implement auth

.env.example

@@ -1,4 +1,3 @@
-# Example environment variables
 NODE_ENV=development
-UNSPLASH_ACCESS_KEY=your_unsplash_access_key_here
 PORT=8080
+UNSPLASH_ACCESS_KEY=your_unsplash_access_key_here

.gitignore

@@ -40,4 +40,7 @@ coverage/
 .temp/
 
 # db
-*.db
+*.db
+
+# auth private key
+auth_key.pem

.vscode/launch.json

@@ -11,8 +11,6 @@
       ],
       "cwd": "${workspaceFolder}",
       "envFile": "${workspaceFolder}/.env",
-      "console": "integratedTerminal",
-      "internalConsoleOptions": "neverOpen"
     }
   ]
 }

README.md

@@ -5,15 +5,18 @@ A Node.js REST API built with TypeScript and Express.
 ## Getting Started
 
 ### Prerequisites
+
 - Node.js >= 18
 - npm
 
 ### Installation
+
 ```sh
 npm install
 ```
 
 ### Configuration
+
 1. Copy `.env.example` to `.env` and fill in your secrets:
    ```sh
    cp .env.example .env
@@ -21,20 +24,24 @@ npm install
 2. Set your Unsplash access key and other variables in `.env`.
 
 ### Running the Server
+
 ```sh
 npm start
 ```
 
 ### Formatting Code
+
 ```sh
 npm run format
 ```
 
 ### Recommended VS Code Extensions
+
 - ESLint
 - Prettier
 
 ## Project Structure
+
 ```
 kuwot-api-js/
 ├── src/
@@ -54,7 +61,9 @@ kuwot-api-js/
 ```
 
 ## Contributing
+
 Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.
 
 ## License
+
 ISC

package-lock.json

@@ -10,7 +10,8 @@
       "license": "ISC",
       "dependencies": {
         "dotenv": "^17.2.3",
-        "express": "^5.1.0"
+        "express": "^5.1.0",
+        "uuid": "^13.0.0"
       },
       "devDependencies": {
         "@types/express": "^5.0.3",
@@ -2438,6 +2439,19 @@
         "punycode": "^2.1.0"
       }
     },
+    "node_modules/uuid": {
+      "version": "13.0.0",
+      "resolved": "https://registry.npmjs.org/uuid/-/uuid-13.0.0.tgz",
+      "integrity": "sha512-XQegIaBTVUjSHliKqcnFqYypAd4S+WCYt5NIeRs6w/UAry7z8Y9j5ZwRRL4kzq9U3sD6v+85er9FvkEaBpji2w==",
+      "funding": [
+        "https://github.com/sponsors/broofa",
+        "https://github.com/sponsors/ctavan"
+      ],
+      "license": "MIT",
+      "bin": {
+        "uuid": "dist-node/bin/uuid"
+      }
+    },
     "node_modules/v8-compile-cache-lib": {
       "version": "3.0.1",
       "resolved": "https://registry.npmjs.org/v8-compile-cache-lib/-/v8-compile-cache-lib-3.0.1.tgz",

package.json

@@ -14,7 +14,8 @@
   "license": "ISC",
   "dependencies": {
     "dotenv": "^17.2.3",
-    "express": "^5.1.0"
+    "express": "^5.1.0",
+    "uuid": "^13.0.0"
   },
   "devDependencies": {
     "@types/express": "^5.0.3",

src/auth.ts

@@ -0,0 +1,40 @@
+import { constants, createPrivateKey, privateDecrypt } from 'crypto';
+import * as fs from 'fs';
+import { validate as validateUUID } from 'uuid';
+
+/**
+ * Simple auth implementation using RSA.
+ * Client sends a base64 UUID encrypted with public key, server decrypts with private key and checks validity.
+ */
+export class Auth {
+  constructor() {}
+
+  decryptToken(token: string): string {
+    const keyPem = fs.readFileSync('auth_key.pem', 'utf-8');
+    const privateKey = createPrivateKey({ key: keyPem, format: 'pem' });
+    const encryptedBuffer = Buffer.from(token, 'base64');
+    const decrypted = privateDecrypt(
+      {
+        key: privateKey,
+        padding: constants.RSA_PKCS1_PADDING,
+      },
+      encryptedBuffer
+    );
+    return decrypted.toString('utf-8');
+  }
+
+  isTokenValid(decryptedToken: string): boolean {
+    return validateUUID(decryptedToken);
+  }
+
+  isTokenExpired(issuedAt: number): boolean {
+    const tokenLifetimeSeconds = 300;
+    const allowedDriftSeconds = 10;
+    const now = Math.floor(Date.now() / 1000); // current unix timestamp in seconds
+    const diff = now - issuedAt;
+    return (
+      diff < -allowedDriftSeconds ||
+      diff > tokenLifetimeSeconds + allowedDriftSeconds
+    );
+  }
+}

