@trillet-ai/web-sdk/dist/BrowserFingerprint.js

Trillet Web SDK for real-time audio communication with AI agents

/**
 * Browser Fingerprinting Utility
 * Generates a deterministic fingerprint based on stable browser/hardware characteristics.
 * Used for demo link usage limit tracking.
 *
 * Strategy:
 *   1. localStorage persistence — generate once, reuse across tabs/sessions forever
 *   2. Stable hardware-only seed — if storage is cleared, the same hardware signals
 *      produce the same hash, so the fingerprint stays consistent
 *   3. Server-side IP fallback — handled by the backend when no fingerprint is sent
 */
const STORAGE_KEY = 'trillet_dfp';
export class BrowserFingerprint {
    /**
     * Generate (or retrieve) a deterministic browser fingerprint.
     * Cached in memory → localStorage → derived from stable hardware signals.
     */
    static async generate() {
        // 1. In-memory cache (fastest)
        if (this.cachedFingerprint) {
            return this.cachedFingerprint;
        }
        // 2. Persisted in localStorage (survives tab close / browser restart)
        const stored = this.getStored();
        if (stored) {
            this.cachedFingerprint = stored;
            return stored;
        }
        // 3. Derive from stable hardware signals and persist
        const signals = this.getStableSignals();
        const fingerprint = await this.hashComponents(signals);
        this.persist(fingerprint);
        this.cachedFingerprint = fingerprint;
        return fingerprint;
    }
    /**
     * Collect only hardware / environment signals that do NOT change between
     * tabs, sessions, or browser restarts on the same device.
     *
     * Deliberately excluded (volatile / anti-fingerprint randomised):
     *   - canvas.toDataURL()  — randomised per origin in many browsers
     *   - font detection       — noisy across rendering states
     *   - screen.availWidth/Height — changes with taskbar / dock resize
     *   - navigator.doNotTrack — user can toggle
     *   - timezoneOffset       — changes with DST
     *   - navigator.userAgent  — changes on browser update
     */
    static getStableSignals() {
        return {
            // Hardware — fixed for a given device
            screen: {
                width: window.screen.width,
                height: window.screen.height,
                colorDepth: window.screen.colorDepth,
                pixelRatio: window.devicePixelRatio,
            },
            hardwareConcurrency: navigator.hardwareConcurrency,
            deviceMemory: navigator.deviceMemory,
            platform: navigator.platform,
            maxTouchPoints: navigator.maxTouchPoints,
            // WebGL vendor/renderer — GPU-based, stable
            webgl: this.getWebGLFingerprint(),
            // Locale — stable unless user changes OS language or moves timezone
            timezone: Intl.DateTimeFormat().resolvedOptions().timeZone,
            language: navigator.language,
        };
    }
    /**
     * WebGL vendor + renderer string (GPU identifier, very stable)
     */
    static getWebGLFingerprint() {
        try {
            const canvas = document.createElement('canvas');
            const gl = canvas.getContext('webgl') || canvas.getContext('experimental-webgl');
            if (!gl)
                return 'no-webgl';
            const glContext = gl;
            const debugInfo = glContext.getExtension('WEBGL_debug_renderer_info');
            const vendor = debugInfo
                ? glContext.getParameter(debugInfo.UNMASKED_VENDOR_WEBGL)
                : glContext.getParameter(glContext.VENDOR);
            const renderer = debugInfo
                ? glContext.getParameter(debugInfo.UNMASKED_RENDERER_WEBGL)
                : glContext.getParameter(glContext.RENDERER);
            return `${vendor}~${renderer}`;
        }
        catch (_a) {
            return 'webgl-error';
        }
    }
    /**
     * SHA-256 hash of the signals object → hex string
     */
    static async hashComponents(components) {
        const data = new TextEncoder().encode(JSON.stringify(components));
        const hashBuffer = await crypto.subtle.digest('SHA-256', data);
        return Array.from(new Uint8Array(hashBuffer))
            .map((b) => b.toString(16).padStart(2, '0'))
            .join('');
    }
    // ── localStorage helpers ───────────────────────────────────────────
    static getStored() {
        try {
            return localStorage.getItem(STORAGE_KEY);
        }
        catch (_a) {
            return null;
        }
    }
    static persist(fingerprint) {
        try {
            localStorage.setItem(STORAGE_KEY, fingerprint);
        }
        catch (_a) {
            // Storage full or disabled — fingerprint still works in-memory
        }
    }
    /**
     * Clear both in-memory and persisted fingerprint (useful for testing)
     */
    static clearCache() {
        this.cachedFingerprint = null;
        try {
            localStorage.removeItem(STORAGE_KEY);
        }
        catch (_a) {
            // Ignore
        }
    }
}
BrowserFingerprint.cachedFingerprint = null;