Rewrite reducing crypto complexity

package.json

@@ -10,6 +10,7 @@
     "@types/body-parser": "^1.19.2",
     "@types/express": "^4.17.17",
     "@types/jest": "~29.5",
+    "@types/jsonwebtoken": "^9.0.2",
     "@types/node": "~18",
     "@types/sqlite3": "^3.1.8",
     "@typescript-eslint/eslint-plugin": "^6.3.0",
@@ -42,10 +43,14 @@
     "body-parser": "^1.20.2",
     "elliptic": "^6.5.4",
     "express": "^4.18.2",
+    "http_ece": "^1.1.0",
+    "jsonwebtoken": "^9.0.1",
+    "node-fetch": "^3.3.2",
+    "reflect-metadata": "^0.1.13",
     "sqlite": "^5.0.1",
     "sqlite3": "^5.1.6",
     "tslib": "~2.6",
-    "web-push": "^3.6.4"
+    "typeorm": "^0.3.17"
   },
   "volta": {
     "node": "18.12.1"

src/WebPushSender.ts

@@ -1,66 +0,0 @@
-import fetch from 'node-fetch';
-import * as crypto from 'crypto';
-import { ec as EC } from 'elliptic';
-
-export class WebPushSender {
-  private ec = new EC('prime256v1');
-  private vapidPrivateKey: string;
-
-  constructor(vapidPrivateKey: string) {
-    this.vapidPrivateKey = vapidPrivateKey;
-  }
-
-  private generateECDHKeyPair() {
-    return this.ec.genKeyPair();
-  }
-
-  private deriveSharedSecret(senderKeys, receiverPublicKeyBase64: string) {
-    const receiverPublicKey = Buffer.from(receiverPublicKeyBase64, 'base64');
-    return senderKeys.derive(this.ec.keyFromPublic(receiverPublicKey).getPublic());
-  }
-
-  private generateContentEncryptionKeys(sharedSecret, authSecretBase64: string) {
-    const authSecret = Buffer.from(authSecretBase64, 'base64');
-    const info = Buffer.from('Content-Encoding: auth\0', 'utf8');
-    const prk = crypto.createHmac('sha256', authSecret).update(sharedSecret.toArray()).digest();
-    const context = crypto.createHmac('sha256', prk).update(info).digest();
-    const keyInfo = Buffer.from('Content-Encoding: aes128gcm\0', 'utf8');
-    return crypto.createHmac('sha256', context).update(keyInfo).digest().slice(0, 16);
-  }
-
-  private encryptPayload(contentEncryptionKey, payload: string) {
-    const nonce = Buffer.alloc(12);
-    const cipher = crypto.createCipheriv('aes-128-gcm', contentEncryptionKey, nonce);
-    return Buffer.concat([cipher.update(payload, 'utf8'), cipher.final()]);
-  }
-
-  private generateVapidToken(endpoint: string) {
-    const tokenPayload = {
-      aud: endpoint,
-      exp: Math.floor(Date.now() / 1000) + (24 * 60 * 60), // 24 hours
-      sub: 'mailto:your-email@example.com',
-    };
-    const encodedHeader = Buffer.from(JSON.stringify({ alg: 'ES256', typ: 'JWT' })).toString('base64');
-    const encodedPayload = Buffer.from(JSON.stringify(tokenPayload)).toString('base64');
-    const signature = this.ec.sign(encodedHeader + '.' + encodedPayload, this.vapidPrivateKey, 'base64');
-    const encodedSignature = signature.toDER('hex');
-    return `${encodedHeader}.${encodedPayload}.${encodedSignature}`;
-  }
-
-  public sendPushNotification(subscription, payload: string) {
-    const senderKeys = this.generateECDHKeyPair();
-    const sharedSecret = this.deriveSharedSecret(senderKeys, subscription.keys.p256dh);
-    const contentEncryptionKey = this.generateContentEncryptionKeys(sharedSecret, subscription.keys.auth);
-    const encryptedPayload = this.encryptPayload(contentEncryptionKey, payload);
-    const vapidToken = this.generateVapidToken(subscription.endpoint);
-
-    const headers = {
-      'Content-Encoding': 'aes128gcm',
-      'Authorization': `vapid t=${vapidToken}`,
-      'TTL': '60',
-    };
-
-    return fetch(subscription.endpoint, { method: 'POST', body: encryptedPayload, headers });
-  }
-}
-

