clean up comments in server.js

Author: eiman-eltigani-ttd

web-integrations/prebid-integrations/client-server/server.js

@@ -1,16 +1,5 @@
-// ============================================================================
-// UID2 Prebid.js Client-Server Integration Example - Server
-// ============================================================================
-// This server demonstrates how to generate UID2 tokens on the server side
-// for use with Prebid.js in a client-server integration.
-//
-// Key responsibilities:
-// 1. Accept user email from the front-end
-// 2. Encrypt the email and send it to the UID2 API
-// 3. Decrypt the UID2 token response
-// 4. Return the token to the front-end for use with Prebid.js
-// ============================================================================
-
+// UID2 Prebid.js Client-Server Integration - Server
+// Generates UID2 tokens server-side for use with Prebid.js
 
 require('dotenv').config({path: '../../../.env'});
 
@@ -21,86 +10,52 @@ const crypto = require('crypto');
 const app = express();
 const port = 3052;
 
-// UID2 API Configuration
-// These values should be set via environment variables for security
+// UID2 API Configuration (set via .env file)
 const uid2BaseUrl = process.env.UID2_BASE_URL || 'https://operator-integ.uidapi.com';
-const uid2ApiKey = process.env.UID2_API_KEY;           // Your API Key from UID2 Portal
-const uid2ClientSecret = process.env.UID2_CLIENT_SECRET; // Your Client Secret from UID2 Portal
+const uid2ApiKey = process.env.UID2_API_KEY;
+const uid2ClientSecret = process.env.UID2_CLIENT_SECRET;
 
-// Encryption constants required by UID2 API
-const ivLength = 12;                  
-const nonceLength = 8;                 
-const timestampLength = 8;              
-const encryptionAlgo = 'aes-256-gcm';  
+// Encryption constants
+const ivLength = 12;
+const nonceLength = 8;
+const timestampLength = 8;
+const encryptionAlgo = 'aes-256-gcm';
 
-// Middleware setup
-app.use(express.static('public'));     
-app.use(express.json());               
-app.use(express.urlencoded({ extended: true })); 
+// Middleware
+app.use(express.static('public'));
+app.use(express.json());
+app.use(express.urlencoded({ extended: true }));
 
 // ============================================================================
-// HELPER FUNCTIONS FOR ENCRYPTION/DECRYPTION
+// Encryption/Decryption Helpers
 // ============================================================================
-// The UID2 API requires all requests and responses to be encrypted for security.
-// These functions handle the encryption/decryption process.
-
-/**
- * Converts a Buffer to a base64-encoded string
- * @param {Buffer} arrayBuffer - The buffer to convert
- * @returns {string} Base64-encoded string
- */
+
 function bufferToBase64(arrayBuffer) {
     return Buffer.from(arrayBuffer).toString('base64');
 }
 
-/**
- * Converts a base64-encoded string back to a Buffer
- * @param {string} base64 - The base64 string to convert
- * @returns {Buffer} The decoded buffer
- */
 function base64ToBuffer(base64) {
     return Buffer.from(base64, 'base64');
 }
 
-/**
- * Encrypts a message using AES-256-GCM encryption
- * This is required by the UID2 API to protect user data in transit.
- * @param {string|Buffer} message - The message to encrypt (typically user email)
- * @param {string} base64Key - Your UID2 Client Secret (base64-encoded)
- * @returns {Object} Object containing the ciphertext and initialization vector
- */
+// Encrypts data using AES-256-GCM
 function encryptRequest(message, base64Key) {
     const iv = crypto.randomBytes(ivLength);
     const cipher = crypto.createCipheriv(encryptionAlgo, base64ToBuffer(base64Key), iv);
     const ciphertext = Buffer.concat([cipher.update(message), cipher.final(), cipher.getAuthTag()]);
-
-    return { ciphertext: ciphertext, iv: iv };
+    return { ciphertext, iv };
 }
 
-/**
- * Compares two byte arrays for equality
- * Used to verify that the nonce in the response matches the request (prevents tampering)
- * @param {Uint8Array} array1 - First array to compare
- * @param {Uint8Array} array2 - Second array to compare
- * @returns {boolean} True if arrays are equal, false otherwise
- */
+// Compares two byte arrays
 function isEqual(array1, array2) {
     for (let i = 0; i < array1.byteLength; i++) {
         if (array1[i] !== array2[i]) return false;
     }
     return true;
 }
 
