feat: implement real-time exchange rates service with multi-source integration, caching, historical data, alerts, WebSocket, and background jobs

package.json

@@ -1,80 +1,85 @@
 {
-  "name": "chainremit_backend",
-  "version": "1.0.0",
-  "description": "",
-  "main": "dist/app.js",
-  "scripts": {
-    "dev": "nodemon src/app.ts",
-    "build": "tsc",
-    "start": "node dist/app.js",
-    "test": "jest",
-    "test:watch": "jest --watch",
-    "test:coverage": "jest --coverage",
-    "lint": "eslint src --ext .ts",
-    "lint:fix": "eslint src --ext .ts --fix",
-    "format": "prettier --write \"src/**/*.ts\"",
-    "prepare": "husky install"
-  },
-  "repository": {
-    "type": "git",
-    "url": "https://github.com/MetroLogic/chainremit_backend.git"
-  },
-  "keywords": [],
-  "author": "",
-  "license": "ISC",
-  "bugs": {
-    "url": "https://github.com/MetroLogic/chainremit_backend.git/issues"
-  },
-  "homepage": "https://github.com/MetroLogic/chainremit_backend.git#readme",
-  "dependencies": {
-    "bcrypt": "^6.0.0",
-    "compression": "^1.7.4",
-    "cors": "^2.8.5",
-    "dotenv": "^16.0.3",
-    "express": "^4.18.2",
-    "express-rate-limit": "^8.0.1",
-    "google-auth-library": "^10.1.0",
-    "helmet": "^6.1.5",
-    "joi": "^17.13.3",
-    "jsonwebtoken": "^9.0.2",
-    "morgan": "^1.10.0",
-    "swagger-jsdoc": "^6.2.8",
-    "swagger-ui-express": "^5.0.1",
-    "typescript": "^5.0.0",
-    "winston": "^3.17.0"
-  },
-  "devDependencies": {
-    "@eslint/js": "^9.32.0",
-    "@types/bcrypt": "^6.0.0",
-    "@types/compression": "^1.8.1",
-    "@types/cors": "^2.8.19",
-    "@types/express": "^4.17.17",
-    "@types/jest": "^29.5.0",
-    "@types/jsonwebtoken": "^9.0.10",
-    "@types/morgan": "^1.9.10",
-    "@types/node": "^20.0.0",
-    "@types/swagger-jsdoc": "^6.0.4",
-    "@types/swagger-ui-express": "^4.1.8",
-    "@types/winston": "^2.4.4",
-    "@typescript-eslint/eslint-plugin": "^8.38.0",
-    "eslint": "^8.57.1",
-    "eslint-config-prettier": "^10.1.8",
-    "eslint-plugin-prettier": "^5.5.3",
-    "globals": "^16.3.0",
-    "husky": "^8.0.3",
-    "jest": "^29.5.0",
-    "jiti": "^2.5.1",
-    "lint-staged": "^16.1.2",
-    "nodemon": "^3.1.10",
-    "prettier": "^3.6.2",
-    "ts-jest": "^29.4.0",
-    "ts-node": "^10.9.1",
-    "typescript-eslint": "^8.38.0"
-  },
-  "lint-staged": {
-    "src/**/*.ts": [
-      "eslint --fix",
-      "prettier --write"
-    ]
-  }
+    "name": "chainremit_backend",
+    "version": "1.0.0",
+    "description": "",
+    "main": "dist/app.js",
+    "scripts": {
