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Content-Range Headers and Cloudflare Caching

Problem Discovery

Video files were not being cached by Cloudflare despite having proper Cache-Control headers set. Investigation revealed malformed Content-Range headers were preventing Cloudflare from caching the responses.

Root Cause

Apache configuration contained custom logic that attempted to manually set Content-Range headers for non-range requests:

# BROKEN CODE (removed)
Header set Accept-Ranges "bytes"
RewriteEngine On
RewriteCond %{HTTP:Range} !(^bytes=.*)
RewriteRule .* - [E=norange:1]
Header set Content-Range "bytes 0-%{CONTENT_LENGTH}e/%{CONTENT_LENGTH}e" env=norange

The Issue

  1. Malformed header values: %{CONTENT_LENGTH}e wasn’t being populated, resulting in: 
    Content-Range: bytes 0-(null)/(null)

  2. HTTP spec violation: Content-Range headers should only appear in 206 Partial Content responses (range requests), not in 200 OK responses (full file downloads)

  3. Cloudflare rejection: Cloudflare refuses to cache responses with malformed or invalid headers

Example of the Problem

Before Fix (Broken)

Response headers for full file request:

HTTP/1.1 200 OK
Content-Length: 537519808
Content-Range: bytes 0-(null)/(null)
Cache-Control: public, max-age=604800, immutable
cf-cache-status: MISS

The (null) values indicate the variable substitution failed, creating an invalid header.

After Fix (Working)

Response headers for full file request:

HTTP/1.1 200 OK
Content-Length: 347843014
Cache-Control: public, max-age=604800, immutable
cf-cache-status: HIT

No Content-Range header present (correct behavior for full file downloads).

Response headers for range request:

HTTP/1.1 206 Partial Content
Content-Range: bytes 131072-347974085/347974086
Content-Length: 347843014
Cache-Control: public, max-age=604800, immutable
cf-cache-status: HIT

Apache automatically generates proper Content-Range header with real byte positions.

The Fix

Removed the problematic rewrite rules from /home/sodo/scripts/gighive/ansible/roles/docker/templates/apache2.conf.j2:

# CORRECT CONFIGURATION
<FilesMatch "\.(mp4|mov|au|mp3|wav|aac)$">
    Header set Access-Control-Allow-Origin "*"
    Header set Access-Control-Allow-Headers "Range"
    Header set Access-Control-Expose-Headers "Content-Length, Content-Range"
</FilesMatch>

Why This Works

  1. Apache’s built-in range support: Apache automatically handles range requests without manual configuration
  2. HTTP spec compliant: Full file responses (200 OK) don’t include Content-Range headers
  3. Valid headers only: Cloudflare can now cache responses with proper headers
  4. CORS preserved: Cross-origin headers remain for browser playback

Cloudflare Caching Limits

Testing revealed an additional constraint: Cloudflare Free plan has a 512 MB file size limit for caching.

Test Results

File Size Content-Range Header cf-cache-status Cacheable
348 MB bytes 131072-347974085/347974086 HIT ✅ Yes
503 MB bytes 0-503586071/503586072 HIT ✅ Yes
537 MB bytes 71368704-537519807/537519808 MISS ❌ No (over limit)

Cloudflare Plan Limits

Plan File Size Limit Cost
Free 512 MB $0
Pro 5 GB $20/month
Business 5 GB $200/month
Enterprise Custom Custom pricing

Options Going Forward

Pros:

Cons:

Best for: Most users with typical video file sizes

Option 2: Trim Large Files

Pros:

Cons:

Example:

# Trim video to get under 512 MB
ffmpeg -i large_video.mp4 -ss 00:01:00 -to 00:55:00 -c copy trimmed_video.mp4

Best for: Users with only a few oversized files

Option 3: Upgrade to Cloudflare Pro

Pros:

Cons:

Best for: Professional deployments, high-traffic sites

Option 4: Convert to HLS Streaming

Pros:

Cons:

Example structure:

video.m3u8           # Playlist file
segment_001.ts       # 5 MB segment (cached)
segment_002.ts       # 5 MB segment (cached)
segment_003.ts       # 5 MB segment (cached)
...

Best for: Large video libraries, professional streaming applications

Option 5: Hybrid Approach

Pros:

Strategy:

Best for: Users wanting to optimize without major changes

Implementation Status

Technical Details

How Apache Handles Range Requests

Apache’s mod_headers and core functionality automatically:

  1. Advertises range support: Sends Accept-Ranges: bytes header
  2. Processes Range headers: Detects Range: bytes=X-Y in requests
  3. Generates proper responses:
    • 200 OK for full file (no Content-Range)
    • 206 Partial Content for ranges (with proper Content-Range)
  4. Handles multiple ranges: Supports complex range specifications

No manual configuration needed beyond CORS headers.

Why the Original Code Was Wrong

The removed code attempted to:

This was likely:

References