更新 README 文档，新增 WebDAV 桥接服务的功能介绍、使用方法及部署配置说明

README_en.md

@@ -102,7 +102,110 @@ Provides detailed deployment documentation, feature docs, development plans, upd
 
 </details>
 
-# 4. Tips
+# 4. WebDAV Bridge Service
+
+This project provides a powerful **WebDAV Bridge Cloudflare Worker** that allows you to access and manage hosted files through the standard WebDAV protocol.
+
+## 4.1 Features
+
+- 🔒 **Authentication**: Supports Basic Auth authentication with username/password
+- 📁 **Directory Browsing**: Complete directory structure display, supports both HTML pages and WebDAV clients
+- 📤 **File Upload**: Upload files to specified directories using PUT method
+- 🗑️ **File Deletion**: Support for deleting individual files or entire folders
+- 📥 **File Download**: Direct file downloads with automatic proxy to upstream storage
+- 🌐 **CORS Support**: Built-in CORS support ensuring proper web client access
+
+## 4.2 Supported WebDAV Methods
+
+| Method | Function | Description |
+|--------|----------|-------------|
+| `PROPFIND` | List directory contents | Get file and folder lists, supports WebDAV clients |
+| `GET` | Download file/browse directory | File downloads or HTML directory browsing pages |
+| `PUT` | Upload file | Upload files to specified paths and folders |
+| `DELETE` | Delete file/folder | Support for deleting individual files or entire directories |
+| `OPTIONS` | Protocol detection | Returns supported WebDAV methods and features |
+| `MKCOL` | Create directory | Create new folders (automatically supported) |
+
+## 4.3 Deployment Configuration
+
+### 4.3.1 Environment Variables
+
+Set the following environment variables in your Cloudflare Worker:
+
+```bash
+# WebDAV authentication credentials
+AUTH_USER=your_username          # WebDAV login username
+AUTH_PASS=your_password          # WebDAV login password
+
+# Upstream API configuration
+UPSTREAM_HOST=your-imgbed.domain.com  # Your image bed domain
+API_TOKEN=your_api_token         # API access token
+```
+
+### 4.3.2 Custom Domain Binding (Recommended)
+
+For a better user experience, it's highly recommended to bind a custom domain to your WebDAV Worker:
+
+1. **Prepare Domain**: Ensure you have an available domain that is hosted on Cloudflare
+2. **Add Custom Route**:
+   - Go to Cloudflare Workers console
+   - Select your WebDAV Worker
+   - Click the `Triggers` tab
+   - Click `Add Custom Domain`
+   - Enter your subdomain, e.g.: `webdav.yourdomain.com`
+   - Click `Add Domain`
+
+3. **SSL Certificate**: Cloudflare will automatically provide a free SSL certificate for your custom domain
+
+**Advantages of Using Custom Domain**:
+- 🌟 **Better Compatibility**: Avoid limitations some WebDAV clients have with `.workers.dev` domains
+- 🔒 **Enhanced Security**: Custom domains are generally more trusted by clients
+- 📱 **Mobile Friendly**: iOS/Android devices have better support for custom domains
+- 🎯 **Brand Consistency**: Use a unified domain system with your image hosting service
+
+## 4.4 Usage
+
+### Browser Access
+Access the Worker address directly in your browser and enter authentication credentials to browse file directories:
+```
+# Using custom domain (recommended)
+https://webdav.yourdomain.com/
+
+# Or using default Worker domain
+https://your-webdav-worker.your-subdomain.workers.dev/
+```
+
+### WebDAV Clients
+You can use any WebDAV-compatible client to connect:
+
+**Windows File Explorer**:
+1. Open "This PC"
+2. Right-click and select "Add a network location"
+3. Enter the WebDAV Worker address
+4. Enter username and password
+
+**macOS Finder**:
+1. Press `Cmd+K` in Finder
+2. Enter WebDAV address (custom domain recommended):
+   - `https://webdav.yourdomain.com` or
+   - `https://your-webdav-worker.your-subdomain.workers.dev`
+3. Enter authentication credentials
+
+**Third-party Clients**:
+- File managers like Cyberduck, WinSCP, FileZilla Pro
+- Mobile: FE File Explorer, Documents by Readdle, etc.
+
+## 4.5 Key Features
+
+- **Smart Path Handling**: Automatic path processing with support for Chinese characters and special characters
+- **Paginated Loading**: Large directories are automatically paginated for improved performance
+- **Error Handling**: Comprehensive error handling with user-friendly error messages
+- **Cache Optimization**: Proper browser caching utilization for improved access speed
+- **Secure & Reliable**: Based on Cloudflare Worker edge computing with global acceleration
+
+Through WebDAV Bridge, you can manage hosted files just like using a local folder, achieving a true "cloud drive" experience!
+
+# 5. Tips
 
 - Frontend is open source, see [MarSeventh/Sanyue-ImgHub](https://github.com/MarSeventh/Sanyue-ImgHub).