astro/dist/core/cache/provider-utils.js

Astro is a modern site builder with web best practices, performance, and DX front-of-mind.

/**
* Prefix used for auto-generated path tags.
* Responses are tagged with `astro-path:{pathname}` so that
* `invalidate({ path })` can be implemented via tag-based purge
* on platforms that don't support native path invalidation.
*/
const PATH_TAG_PREFIX = "astro-path:";
/**
* Generate a cache tag for a given path.
* Used by Netlify and Vercel providers to support `invalidate({ path })`.
*/
export function pathTag(path) {
	return `${PATH_TAG_PREFIX}${path}`;
}
/**
* Build cache-control directives from CacheOptions.
* Returns the directive string (e.g. `"public, max-age=300, stale-while-revalidate=60"`)
* without the header name, so each provider can use its own header
* (`Netlify-CDN-Cache-Control`, `Vercel-CDN-Cache-Control`, `Cloudflare-CDN-Cache-Control`).
*
* Returns `undefined` if no caching directives are present.
*/
export function buildCacheControlDirectives(options, extraDirectives) {
	const directives = [];
	if (extraDirectives) {
		directives.push(...extraDirectives);
	}
	if (options.maxAge !== undefined) {
		directives.push(`max-age=${options.maxAge}`);
	}
	if (options.swr !== undefined) {
		directives.push(`stale-while-revalidate=${options.swr}`);
	}
	return directives.length > 0 ? directives.join(", ") : undefined;
}
/**
* Set common conditional headers (Last-Modified, ETag) on a Headers object.
*/
export function setConditionalHeaders(headers, options) {
	if (options.lastModified) {
		headers.set("Last-Modified", options.lastModified.toUTCString());
	}
	if (options.etag) {
		headers.set("ETag", options.etag);
	}
}
/**
* Normalize `InvalidateOptions.tags` to a flat string array.
*/
export function normalizeTags(tags) {
	if (!tags) return [];
	return Array.isArray(tags) ? tags : [tags];
}
/**
* Collect all tags needed to invalidate the given options,
* including the path tag if `options.path` is set.
* Used by providers that implement path invalidation via tags
* (Netlify, Vercel) rather than native path purge (Cloudflare).
*/
export function collectInvalidationTags(options) {
	const tags = normalizeTags(options.tags);
	if (options.path) {
		tags.push(pathTag(options.path));
	}
	return tags;
}