[ISSUE] v5.0.2 直接图片预览不显示文件名

Issue Type / 问题类型

Bug / 缺陷

kkFileView Version / kkFileView 版本

v5.0.2

Upstream commit: c4288f7e59b8d59d94a2f445ef759b657cde6543

Deployment Mode / 部署方式

Source build / Docker

Environment / 环境信息

• Linux container
• JDK 21
• Microsoft Edge / Google Chrome
• The reproduced build is pinned to the upstream v5.0.2 commit. picture.ftl and viewer.min.js are unchanged from upstream.

Steps to Reproduce / 复现步骤

1. Start kkFileView v5.0.2.

2. Prepare any publicly accessible PNG image, for example:

   https://www.w3.org/Icons/w3c_home.png

3. Base64-encode and URL-encode the image URL.

4. Open:

   /onlinePreview?url=aHR0cHM6Ly93d3cudzMub3JnL0ljb25zL3czY19ob21lLnBuZw%3D%3D

5. Check the filename/title area in the Viewer.js image preview.

6. Compare the same image with kkFileView v4.3.0.

Expected Result / 期望结果

The image is displayed and the Viewer.js title shows the decoded filename, for example w3c_home.png, consistent with v4.3.0.

Actual Result / 实际结果

The image loads and the normal viewing controls work, but the filename/title is empty.

Root Cause Analysis / 原因分析

In v4.3.0, picture.ftl uses a standard image element:

<li><img src="${img}" style="display: none"></li>

Viewer.js derives the title from the DOM src property:

var src = image.src;
var alt = image.alt || getImageNameFromURL(src);

Commit 7dc0469b30a0 changed the template element and the Viewer.js selector from img to div:

<li><div src="${finalUrl}" data-original-url="${finalUrl}" style="display: none"></li>

Viewer.js can still load the image through the configured url: 'src' option and getAttribute('src'). However, HTMLDivElement has no standard src DOM property, so image.src is undefined and getImageNameFromURL(image.src) returns an empty string.

As of 2026-09-03, the master branch still uses <div src> without supplying a filename or alt value.

Suggested Fix / 建议修复方向

Before Viewer initialization, derive the filename from data-original-url and explicitly provide it to the Viewer title logic, or update the Viewer integration so title generation falls back to data-original-url / the configured URL attribute.

When a fetch proxy is enabled, the filename should be derived from data-original-url, not from a proxy URL such as getCorsFile?....

Logs & Screenshots / 日志与截图

No backend exception or browser console error is required to reproduce the issue. The image request and preview page both succeed; the failure is limited to title generation.

No screenshot is attached for now. The rendered HTML and the source comparison above reproduce the cause deterministically.

Sample File / 样例文件

Public sample: https://www.w3.org/Icons/w3c_home.png

Checklist / 提交前检查

• I searched existing issues and did not find a duplicate. / 我已搜索现有 Issue，未发现重复问题。
• I can reproduce this issue on the stated version/environment. / 我可在上述版本与环境复现该问题。
• The report contains no private deployment addresses, internal file URLs, credentials, or sensitive logs. / 本报告不包含私有部署地址、内部文件 URL、凭据或敏感日志。

ℹ️ This issue was prepared with assistance from ChatGPT Codex/GPT-5. The current client did not expose a session ID, 2026-09-03.