downloadable file delivery.md

Migrate Cloudflare CDN configuration: Downloadable file delivery

Summary

Move CDN delivery from Cloudflare CDN configuration to Ample, one component at a time. Destination verified on Ample: a generated CSV stored with a Content-Disposition attachment header and served from the CDN URL with that header intact, so browsers download it under the stored filename. Source procedure: Record page rules, cache rules and the asset paths the app references. Not migrated automatically: Cloudflare cache rules, Workers, Transform Rules and tiered caching are not migrated; Ample verifies delivery of published bucket objects only. Cutover: Redeploy the app with the new asset base URL, verify delivery from the CDN URL, then retire the old cache rules. Rollback: keep the source untouched until you confirm; nothing at the source is changed or deleted by this guide.

Infrastructure requirements

CDN: verified (The CDN host serves objects from published buckets. It does not front app compute and is not a cache or key-value store.)

Prerequisites

Authorized access to the Cloudflare CDN configuration source and its export tooling
An inventory of every component in scope and out of scope
A validated backup or copy before any cutover
An Ample account token with servers:write, buckets:write

Exact tested configuration

template: node-22
runtime: node
size: s-1vcpu-1gb
install: npm install
build: npm run build --if-present
start: npm run start

Steps

Inventory the source. List what Cloudflare CDN configuration provides beyond the component you are moving. Out of scope here: Cloudflare cache rules, Workers, Transform Rules and tiered caching are not migrated; Ample verifies delivery of published bucket objects only.
Source step 1. Record page rules, cache rules and the asset paths the app references
Source step 2. Copy the public assets into a published Ample bucket under versioned keys with immutable Cache-Control
Source step 3. Update the app to build asset URLs from the Ample public URL
Publish the destination bucket. Create and publish the asset bucket, upload versioned assets with immutable Cache-Control, and point the app at the public URL.
```
ample bucket publish <bucket-name>
```
Validate before cutover. Run the app's own checks and, for data, compare counts and checksums; the example checks are the pattern self-tests (/p/downloadable-file-delivery).
Cut over. Redeploy the app with the new asset base URL, verify delivery from the CDN URL, then retire the old cache rules.
Rollback. Point DNS or configuration back to the source. The source was never modified; deletion is a separate, user-executed step after validation.

Tested examples

Next.js pattern fixture (destination) (tests/deploy-canaries/next-js-patterns): Verified destination basis: downloadable file delivery.

Success checks

destination app responds on its public URL (/ on the live URL, expect ample canary next js patterns)
downloadable-file-delivery check from the destination example (/p/downloadable-file-delivery on the live URL, expect see the pattern fixture checks)
data or object counts and checksums match the source

Limitations

Documentation only: nothing is executed automatically and no execution binding is offered.
The source-side procedure is documented from Cloudflare CDN configuration's standard tooling and was not executed in this catalog's evidence; the destination side was verified with the pattern fixture.
No full source-product parity is claimed: Cloudflare cache rules, Workers, Transform Rules and tiered caching are not migrated; Ample verifies delivery of published bucket objects only.
Verified on the node-22 template at s-1vcpu-1gb; region, compliance and request-duration limits are unknown.
PutObject and GetObject with path-style addressing are verified; bulk copy tooling and other S3 operations are not.

Cost estimate

Estimated 5.00 USD per month (size prices from pricing.toml at build revision a1b8c38919e59cd035ebabaced73cf84ece24371).

app server x1 s-1vcpu-1gb: 5.00 USD

Verification evidence

canary_run on 2026-09-21T02:34:39Z at revision 1d28ae0-dirty (CLI 0.1.21): Destination side verified: the Next.js pattern fixture deployed on Ample (next build then next start -H 0.0.0.0 -p $PORT on the node-22 template) and its checks passed (a generated CSV stored with a Content-Disposition attachment header and served from the CDN URL with that header intact, so browsers download it under the stored filename). The source-side export from Cloudflare CDN configuration is documented from the vendor's standard tooling and was not executed by this catalog's evidence. (expires 2027-03-20T02:34:39Z)

Execution binding

No execution binding. This recipe is documentation only; nothing is executed automatically.