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import dotenv from 'dotenv';
import express, { Request, Response } from 'express';
import { randomBytes } from 'crypto';
import qrcode from 'qrcode';
import { generateDigiIDUri, verifyDigiIDCallback } from 'digiid-ts';
// Load environment variables from .env file
dotenv.config();
const app = express();
const PORT = process.env.PORT || 3001;
// In-memory storage for demo purposes
interface SessionState {
nonce: string;
status: 'pending' | 'success' | 'failed';
address?: string;
error?: string;
}
const sessionStore = new Map<string, SessionState>();
const nonceToSessionMap = new Map<string, string>();
// Middleware
app.use(express.json());
console.log('Server starting...');
console.log(`Attempting to listen on port: ${PORT}`);
console.log(`Configured PUBLIC_URL: ${process.env.PUBLIC_URL}`);
// Endpoint to initiate the DigiID authentication flow
app.get('/api/digiid/start', async (req: Request, res: Response) => {
try {
const sessionId = randomBytes(16).toString('hex');
const nonce = randomBytes(16).toString('hex');
const publicUrl = process.env.PUBLIC_URL;
if (!publicUrl) {
console.error('PUBLIC_URL environment variable is not set.');
return res.status(500).json({ error: 'Server configuration error: PUBLIC_URL is missing.' });
}
let callbackUrl: string;
try {
const baseUrl = new URL(publicUrl);
callbackUrl = new URL('/api/digiid/callback', baseUrl).toString();
} catch (error) {
console.error('Invalid PUBLIC_URL format:', publicUrl, error);
return res.status(500).json({ error: 'Server configuration error: Invalid PUBLIC_URL format.' });
}
const unsecure = callbackUrl.startsWith('http://');
// Use the actual function from digiid-ts
const digiIdUri = generateDigiIDUri({ callbackUrl, unsecure, nonce });
console.log(`Generated DigiID URI: ${digiIdUri} for session ${sessionId}`);
sessionStore.set(sessionId, { nonce, status: 'pending' });
nonceToSessionMap.set(nonce, sessionId);
console.log(`Stored pending session: ${sessionId}, nonce: ${nonce}`);
const qrCodeDataUrl = await qrcode.toDataURL(digiIdUri);
res.json({ sessionId, qrCodeDataUrl });
} catch (error) {
console.error('Error in /api/digiid/start:', error);
// Ensure response is sent even on error
if (!res.headersSent) { // Check if response hasn't already been sent
if (error instanceof Error) {
res.status(400).json({ error: `Failed to generate URI: ${error.message}` });
} else {
res.status(500).json({ error: 'Internal server error during start' });
}
}
}
});
// Callback endpoint for the DigiID mobile app
app.post('/api/digiid/callback', async (req: Request, res: Response) => {
const { address, uri, signature } = req.body;
// Basic validation of received data
if (!address || !uri || !signature) {
console.warn('Callback missing required fields.', { address, uri, signature });
// Wallet doesn't expect a body on failure, just non-200. Status only for logging/debug.
return res.status(400).send('Missing required callback parameters.');
}
const callbackData = { address, uri, signature };
console.log('Received callback:', callbackData);
// --- Nonce Extraction and Session Lookup ---
let receivedNonce: string | null = null;
try {
// DigiID URIs need scheme replaced for standard URL parsing
const parsableUri = uri.replace(/^digiid:/, 'http:');
const parsedUri = new URL(parsableUri);
receivedNonce = parsedUri.searchParams.get('x');
} catch (error) {
console.warn('Error parsing received URI:', uri, error);
return res.status(400).send('Invalid URI format.');
}
if (!receivedNonce) {
console.warn('Nonce (x parameter) not found in received URI:', uri);
return res.status(400).send('Nonce not found in URI.');
}
const sessionId = nonceToSessionMap.get(receivedNonce);
if (!sessionId) {
console.warn('Session not found for received nonce:', receivedNonce);
// Nonce might be expired or invalid
return res.status(404).send('Session not found or expired for this nonce.');
}
// Retrieve the session *before* the try/finally block for verification
const session = sessionStore.get(sessionId);
if (!session) {
console.error(`Critical: Session data missing for ${sessionId} despite nonce match.`);
if (!res.headersSent) res.status(500).send('Internal server error: Session data missing.');
return; // Explicitly return void
}
if (session.status !== 'pending') {
console.warn('Session already processed:', sessionId, session.status);
if (!res.headersSent) res.status(200).send('Session already processed.');
return; // Explicitly return void
}
// --- Verification ---
let expectedCallbackUrl: string;
try {
const publicUrl = process.env.PUBLIC_URL;
if (!publicUrl) throw new Error('PUBLIC_URL environment variable is not configured on the server.');
expectedCallbackUrl = new URL('/api/digiid/callback', publicUrl).toString();
} catch (error) {
console.error('Server configuration error constructing expected callback URL:', error);
session.status = 'failed';
session.error = 'Server configuration error preventing verification.';
sessionStore.set(sessionId, session);
// Respond 200 OK as per protocol
if (!res.headersSent) res.status(200).send();
return; // Explicitly return void
}
const verifyOptions = { expectedCallbackUrl, expectedNonce: session.nonce };
try {
console.log('Attempting to verify callback with:', { callbackData, verifyOptions });
await verifyDigiIDCallback(callbackData, verifyOptions);
// Success case (no throw from verifyDigiIDCallback)
console.log(`Verification successful for session ${sessionId}, address: ${address}`);
session.status = 'success';
session.address = address; // Store the verified address
session.error = undefined; // Clear any previous error
nonceToSessionMap.delete(session.nonce); // Clean up nonce map only on success
} catch (error) {
// Failure case (verifyDigiIDCallback threw an error)
console.warn(`Verification failed for session ${sessionId}:`, error);
session.status = 'failed';
if (error instanceof Error) {
session.error = error.message;
} else {
session.error = 'An unknown verification error occurred.';
}
// Optionally cleanup nonce map on failure too, depending on policy
// nonceToSessionMap.delete(session.nonce);
} finally {
// Update store and respond 200 OK in all cases (after try/catch)
sessionStore.set(sessionId, session);
console.log(`Final session state for ${sessionId}:`, session);
// Ensure response is sent if not already done (e.g. in case of unexpected error before finally)
if (!res.headersSent) {
res.status(200).send();
}
// No explicit return needed here as it's the end of the function
}
});
// Endpoint to check the status of an authentication session
app.get('/api/digiid/status/:sessionId', (req: Request, res: Response) => {
const { sessionId } = req.params;
const session = sessionStore.get(sessionId);
if (!session) {
res.status(404).json({ status: 'not_found' });
return; // Keep explicit return
}
const { status, address, error } = session;
res.json({ status, address, error });
});
// Simple root endpoint
app.get('/', (_: Request, res: Response) => {
res.send('DigiID Demo Backend Running!');
});
// Start the server
app.listen(PORT, () => {
console.log(`Server listening on port ${PORT}`);
});
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