import { RequestResponseInterface } from "../../frameworks/interface.ts";
interface FeaturePolicyOptions { features: {[featureName: string]: string[]};}
function isPlainObject(value: unknown): value is {[key: string]: unknown} { return ( typeof value === 'object' && !Array.isArray(value) && value !== null );}
function getHeaderValueFromOptions(options: unknown): string { const FEATURES: {[featureKeyCamelCase: string]: string} = { accelerometer: 'accelerometer', ambientLightSensor: 'ambient-light-sensor', autoplay: 'autoplay', battery: 'battery', camera: 'camera', displayCapture: 'display-capture', documentDomain: 'document-domain', documentWrite: 'document-write', encryptedMedia: 'encrypted-media', executionWhileNotRendered: 'execution-while-not-rendered', executionWhileOutOfViewport: 'execution-while-out-of-viewport', fontDisplayLateSwap: 'font-display-late-swap', fullscreen: 'fullscreen', geolocation: 'geolocation', gyroscope: 'gyroscope', layoutAnimations: 'layout-animations', legacyImageFormats: 'legacy-image-formats', loadingFrameDefaultEager: 'loading-frame-default-eager', magnetometer: 'magnetometer', microphone: 'microphone', midi: 'midi', navigationOverride: 'navigation-override', notifications: 'notifications', oversizedImages: 'oversized-images', payment: 'payment', pictureInPicture: 'picture-in-picture', publickeyCredentials: 'publickey-credentials', push: 'push', serial: 'serial', speaker: 'speaker', syncScript: 'sync-script', syncXhr: 'sync-xhr', unoptimizedImages: 'unoptimized-images', unoptimizedLosslessImages: 'unoptimized-lossless-images', unoptimizedLossyImages: 'unoptimized-lossy-images', unsizedMedia: 'unsized-media', usb: 'usb', verticalScroll: 'vertical-scroll', vibrate: 'vibrate', vr: 'vr', wakeLock: 'wake-lock', xr: 'xr', xrSpatialTracking: 'xr-spatial-tracking', };
if (!isPlainObject(options)) { throw new Error('featurePolicy must be called with an object argument. See the documentation.'); }
const { features } = options; if (!isPlainObject(features)) { throw new Error('featurePolicy must have a single key, "features", which is an object of features. See the documentation.'); }
const result = Object.entries(features).map(([featureKeyCamelCase, featureValue]) => { if (!Object.prototype.hasOwnProperty.call(FEATURES, featureKeyCamelCase)) { throw new Error(`featurePolicy does not support the "${ featureKeyCamelCase }" feature.`); }
if (!Array.isArray(featureValue) || featureValue.length === 0) { throw new Error(`The value of the "${featureKeyCamelCase}" feature must be a non-empty array of strings.`); }
const allowedValuesSeen: Set<string> = new Set();
featureValue.forEach((allowedValue) => { if (typeof allowedValue !== 'string') { throw new Error(`The value of the "${featureKeyCamelCase}" feature contains a non-string, which is not supported.`); } else if (allowedValuesSeen.has(allowedValue)) { throw new Error(`The value of the "${featureKeyCamelCase}" feature contains duplicates, which it shouldn't.`); } else if (allowedValue === 'self') { throw new Error("'self' must be quoted."); } else if (allowedValue === 'none') { throw new Error("'none' must be quoted."); } allowedValuesSeen.add(allowedValue); });
if (featureValue.length > 1) { if (allowedValuesSeen.has('*')) { throw new Error(`The value of the "${featureKeyCamelCase}" feature cannot contain * and other values.`); } else if (allowedValuesSeen.has("'none'")) { throw new Error(`The value of the "${featureKeyCamelCase}" feature cannot contain 'none' and other values.`); } }
const featureKeyDashed = FEATURES[featureKeyCamelCase]; return [featureKeyDashed, ...featureValue].join(' '); }).join(';');
if (result.length === 0) { throw new Error('At least one feature is required.'); }
return result;}
export default function featurePolicy (requestResponse: RequestResponseInterface, options: FeaturePolicyOptions) { if (options !== undefined) { const headerValue = getHeaderValueFromOptions(options);
requestResponse.setResponseHeader('Feature-Policy', headerValue); }};