Fix data feed failing on Cloudflare preview - #182
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Resolves data feed failures when visiting PR preview URLs for the first time. The issue occurred because Cloudflare's edge cache was serving CORS responses without considering the requesting origin. Root Cause: Cloudflare's cache uses only the URL as the cache key by default. When different origins (pr-123, pr-184, etc.) request the same URL, they would receive the same cached response, including CORS headers meant for a different origin. This caused CORS errors when the browser rejected the mismatched Access-Control-Allow-Origin header. The Fix: Add Vary: Origin header to all CORS responses. This tells Cloudflare (and other caches) to include the Origin request header in the cache key, ensuring each origin gets its own cached response with correct CORS headers. Additional improvements: - Reduce CORS preflight cache to 10 seconds for staging/preview environments (down from 5 minutes) to allow quick recovery from any deployment issues - Production keeps 5 minute preflight cache for optimal performance This is the standard solution for caching origin-specific CORS responses.
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Resolves data feed failures when visiting PR preview URLs for the first time. The issue occurred because Cloudflare's edge cache was serving CORS responses without considering the requesting origin.
Root Cause:
Cloudflare's cache uses only the URL as the cache key by default. When different origins (pr-123, pr-184, etc.) request the same URL, they would receive the same cached response, including CORS headers meant for a different origin. This caused CORS errors when the browser rejected the mismatched Access-Control-Allow-Origin header.
The Fix:
Add Vary: Origin header to all CORS responses. This tells Cloudflare (and other caches) to include the Origin request header in the cache key, ensuring each origin gets its own cached response with correct CORS headers.
Additional improvements:
This is the standard solution for caching origin-specific CORS responses.