-/**
- * Decrypts a response from the UID2 API
- * Verifies the nonce to ensure the response hasn't been tampered with.
- * @param {string} base64Response - The encrypted response from UID2 API
- * @param {string} base64Key - Your UID2 Client Secret (base64-encoded)
- * @param {Buffer} nonceInRequest - The nonce that was sent in the request
- * @returns {Object} The decrypted JSON response containing the UID2 token
- * @throws {Error} If the nonce doesn't match (indicates tampering)
- */
-function decrypt(base64Response, base64Key, nonceInRequest)  {
+// Decrypts UID2 API response and verifies nonce
+function decrypt(base64Response, base64Key, nonceInRequest) {
     const responseBytes = base64ToBuffer(base64Response);
     const iv = responseBytes.subarray(0, ivLength);
 
@@ -110,25 +65,23 @@ function decrypt(base64Response, base64Key, nonceInRequest)  {
     const tag = responseBytes.subarray(responseBytes.length - tagLength);
     decipher.setAuthTag(tag);
 
-    const decrypted = Buffer.concat([decipher.update(responseBytes.subarray(ivLength, responseBytes.length - tagLength)), decipher.final()]);
+    const decrypted = Buffer.concat([
+        decipher.update(responseBytes.subarray(ivLength, responseBytes.length - tagLength)),
+        decipher.final()
+    ]);
 
+    // Verify nonce matches
     const nonceInResponse = decrypted.subarray(timestampLength, timestampLength + nonceLength);
     if (!isEqual(nonceInRequest, new Uint8Array(nonceInResponse))) {
-        throw new Error('Nonce in request does not match nonce in response');
+        throw new Error('Nonce mismatch');
     }
-    const payload = decrypted.subarray(timestampLength + nonceLength);
 
+    const payload = decrypted.subarray(timestampLength + nonceLength);
     const responseString = String.fromCharCode.apply(String, new Uint8Array(payload));
     return JSON.parse(responseString);
 }
 
-/**
- * Creates an encrypted "envelope" to send to the UID2 API
- * The envelope contains: timestamp, nonce, and the payload (user email)
- * This format is required by the UID2 API for all token generation requests.
- * @param {string} payload - The JSON string to encrypt (e.g., '{"email": "user@example.com"}')
- * @returns {Object} Object containing the encrypted envelope and nonce
- */
+// Creates encrypted envelope for UID2 API request
 function createEnvelope(payload) {
     const millisec = BigInt(Date.now());
     const bufferMillisec = new ArrayBuffer(timestampLength);
@@ -140,28 +93,16 @@ function createEnvelope(payload) {
 
     const { ciphertext, iv } = encryptRequest(body, uid2ClientSecret);
 
-    const envelopeVersion =  Buffer.alloc(1, 1);
-    const envelope = bufferToBase64(Buffer.concat([envelopeVersion, iv, Buffer.from( new Uint8Array(ciphertext))]));
-    return { envelope: envelope, nonce: nonce };
+    const envelopeVersion = Buffer.alloc(1, 1);
+    const envelope = bufferToBase64(Buffer.concat([envelopeVersion, iv, Buffer.from(new Uint8Array(ciphertext))]));
+    return { envelope, nonce };
 }
 
 // ============================================================================
-// API ENDPOINT: Token Generation
+// API Endpoint
 // ============================================================================
 
-/**
- * POST /login
- * Generates a UID2 token for the given email address
- * 
- * This endpoint:
- * 1. Receives an email from the front-end
- * 2. Encrypts it and sends to UID2 API's /v2/token/generate endpoint
- * 3. Decrypts the response
- * 4. Returns the UID2 identity (token) as JSON to the front-end
- * 
- * Request body: { email: "user@example.com" }
- * Response: { identity: { advertising_token: "...", refresh_token: "...", ... } }
- */
+// POST /login - Generates UID2 token for email address
 app.post('/login', async (req, res) => {
     const jsonEmail = JSON.stringify({ email: req.body.email });
     const { envelope, nonce } = createEnvelope(jsonEmail);
@@ -179,14 +120,12 @@ app.post('/login', async (req, res) => {
         const response = decrypt(encryptedResponse.data, uid2ClientSecret, nonce);
 
         if (response.status === 'optout') {
-            // Opt-out is a valid state, return 200 with status
             res.json({ status: 'optout' });
         } else if (response.status !== 'success') {
             res.status(400).json({ error: 'Token generation failed', status: response.status });
         } else if (typeof response.body !== 'object') {
             res.status(400).json({ error: 'Unexpected response format' });
         } else {
-            // Return the identity (UID2 token) as JSON
             res.json({ identity: response.body });
         }
     } catch (error) {
@@ -196,9 +135,9 @@ app.post('/login', async (req, res) => {
 });
 
 // ============================================================================
-// START THE SERVER
+// Start Server
 // ============================================================================
+
 app.listen(port, () => {
-  console.log(`UID2 Prebid Client-Server example listening at http://localhost:${port}`);
+    console.log(`UID2 Prebid Client-Server example listening at http://localhost:${port}`);
 });
-