+        "dev": "nodemon src/app.ts",
+        "build": "tsc",
+        "start": "node dist/app.js",
+        "test": "jest",
+        "test:watch": "jest --watch",
+        "test:coverage": "jest --coverage",
+        "lint": "eslint src --ext .ts",
+        "lint:fix": "eslint src --ext .ts --fix",
+        "format": "prettier --write \"src/**/*.ts\"",
+        "prepare": "husky install"
+    },
+    "repository": {
+        "type": "git",
+        "url": "https://github.com/MetroLogic/chainremit_backend.git"
+    },
+    "keywords": [],
+    "author": "",
+    "license": "ISC",
+    "bugs": {
+        "url": "https://github.com/MetroLogic/chainremit_backend.git/issues"
+    },
+    "homepage": "https://github.com/MetroLogic/chainremit_backend.git#readme",
+    "dependencies": {
+        "axios": "^1.7.0",
+        "bcrypt": "^6.0.0",
+        "bull": "^4.10.4",
+        "compression": "^1.7.4",
+        "cors": "^2.8.5",
+        "dotenv": "^16.0.3",
+        "express": "^4.18.2",
+        "express-rate-limit": "^8.0.1",
+        "google-auth-library": "^10.1.0",
+        "helmet": "^6.1.5",
+        "ioredis": "^5.3.2",
+        "joi": "^17.13.3",
+        "jsonwebtoken": "^9.0.2",
+        "morgan": "^1.10.0",
+        "swagger-jsdoc": "^6.2.8",
+        "swagger-ui-express": "^5.0.1",
+        "typescript": "^5.0.0",
+        "winston": "^3.17.0",
+        "ws": "^8.15.0"
+    },
+    "devDependencies": {
+        "@eslint/js": "^9.32.0",
+        "@types/bcrypt": "^6.0.0",
+        "@types/compression": "^1.8.1",
+        "@types/cors": "^2.8.19",
+        "@types/express": "^4.17.17",
+        "@types/jest": "^29.5.0",
+        "@types/jsonwebtoken": "^9.0.10",
+        "@types/morgan": "^1.9.10",
+        "@types/node": "^20.0.0",
+        "@types/swagger-jsdoc": "^6.0.4",
+        "@types/swagger-ui-express": "^4.1.8",
+        "@types/winston": "^2.4.4",
+        "@types/ws": "^8.18.1",
+        "@typescript-eslint/eslint-plugin": "^8.38.0",
+        "eslint": "^8.57.1",
+        "eslint-config-prettier": "^10.1.8",
+        "eslint-plugin-prettier": "^5.5.3",
+        "globals": "^16.3.0",
+        "husky": "^8.0.3",
+        "jest": "^29.5.0",
+        "jiti": "^2.5.1",
+        "lint-staged": "^16.1.2",
+        "nodemon": "^3.1.10",
+        "prettier": "^3.6.2",
+        "ts-jest": "^29.4.0",
+        "ts-node": "^10.9.1",
+        "typescript-eslint": "^8.38.0"
+    },
+    "lint-staged": {
+        "src/**/*.ts": [
+            "eslint --fix",
+            "prettier --write"
+        ]
+    }
 }

