@directus/api/dist/utils/get-cache-headers.js

Directus is a real-time API and App dashboard for managing SQL database content

import { useEnv } from '@directus/env';
import { shouldSkipCache } from './should-skip-cache.js';
/**
 * Returns the Cache-Control header for the current request
 *
 * @param req Express request object
 * @param ttl TTL of the cache in ms
 * @param globalCacheSettings Whether requests are affected by the global cache settings (i.e. for dynamic API requests)
 * @param personalized Whether requests depend on the authentication status of users
 */
export function getCacheControlHeader(req, ttl, globalCacheSettings, personalized) {
    const env = useEnv();
    // When the user explicitly asked to skip the cache
    if (shouldSkipCache(req))
        return 'no-store';
    // When the resource / current request shouldn't be cached
    if (ttl === undefined || ttl < 0)
        return 'no-cache';
    // When the API cache can invalidate at any moment
    if (globalCacheSettings && env['CACHE_AUTO_PURGE'] === true)
        return 'no-cache';
    const headerValues = [];
    // When caching depends on the authentication status of the users
    if (personalized) {
        // Allow response to be stored in shared cache (public) or local cache only (private)
        const access = !!req.accountability?.role === false ? 'public' : 'private';
        headerValues.push(access);
    }
    // Cache control header uses seconds for everything
    const ttlSeconds = Math.round(ttl / 1000);
    headerValues.push(`max-age=${ttlSeconds}`);
    // When the s-maxage flag should be included
    if (globalCacheSettings &&
        Number.isInteger(env['CACHE_CONTROL_S_MAXAGE']) &&
        env['CACHE_CONTROL_S_MAXAGE'] >= 0) {
        headerValues.push(`s-maxage=${env['CACHE_CONTROL_S_MAXAGE']}`);
    }
    return headerValues.join(', ');
}