refactor progress

packages/media_proxy_utils/src/MediaProxySigner.tsx

@@ -0,0 +1,61 @@
+/*
+ * 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 crypto from 'node:crypto';
+
+const BASE64_URL_PADDING_REGEX = /=*$/;
+
+export interface MediaProxySignerOptions {
+	mediaProxySecretKey: string;
+}
+
+export interface IMediaProxySigner {
+	createSignature(proxyUrlPath: string): string;
+	verifySignature(proxyUrlPath: string, providedSignature: string): boolean;
+}
+
+class MediaProxySigner implements IMediaProxySigner {
+	private readonly mediaProxySecretKey: string;
+
+	constructor(options: MediaProxySignerOptions) {
+		this.mediaProxySecretKey = options.mediaProxySecretKey;
+	}
+
+	createSignature(proxyUrlPath: string): string {
+		const hmac = crypto.createHmac('sha256', this.mediaProxySecretKey);
+		hmac.update(proxyUrlPath);
+		return hmac.digest('base64url').replace(BASE64_URL_PADDING_REGEX, '');
+	}
+
+	verifySignature(proxyUrlPath: string, providedSignature: string): boolean {
+		const expectedSignature = this.createSignature(proxyUrlPath);
+		const expectedBuffer = Buffer.from(expectedSignature, 'utf8');
+		const providedBuffer = Buffer.from(providedSignature, 'utf8');
+
+		if (expectedBuffer.length !== providedBuffer.length) {
+			return false;
+		}
+
+		return crypto.timingSafeEqual(expectedBuffer, providedBuffer);
+	}
+}
+
+export function createMediaProxySigner(options: MediaProxySignerOptions): IMediaProxySigner {
+	return new MediaProxySigner(options);
+}