src/authMiddleware.ts

@@ -0,0 +1,40 @@
+import type { NextFunction, Request, Response } from 'express';
+import { Auth } from './auth.js';
+import { AuthPayload } from './types.js';
+
+const auth = new Auth();
+
+export function bearerAuthMiddleware(
+  req: Request,
+  res: Response,
+  next: NextFunction
+) {
+  const authHeader = req.headers['authorization'];
+  if (!authHeader || !authHeader.startsWith('Bearer ')) {
+    return res
+      .status(401)
+      .json({ error: 'Missing or invalid Authorization header' });
+  }
+
+  try {
+    const token = authHeader.substring('Bearer '.length);
+    const decrypted = auth.decryptToken(token);
+    if (!decrypted) {
+      return res.status(401).json({ error: 'Invalid token' });
+    }
+
+    const payload: AuthPayload = JSON.parse(decrypted);
+    if (!payload.token || typeof payload.issuedAt !== 'number') {
+      return res.status(401).json({ error: 'Token payload missing fields' });
+    }
+    if (!auth.isTokenValid(payload.token)) {
+      return res.status(401).json({ error: 'Token is not a valid UUID' });
+    }
+    if (auth.isTokenExpired(payload.issuedAt)) {
+      return res.status(401).json({ error: 'Token expired' });
+    }
+    next();
+  } catch (e) {
+    return res.status(500).json({ error: (e as Error).message });
+  }
+}

src/index.ts

@@ -1,5 +1,6 @@
 import 'dotenv/config';
 import express from 'express';
+import { bearerAuthMiddleware } from './authMiddleware.js';
 import {
   onGetImages,
   onGetQuoteById,
@@ -9,6 +10,8 @@ import {
 
 const app = express();
 
+app.use(bearerAuthMiddleware);
+
 app.get('/quotes/random', onGetRandomQuote);
 app.get('/quotes/:id', onGetQuoteById);
 app.get('/translations', onGetTranslations);

src/routes.ts

@@ -22,8 +22,8 @@ function onGetQuoteById(req: Request, res: Response): void {
     const id = parseInt(idParam);
     const quote = getQuote(id);
     res.status(200).send(quote);
-  } catch (error: any) {
-    res.status(500).send({ error: error.message });
+  } catch (e) {
+    res.status(500).send({ error: (e as Error).message });
   }
 }
 
@@ -31,8 +31,8 @@ function onGetTranslations(_req: Request, res: Response): void {
   try {
     const translations = listTranslations();
     res.status(200).send(translations);
-  } catch (error: any) {
-    res.status(500).send({ error: error.message });
+  } catch (e) {
+    res.status(500).send({ error: (e as Error).message });
   }
 }
 
@@ -40,8 +40,8 @@ async function onGetImages(_req: Request, res: Response): Promise<void> {
   try {
     const images = await listRandomImages();
     res.status(200).send(images);
-  } catch (error: any) {
-    res.status(500).send({ error: error.message });
+  } catch (e) {
+    res.status(500).send({ error: (e as Error).message });
   }
 }
 

src/types.d.ts

@@ -1,3 +1,12 @@
+export interface AuthPayload {
+  // An UUID string, unique per request.
+  token: string;
+
+  // Unix time in seconds. It is the time when the token was issued.
+  // Will expire after a time window.
+  issuedAt: number;
+}
+
 export interface Quote {
   id: number;
   text: string;

tsconfig.json

@@ -8,6 +8,7 @@
     "forceConsistentCasingInFileNames": true,
     "strict": true,
     "skipLibCheck": true,
+    "sourceMap": true,
     "outDir": "./dist",
     "rootDir": "./src"
   },