /></svg>
-          Download file
-        </a>
      {{end}}
    </div>
  </div>