Workers Fetch API can override Cache Rules

You can now programmatically override Cache Rules using the cf object in the fetch() command. This feature gives you fine-grained control over caching behavior on a per-request basis, allowing Workers to customize cache settings dynamically based on request properties, user context, or business logic.

How it works

Using the cf object in fetch(), you can override specific Cache Rules settings by:

1. Setting custom cache options: Pass cache properties in the cf object as the second argument to fetch() to override default Cache Rules.
2. Dynamic cache control: Apply different caching strategies based on request headers, cookies, or other runtime conditions.
3. Per-request customization: Bypass or modify Cache Rules for individual requests while maintaining default behavior for others.
4. Programmatic cache management: Implement complex caching logic that adapts to your application's needs.

What can be configured

Workers can override the following Cache Rules settings through the cf object:

• cacheEverything: Treat all content as static and cache all file types beyond the default cached content.
• cacheTtl: Set custom time-to-live values in seconds for cached content at the edge, regardless of origin headers.
• cacheTtlByStatus: Set different TTLs based on the response status code (for example, { "200-299": 86400, 404: 1, "500-599": 0 }).
• cacheKey: Customize cache keys to control which requests are treated as the same for caching purposes (Enterprise only).
• cacheTags: Append additional cache tags for targeted cache purging operations.

Benefits

• Enhanced flexibility: Customize cache behavior without modifying zone-level Cache Rules.
• Dynamic optimization: Adjust caching strategies in real-time based on request context.
• Simplified configuration: Reduce the number of Cache Rules needed by handling edge cases programmatically.
• Improved performance: Fine-tune cache behavior for specific use cases to maximize hit rates.

Get started

To get started, refer to the Workers Fetch API documentation and the cf object properties documentation.