feat: add 60s caching to api

apps/api/package.json

@@ -17,15 +17,16 @@
         "test:cov": "vitest run --config vitest.config.ts --coverage"
     },
     "dependencies": {
+        "@zkchainhub/chain-providers": "workspace:*",
         "@zkchainhub/metrics": "workspace:*",
         "@zkchainhub/pricing": "workspace:*",
-        "@zkchainhub/chain-providers": "workspace:*",
         "@zkchainhub/shared": "workspace:*",
         "bignumber.js": "9.1.2",
         "cache-manager": "5.7.6",
         "cors": "2.8.5",
         "dotenv": "16.4.5",
         "express": "4.19.2",
+        "node-cache": "5.1.2",
         "swagger-ui-express": "5.0.1",
         "viem": "2.19.6",
         "yaml": "2.5.0",

apps/api/src/common/middleware/cache.middleware.ts

@@ -0,0 +1,36 @@
+import { NextFunction, Request, Response } from "express";
+import NodeCache from "node-cache";
+
+const DEFAULT_TTL = 60; // 1 minute
+const cache = new NodeCache();
+
+//FIXME: This is a temporary cache implementation. It is not recommended for production use.
+// might be replaced with a more robust solution in the future.
+/**
+ * A middleware that caches responses for a given time to live (TTL).
+ * @param args - The time to live (TTL) in seconds for the cached response.
+ * @returns A middleware function that caches responses for a given time to live (TTL).
+ */
+export function cacheMiddleware(args: { ttl: number } = { ttl: DEFAULT_TTL }) {
+    return async (req: Request, res: Response, next: NextFunction): Promise<void> => {
+        const key = req.originalUrl || req.url;
+        const cachedResponse = await cache.get(key);
+        if (cachedResponse) {
+            // Check if the cached response is a JSON object or plain text
+            res.json(cachedResponse);
+        } else {
+            // Store the original send and json functions
+            const originalJson = res.json.bind(res);
+            // Override the json function
+
+            res.json = (body): Response => {
+                // Cache the response body
+                cache.set(key, body, args.ttl);
+                // Call the original json function with the response body
+                return originalJson(body);
+            };
+
+            next();
+        }
+    };
+}

apps/api/src/metrics/routes/index.ts

@@ -2,6 +2,7 @@ import { z } from "zod";
 
 import { ILogger } from "@zkchainhub/shared";
 
+import { cacheMiddleware } from "../../common/middleware/cache.middleware.js";
 import { BaseRouter } from "../../common/routes/baseRouter.js";
 import { ChainNotFound, MetricsController } from "../index.js";
 
@@ -27,7 +28,7 @@ export class MetricsRouter extends BaseRouter {
          * Retrieves the ecosystem information.
          * @returns {Promise<EcosystemInfo>} The ecosystem information.
          */
-        this.router.get("/ecosystem", async (_req, res, next) => {
+        this.router.get("/ecosystem", cacheMiddleware(), async (_req, res, next) => {
             try {
                 const data = await this.metricsController.getEcosystem();
                 res.json(data);
@@ -42,7 +43,7 @@ export class MetricsRouter extends BaseRouter {
          * @param {number} chainId - The ID of the chain.
          * @returns {Promise<ZKChainInfo>} The chain information.
          */
-        this.router.get("/zkchain/:chainId", async (req, res, next) => {
+        this.router.get("/zkchain/:chainId", cacheMiddleware(), async (req, res, next) => {
             try {
                 const { params } = ChainIdSchema.parse(req);