@trifrost/core/esm/middleware/CacheControl.js

Blazingly fast, runtime-agnostic server framework for modern edge and node environments

import { isObject } from '@valkyriestudios/utils/object';
import { isIntGt } from '@valkyriestudios/utils/number';
import { Sym_TriFrostDescription, Sym_TriFrostFingerPrint, Sym_TriFrostName } from '../types/constants';
/* Specific symbol attached to cache control mware to identify them by */
export const Sym_TriFrostMiddlewareCacheControl = Symbol('TriFrost.Middleware.CacheControl');
var CacheControlValues;
(function (CacheControlValues) {
    /**
     * Instructs the browser that it must revalidate with the server every time before using a cached version of the URL
     */
    CacheControlValues["NoCache"] = "no-cache";
    /**
     * Instructs the browser and other intermediate caches (like CDNs) to never store any version of the file
     */
    CacheControlValues["NoStore"] = "no-store";
    /**
     * Browsers can cache the file but intermediate caches cannot
     */
    CacheControlValues["Private"] = "private";
    /**
     * Response can be stored by any cache
     */
    CacheControlValues["Public"] = "public";
})(CacheControlValues || (CacheControlValues = {}));
const CacheControlSet = new Set([...Object.values(CacheControlValues)]);
/**
 * Parse Cache Header options into a Cache-Control value
 *
 * @param {TriFrostCacheControlOptions} opts - Cache Header Options
 */
function parse(opts) {
    const parts = [];
    if (isObject(opts)) {
        /* type: no-store, no-cache, public, private */
        if (CacheControlSet.has(opts.type))
            parts.push(opts.type);
        /* max-age */
        if (isIntGt(opts.maxage, 0))
            parts.push('max-age=' + opts.maxage);
        /* s-maxage */
        if (isIntGt(opts.proxyMaxage, 0))
            parts.push('s-maxage=' + opts.proxyMaxage);
        /* immutable */
        if (opts.immutable === true)
            parts.push('immutable');
        /* must-revalidate */
        if (opts.mustRevalidate === true)
            parts.push('must-revalidate');
        /* proxy-revalidate */
        if (opts.proxyRevalidate === true)
            parts.push('proxy-revalidate');
    }
    return parts.length ? parts.join(', ') : null;
}
/**
 * Utility function which applies cache headers such as Cache-Control to a provided context
 *
 * @param {TriFrostContext} ctx - Context the headers are to be applied to
 * @param {TriFrostCacheControlOptions} opts - Cache Header Options
 */
export function ParseAndApplyCacheControl(ctx, opts) {
    const val = parse(opts);
    if (val)
        ctx.setHeader('cache-control', val);
}
/**
 * Middleware function which adds cache headers such as Cache-Control to any context passing through it
 *
 * @param {TriFrostCacheControlOptions} opts - Cache Header Options
 */
export function CacheControl(opts = {}) {
    const val = parse(opts);
    const mware = function TriFrostCacheControlMiddleware(ctx) {
        if (val)
            ctx.setHeader('cache-control', val);
    };
    /* Add symbols for introspection/use further down the line */
    Reflect.set(mware, Sym_TriFrostName, 'TriFrostCacheControl');
    Reflect.set(mware, Sym_TriFrostDescription, 'Middleware adding Cache-Control headers to contexts passing through it');
    Reflect.set(mware, Sym_TriFrostFingerPrint, Sym_TriFrostMiddlewareCacheControl);
    return mware;
}