fluxer/packages/hono/src/Session.tsx
2026-02-17 12:22:36 +00:00

99 lines
2.7 KiB
TypeScript

/*
* Copyright (C) 2026 Fluxer Contributors
*
* This file is part of Fluxer.
*
* Fluxer is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Fluxer is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with Fluxer. If not, see <https://www.gnu.org/licenses/>.
*/
import {createHmac, timingSafeEqual} from 'node:crypto';
export interface SessionConfig {
secretKey: string;
maxAgeSeconds?: number;
}
const DEFAULT_MAX_AGE_SECONDS = 60 * 60 * 24 * 7;
function signData(data: string, secretKey: string): string {
const signature = createHmac('sha256', secretKey).update(data).digest('base64url');
return `${data}.${signature}`;
}
function verifySignature(signedData: string, secretKey: string): string | null {
const dotIndex = signedData.lastIndexOf('.');
if (dotIndex === -1) {
return null;
}
const data = signedData.slice(0, dotIndex);
const providedSignature = signedData.slice(dotIndex + 1);
const expectedSignature = createHmac('sha256', secretKey).update(data).digest('base64url');
try {
const providedBuffer = Buffer.from(providedSignature, 'base64url');
const expectedBuffer = Buffer.from(expectedSignature, 'base64url');
if (providedBuffer.length !== expectedBuffer.length) {
return null;
}
if (timingSafeEqual(providedBuffer, expectedBuffer)) {
return data;
}
} catch {
return null;
}
return null;
}
export function createSession<T extends object>(data: T, secretKey: string): string {
const sessionWithTimestamp = {
...data,
createdAt: Math.floor(Date.now() / 1000),
};
const encoded = Buffer.from(JSON.stringify(sessionWithTimestamp)).toString('base64url');
return signData(encoded, secretKey);
}
export function parseSession<T extends object>(
cookie: string,
secretKey: string,
maxAgeSeconds: number = DEFAULT_MAX_AGE_SECONDS,
): (T & {createdAt: number}) | null {
const data = verifySignature(cookie, secretKey);
if (!data) {
return null;
}
try {
const decoded = Buffer.from(data, 'base64url').toString('utf-8');
const session = JSON.parse(decoded) as T & {createdAt: number};
if (typeof session.createdAt !== 'number') {
return null;
}
const now = Math.floor(Date.now() / 1000);
if (now - session.createdAt > maxAgeSeconds) {
return null;
}
return session;
} catch {
return null;
}
}