Automatic Caching

Globe's infrastructure includes a multi-layered caching system designed to improve your application's performance. Caching is handled automatically at our global edge locations, so you benefit from it without any initial configuration.

How Automatic Caching Works

When a request for a static asset (like an image, CSS, or JavaScript file) reaches Globe's Edge Network, the following happens:

1. Cache Check: Globe checks if a fresh copy of the asset exists in the cache of the edge location that received the request.
2. Cache Hit: If a valid copy exists (a "cache hit"), the asset is served directly from the edge. This is extremely fast and does not count against your project's uncached bandwidth.
3. Cache Miss: If the asset is not in the cache or has expired (a "cache miss"), the request is forwarded to a compute region. Your application processes the request, and the response is sent back to the user and stored in the edge cache for future requests.

New deployments automatically invalidate the entire cache, ensuring your users always receive the latest version of your assets.

Controlling Cache Behavior

While caching is automatic, you can fine-tune its behavior using standard HTTP Cache-Control headers in your responses. This gives you precise control over what is cached and for how long.

Key Headers:

• Cache-Control: The primary header to define a caching policy. Use public to allow caching and max-age to specify the duration in seconds.
• ETag: A unique identifier for a specific version of a resource, used for validation.

Example in Dart (Shelf):

Here is how you can control caching for a static asset, telling browsers and Globe's edge to cache it for 24 hours.

import 'package:shelf/shelf.dart';

Response handleAssetRequest(Request request) {
  // Your logic to get assetContent
  final assetContent = ...;
  final etag = computeETag(assetContent); // A function to generate a unique hash

  return Response.ok(assetContent, headers: {
    'Cache-Control': 'public, max-age=86400', // Cache for 24 hours
    'ETag': etag,
  });
}

By effectively leveraging these headers, you can optimize asset delivery, reduce the load on your application, and minimize bandwidth costs.