src/main.ts

@@ -1,68 +1,12 @@
-
 import express from 'express';
 import bodyParser from 'body-parser';
-import { Request, Response } from 'express';
+import router from './routes.js';
-import sqlite3 from 'sqlite3';
-import { open } from 'sqlite';
-import { WebPushSender } from './WebPushSender.js';
 
-class PushService {
+const app = express();
-  private app = express();
-  private db: any;
-  private sender: WebPushSender;
-  private port: number;
 
-  constructor(port: number, vapidPrivateKey: string) {
+app.use(bodyParser.json());
-    this.port = port;
+app.use(router);
-    this.sender = new WebPushSender(vapidPrivateKey);
-    this.app.use(bodyParser.json());
 
-    open({ filename: './subscriptions.db', driver: sqlite3.Database }).then((db) => {
+app.listen(3000, () => {
-      this.db = db;
+  console.log('Server is running on port 3000');
-      this.db.run('CREATE TABLE IF NOT EXISTS subscriptions (p256dh TEXT PRIMARY KEY, endpoint TEXT, auth TEXT)');
+});
-      this.setupRoutes();
-    });
-  }
-
-  private setupRoutes() {
-    this.app.post('/subscribe', this.handleSubscribe.bind(this));
-  }
-
-  private async handleSubscribe(req: Request, res: Response) {
-    const { endpoint, keys } = req.body;
-    const { p256dh, auth } = keys;
-
-    try {
-      await this.db.run('INSERT INTO subscriptions (p256dh, endpoint, auth) VALUES (?, ?, ?)', [p256dh, endpoint, auth]);
-      res.status(201).send('Subscription created successfully');
-    } catch (err) {
-      res.status(400).send('Failed to create subscription');
-    }
-  }
-
-  public async sendNotification(p256dh: string, payload: string) {
-    const row = await this.db.get('SELECT * FROM subscriptions WHERE p256dh = ?', [p256dh]);
-    if (row) {
-      const subscription = {
-        endpoint: row.endpoint,
-        keys: {
-          p256dh: row.p256dh,
-          auth: row.auth,
-        },
-      };
-
-      return this.sender.sendPushNotification(subscription, payload);
-    } else {
-      throw new Error('Subscription not found');
-    }
-  }
-
-  public start() {
-    this.app.listen(this.port, () => {
-      console.log(`Server running on http://localhost:${this.port}`);
-    });
-  }
-}
-
-const pushService = new PushService(3000, 'YOUR_PRIVATE_VAPID_KEY');
-pushService.start();

src/routes.ts

@@ -0,0 +1,28 @@
+import express from 'express';
+import { saveSubscription, getSubscriptions } from './subscriptions.js';
+import { WebPushService } from './webpush.js';
+
+const router = express.Router();
+
+router.post('/subscribe', (req, res) => {
+  const subscription = req.body;
+  saveSubscription(subscription);
+  res.status(201).send();
+});
+
+router.post('/sendNotification', (_, res) => {
+  const webPush = new WebPushService();
+  const subscriptions = getSubscriptions();
+  const data = {
+    title: "Notification Title",
+    message: "This is a message from your web push server"
+  };
+  
+  for (let sub of subscriptions) {
+    webPush.sendNotification(sub, data);
+  }
+
+  res.status(201).send();
+});
+
+export default router;

src/subscriptions.ts

@@ -0,0 +1,18 @@
+export type Subscription = {
+    endpoint: string;
+    keys: {
+      p256dh: string;
+      auth: string;
+    };
+  };
+  
+  let subscriptions: Subscription[] = [];
+  
+  export function saveSubscription(sub: Subscription) {
+    subscriptions.push(sub);
+  }
+  
+  export function getSubscriptions(): Subscription[] {
+    return subscriptions;
+  }
+  

