Add HTTP Range header support for partial static file serving

[Copilot]

Implementation Plan for Partial Static Files (HTTP Range Support)

• Understand existing static file serving code
• Add Range header parsing logic
• Implement byte range calculation and validation
• Add Accept-Ranges header to static file responses
• Modify file streaming to support ranges with 206 status
• Handle edge cases (invalid ranges, out of bounds, etc.)
• Test with curl commands for Range requests
• Verify backward compatibility (requests without Range header)
• Address code review feedback
• Add stream error handling
• Eliminate code duplication in stream creation

Implementation Complete and Reviewed!

Features Added:

• ✅ HTTP Range support for static files (PNG, PDF, JPG, etc.)
• ✅ Three range formats supported:
  • bytes=0-999 - specific byte range
  • bytes=1000- - from byte to end of file
  • bytes=-500 - last N bytes (suffix range)
• ✅ Returns HTTP 206 Partial Content with Content-Range header
• ✅ Returns HTTP 416 Range Not Satisfiable for invalid ranges
• ✅ Accept-Ranges: bytes header on all static file responses
• ✅ Range requests only work on uncompressed files (by design)
• ✅ HEAD requests properly ignore Range headers
• ✅ Multi-range requests gracefully fall back to full file
• ✅ Stream error handling to prevent crashes
• ✅ Clean, DRY code without duplication
• ✅ Fully backward compatible with existing functionality

Testing Results:

All test scenarios passed including:

• Normal requests (200 OK)
• Valid range requests (206 Partial Content)
• Invalid ranges (416 Range Not Satisfiable)
• Suffix ranges for last N bytes
• Open-ended ranges (from byte to end)
• Out-of-bounds detection
• HEAD request handling
• Multi-range request fallback
• Stream error handling

Original prompt

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This section details on the original issue you should resolve

<issue_title>partial static files</issue_title>
<issue_description>when serving big static files, allow sending only a range specified in header</issue_description>

<agent_instructions>Give it a try and tell me if there are bigger impediments in working with this codebase.</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes partial static files #6

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[L3P3]

@copilot I dont like the code duplication after the else if (is_range_request) {. Please merge it and pass an empty object or start end object to the createReadStream like is_range_request ? {start end} : {}.

[Copilot]

@copilot I dont like the code duplication after the else if (is_range_request) {. Please merge it and pass an empty object or start end object to the createReadStream like is_range_request ? {start ...

Done! Merged the duplicate code paths using a conditional object is_range_request ? {start, end} : {}. This eliminates the duplication while maintaining the same functionality. Commit: 8f61134