src/app.ts

@@ -8,6 +8,10 @@ import logger from './utils/logger';
 import { setupSwagger } from './swagger';
 import authRouter from '../src/router/auth.router';
 
+import ratesRouter from '../src/router/rates.router';
+
+import { scheduleRatesJob } from '../src/jobs/rates.job';
+
 // Load environment variables
 const env = process.env.NODE_ENV || 'development';
 dotenv.config({ path: `.env.${env}` });
@@ -31,6 +35,7 @@ app.use(express.json());
 setupSwagger(app);
 
 app.use('/auth', authRouter);
+app.use('/api/rates', ratesRouter);
 
 // Health check endpoint
 app.get('/health', (_req, res) => {
@@ -45,8 +50,13 @@ app.use((err: Error, _req: express.Request, res: express.Response) => {
 
 const PORT = process.env.PORT || 3000;
 if (process.env.NODE_ENV !== 'test') {
-    app.listen(PORT, () => {
+    const server = app.listen(PORT, () => {
         logger.info(`Server running on port ${PORT}`);
+        scheduleRatesJob();
+    });
+    // WebSocket setup
+    import('../src/ws/rates.ws').then(({ setupRatesWebSocket }) => {
+        setupRatesWebSocket(server);
     });
 }
 

src/config/redis.ts

@@ -0,0 +1,9 @@
+import Redis from 'ioredis';
+
+const redis = new Redis({
+    host: process.env.REDIS_HOST || '127.0.0.1',
+    port: Number(process.env.REDIS_PORT) || 6379,
+    password: process.env.REDIS_PASSWORD || undefined,
+});
+
+export default redis;

src/controller/rates.controller.ts

@@ -0,0 +1,52 @@
+import { Request, Response } from 'express';
+import { RatesService } from '../services/rates.service';
+import Joi from 'joi';
+
+export class RatesController {
+    static async getCurrentRates(req: Request, res: Response) {
+        try {
+            const cached = await RatesService.getCachedRates();
+            if (cached) return res.json(cached);
+            const rates = await RatesService.fetchCurrentRates();
+            await RatesService.cacheRates(rates);
+            return res.json(rates);
+        } catch (err) {
+            return res.status(500).json({ error: 'Failed to fetch current rates' });
+        }
+    }
+
+    static async getHistoricalRates(req: Request, res: Response) {
+        try {
+            const historical = await RatesService.getHistoricalRates();
+            return res.json(historical);
+        } catch (err) {
+            return res.status(500).json({ error: 'Failed to fetch historical rates' });
+        }
+    }
+
+    static async postPriceAlert(req: Request, res: Response) {
+        const schema = Joi.object({
+            symbol: Joi.string().required(),
+            targetPrice: Joi.number().required(),
+            direction: Joi.string().valid('above', 'below').required(),
+            userId: Joi.string().required(),
+        });
+        const { error, value } = schema.validate(req.body);
+        if (error) return res.status(400).json({ error: error.details[0].message });
+        try {
+            await RatesService.setPriceAlert({ ...value, createdAt: Date.now() });
+            return res.status(201).json({ success: true });
+        } catch (err) {
+            return res.status(500).json({ error: 'Failed to set price alert' });
+        }
+    }
+
+    static async getSupportedCurrencies(req: Request, res: Response) {
+        try {
+            const currencies = await RatesService.getSupportedCurrencies();
+            return res.json(currencies);
+        } catch (err) {
+            return res.status(500).json({ error: 'Failed to fetch supported currencies' });
+        }
+    }
+}

src/jobs/rates.job.ts

@@ -0,0 +1,23 @@
+import Bull from 'bull';
+import { RatesService } from '../services/rates.service';
+
+const ratesQueue = new Bull('rates-update', {
+    redis: {
+        host: process.env.REDIS_HOST || '127.0.0.1',
+        port: Number(process.env.REDIS_PORT) || 6379,
+        password: process.env.REDIS_PASSWORD || undefined,
+    },
+});
+
+ratesQueue.process(async () => {
+    const rates = await RatesService.fetchCurrentRates();
+    await RatesService.cacheRates(rates);
+    await RatesService.storeHistoricalRates(rates);
+});
+
+export function scheduleRatesJob() {
+    // Every minute
+    ratesQueue.add({}, { repeat: { cron: '* * * * *' } });
+}
+
+export default ratesQueue;

src/model/rates.model.ts

@@ -0,0 +1,19 @@
+export interface Rate {
+    symbol: string;
+    price: number;
+    currency: string;
+    timestamp: number;
+}
+
+export interface HistoricalRate {
+    timestamp: number;
+    rates: Rate[];
+}
+
+export interface PriceAlert {
+    symbol: string;
+    targetPrice: number;
+    direction: 'above' | 'below';
+    userId: string;
+    createdAt: number;
+}

src/router/rates.router.ts

@@ -0,0 +1,11 @@
+import { Router } from 'express';
+import { RatesController } from '../controller/rates.controller';
+
+const router = Router();
+
+router.get('/current', RatesController.getCurrentRates);
+router.get('/historical', RatesController.getHistoricalRates);
+router.post('/alerts', RatesController.postPriceAlert);
+router.get('/supported-currencies', RatesController.getSupportedCurrencies);
+
+export default router;