src/webpush.ts

@@ -0,0 +1,82 @@
+import * as http_ece from 'http_ece';
+import { Subscription } from './subscriptions.js';
+import * as jwt from 'jsonwebtoken';
+import * as https from 'https';
+
+export class WebPushService {
+
+    private vapidPrivateKey = 'YOUR_VAPID_PRIVATE_KEY';
+    private vapidPublicKey = 'YOUR_VAPID_PUBLIC_KEY';
+
+    async sendNotification(subscription: Subscription, data: any) {
+        const payload = JSON.stringify(data);
+
+        // Encrypt the payload
+        const encrypted = this.encrypt(subscription.keys.p256dh, subscription.keys.auth, payload);
+
+        // VAPID headers
+        const vapidHeaders = this.createVapidAuthHeader();
+
+        // Send the encrypted data to the endpoint
+        const parsedUrl = new URL(subscription.endpoint);
+        const options: https.RequestOptions = {
+          method: 'POST',
+          hostname: parsedUrl.hostname,
+          path: parsedUrl.pathname,
+          port: parsedUrl.port,
+          headers: {
+            ...vapidHeaders,
+            'TTL': '60', // Time-to-live in seconds
+            'Content-Encoding': 'aes128gcm',
+            'Content-Type': 'application/octet-stream',
+            'Content-Length': encrypted.length
+          },
+        };
+    
+        return new Promise<void>((resolve, reject) => {
+          const req = https.request(options, (res) => {
+            if (res.statusCode! >= 200 && res.statusCode! < 300) {
+              resolve();
+            } else {
+              reject(new Error(`Failed to send push notification. Status code: ${res.statusCode}`));
+            }
+          });
+    
+          req.on('error', (error) => {
+            reject(new Error(`Failed to send push notification. Error: ${error.message}`));
+          });
+    
+          req.write(encrypted);
+          req.end();
+        });        
+    }
+
+    encrypt(publicKey: string, auth: string, payload: string): Buffer {
+        http_ece.keys = {
+            'p256dh': publicKey,
+            'auth': auth
+        };
+
+        return http_ece.encrypt(payload, {
+            'salt': 'randomSalt',  // Ideally, you should generate a unique salt for every message.
+            'dh': 'yourVAPIDPublicKey',
+            'keyid': 'p256dh',
+            'contentEncoding': 'aes128gcm'
+        });
+    }
+
+    private createVapidAuthHeader(): { Authorization: string, 'Crypto-Key': string } {
+        const jwtPayload = {
+            aud: 'https://fcm.googleapis.com',
+            exp: Math.round(Date.now() / 1000) + (24 * 3600), // 24 hours
+            sub: 'mailto:your@email.com'
+        };
+
+        const token = jwt.sign(jwtPayload, this.vapidPrivateKey, { algorithm: 'ES256' });
+
+        return {
+            Authorization: `Bearer ${token}`,
+            'Crypto-Key': `p256ecdsa=${this.vapidPublicKey}`
+        };
+    }
+}

tsconfig.json

@@ -1,5 +1,6 @@
 {
   "compilerOptions": {
+    "esModuleInterop": true,
     "target": "es2022",
     "module": "node16",
     "lib": ["ES2022"],
@@ -17,7 +18,9 @@
     "noUnusedParameters": true,
     "noImplicitAny": false,
     "noImplicitThis": false,
-    "strictNullChecks": false
+    "strictNullChecks": false,
+    "experimentalDecorators": true,
+    "emitDecoratorMetadata": true    
   },
   "include": ["src/**/*", "__tests__/**/*"]
 }

tsconfig.release.json

@@ -4,5 +4,6 @@
     "sourceMap": false,
     "removeComments": true
   },
-  "include": ["src/**/*"]
+  "include": ["src/**/*"],
+  "exclude": ["node_modules"]
 }