fix-jdownloader-websocket

[folklor33]

Fix JDownloader websocket configuration for proper VNC display

• I have read the contributing guideline and understand that I have made the correct modifications

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Description

Fixed JDownloader websocket configuration to properly handle VNC display connections. The current configuration causes websocket connection failures with "invalid URL prefix" errors, preventing the VNC interface from loading.

Added specific websocket location blocks with proper headers and timeout configurations to ensure reliable VNC connections through the reverse proxy.

Benefits of this PR and context

• Fixes VNC display issues: Users can now properly access the JDownloader GUI through the web interface
• Resolves websocket errors: Eliminates "invalid URL prefix in '://:/websockify'" errors in nginx logs
• Improves user experience: No more blank screens or connection timeouts when accessing JDownloader
• Maintains backward compatibility: Existing configurations continue to work while adding enhanced websocket support

This addresses a common issue where users experience blank screens or connection failures when trying to access JDownloader through the reverse proxy, particularly affecting the VNC/web interface functionality.

How Has This Been Tested?

• Environment: Docker Swag + JDownloader 2 container (jlesage/jdownloader-2)
• Network: Custom Docker bridge network with Authelia authentication
• Testing steps:
  1. Applied the original configuration - confirmed VNC display failure with websocket errors
  2. Applied the fixed configuration - confirmed working VNC display and successful websocket connections
  3. Tested with and without Authelia authentication - both scenarios work correctly
  4. Verified nginx logs show successful websocket upgrades instead of "invalid URL prefix" errors
  5. Tested multiple browser connections and reconnections - all stable

Source / References

• Issue identified through nginx error logs showing websocket connection failures
• Solution developed based on proper websocket proxy configuration patterns
• Tested in production environment with successful results

[Roxedus]

does #774 not do it?

[folklor33]

does #774 not do it?

yoooups...