FreshRSS-Extensions/xExtension-ImageCamo

Image Camo Proxy Extension for FreshRSS

This extension allows FreshRSS to proxy images through a Camo server (eg. go-camo), providing secure image delivery without mixed content warnings on HTTPS sites and without running an open proxy.

Features

• Proxy HTTP and/or HTTPS images through go-camo
• Support for both Base64 and Hex URL encoding (go-camo compatible)
• Configurable scheme handling for protocol-relative URLs
• Preserves original URLs in data attributes for FreshRSS compatibility
• Supports responsive images with srcset attributes

Requirements

• A running camo server instance (eg. go-camo)
• HMAC key configured in camo server

Configuration

1. Camo Proxy URL: The base URL of your camo server (e.g., https://your-camo-instance.example.com)
2. HMAC Key: The shared secret key used to sign URLs (must match your camo server configuration)
3. URL Encoding: Choose between Base64 (recommended, shorter URLs) or Hex encoding
4. Proxy HTTP images: Enable/disable proxying of HTTP images
5. Proxy HTTPS images: Enable/disable proxying of HTTPS images (usually disabled for performance)
6. Proxy protocol-relative URLs: How to handle URLs starting with //
7. Include http:// in URL*: Whether to include the protocol scheme in the proxied URL

How it works

1. The extension intercepts image URLs in RSS feed content
2. For each image URL that matches the configured criteria:
   • Generates an HMAC-SHA1 signature using the configured key
   • Encodes both the signature and URL (Base64 or Hex)
   • Constructs a go-camo compatible URL: {camo-url}/{signature}/{encoded-url}
3. The original URLs are preserved in data attributes

Security Considerations

• Keep your HMAC key secret and secure
• Use a strong, random HMAC key

Based on

This extension is based on the xExtension-ImageProxy extension but specifically designed for go-camo compatibility.