Manifest

The manifest is a JSON file at the root of the CDN branch. The Action writes it; the Worker validates and caches it.

Format

interface Manifest {
  app: string;
  mode: "commit" | "version";
  latest: string;
  files: string[];
  modules?: string[];
  timestamp: number;
}

Path structure

Files in files are relative to versions/<latest>/ on the CDN branch. The client fetches them from:

https://raw.githubusercontent.com/<repo>/<cdn-branch>/versions/<latest>/<file>

For example, if latest is "1.0.1" and files contains "assets/main.js", the client downloads:

https://raw.githubusercontent.com/my-org/my-app/cdn/versions/v1.0.1/assets/main.js

Module detection

The Action scans all HTML files in the build output for <script type="module" src="..."> tags. Matching files are listed in the modules array. The client uses this to pass isModule: true to swapScript, which creates the replacement with type="module".

This field is optional. If no module scripts are found, it is omitted from the manifest.

Validation

The Worker validates every manifest it reads, both from the upstream GitHub fetch and from the KV cache.

type ValidationResult =
  | { valid: true; manifest: Manifest }
  | { valid: false; errors: ValidationError[] };

Validation checks:

• app is a non-empty string
• mode is exactly "commit" or "version"
• latest is a non-empty string
• files is an array of strings
• modules (if present) is an array of strings
• timestamp is a finite positive number

Invalid manifests return a 502 error from the Worker with the validation details.

Caching

The Worker caches the manifest in KV with a configurable TTL (default 300 seconds). Set UPDATO_CACHE_TTL environment variable on the Worker to change it.

Next Steps

• GitHub Action: How the manifest is generated
• Worker: How the manifest is served and cached