Improve caching support

src/controllers/cdnController.js

@@ -70,9 +70,9 @@ export const proxyReportsFile = async (req, res, filePath) => {
         // Set response headers
         res.setHeader('Content-Type', contentType);
         res.setHeader('Cross-Origin-Resource-Policy', 'cross-origin');
-        res.setHeader('Cloud-CDN-Cache-Tag', 'bucket-proxy');
-        // Browser cache: 1 hour, CDN cache: 30 days
-        res.setHeader('Cache-Control', 'public, max-age=3600, s-maxage=2592000');
+        res.setHeader('Cache-Tag', 'bucket-proxy');
+        // Browser cache: 1 hour, CDN cache: 1 days
+        res.setHeader('Cache-Control', 'public, max-age=3600, s-maxage=86400');
 
         if (metadata.etag) {
             res.setHeader('ETag', metadata.etag);

src/controllers/reportController.js

@@ -7,7 +7,9 @@ import {
     sendValidationError,
     getLatestDate,
     handleControllerError,
-    validateArrayParameter
+    validateArrayParameter,
+    generateETag,
+    isModified
 } from '../utils/controllerHelpers.js';
 
 /**
@@ -123,9 +125,17 @@ const createReportController = (reportType, { crossGeo = false } = {}) => {
                 data.push(doc.data());
             });
 
-            // Send response
+            // Send response with ETag support
+            const jsonData = JSON.stringify(data);
+            const etag = generateETag(jsonData);
+            res.setHeader('ETag', `"${etag}"`);
+            if (!isModified(req, etag)) {
+                res.statusCode = 304;
+                res.end();
+                return;
+            }
             res.statusCode = 200;
-            res.end(JSON.stringify(data));
+            res.end(jsonData);
 
         } catch (error) {
             handleControllerError(res, error, `fetching ${reportType} data`);

src/index.js

@@ -1,5 +1,5 @@
-import crypto from 'crypto';
 import functions from '@google-cloud/functions-framework';
+import { sendJSONResponse, isModified } from './utils/controllerHelpers.js';
 
 // Dynamic imports for better performance - only load when needed
 const controllers = {
@@ -67,33 +67,12 @@ const setCORSHeaders = (res) => {
 const setCommonHeaders = (res) => {
   setCORSHeaders(res);
   res.setHeader('Content-Type', 'application/json');
-  // Browser cache: 1 hour, CDN cache: 30 days
-  res.setHeader('Cache-Control', 'public, max-age=3600, s-maxage=2592000');
-  res.setHeader('Cloud-CDN-Cache-Tag', 'report-api');
+  // Browser cache: 1 hour, CDN cache: 1 day
+  res.setHeader('Cache-Control', 'public, max-age=3600, s-maxage=86400');
+  res.setHeader('Cache-Tag', 'report-api');
   res.setHeader('Timing-Allow-Origin', '*');
 };
 
-// Helper function to generate ETag
-const generateETag = (jsonData) => {
-  return crypto.createHash('md5').update(jsonData).digest('hex');
-};
-
-// Helper function to send JSON response with ETag support
-const sendJSONResponse = (res, data, statusCode = 200) => {
-  const jsonData = JSON.stringify(data);
-  const etag = generateETag(jsonData);
-
-  res.setHeader('ETag', `"${etag}"`);
-  res.statusCode = statusCode;
-  res.end(jsonData);
-};
-
-// Helper function to check if resource is modified
-const isModified = (req, etag) => {
-  const ifNoneMatch = req.headers['if-none-match'] || (req.get && req.get('if-none-match'));
-  return !ifNoneMatch || ifNoneMatch !== `"${etag}"`;
-};
-
 // Route handler function
 const handleRequest = async (req, res) => {
   try {

src/tests/headers.test.js

@@ -12,8 +12,8 @@ jest.unstable_mockModule('../controllers/cdnController.js', () => ({
     proxyReportsFile: jest.fn((req, res) => {
         res.setHeader('Content-Type', 'application/json');
         res.setHeader('Cross-Origin-Resource-Policy', 'cross-origin');
-        res.setHeader('Cloud-CDN-Cache-Tag', 'bucket-proxy');
-        res.setHeader('Cache-Control', 'public, max-age=3600, s-maxage=2592000');
+        res.setHeader('Cache-Tag', 'bucket-proxy');
+        res.setHeader('Cache-Control', 'public, max-age=3600, s-maxage=86400');
         res.statusCode = 200;
         res.end(JSON.stringify({ mocked: true }));
     })
@@ -34,8 +34,8 @@ describe('CDN Headers', () => {
         const res = await request(app).get('/v1/technologies');
 
         expect(res.statusCode).toEqual(200);
-        expect(res.headers['cache-control']).toBe('public, max-age=3600, s-maxage=2592000');
-        expect(res.headers['cloud-cdn-cache-tag']).toBe('report-api');
+        expect(res.headers['cache-control']).toBe('public, max-age=3600, s-maxage=86400');
+        expect(res.headers['cache-tag']).toBe('report-api');
         expect(res.headers['access-control-allow-origin']).toBe('*');
         expect(res.headers['access-control-allow-headers']).toContain('Content-Type');
         expect(res.headers['access-control-allow-headers']).toContain('If-None-Match');
@@ -46,16 +46,16 @@ describe('CDN Headers', () => {
         const res = await request(app).get('/v1/static/test.json');
 
         expect(res.statusCode).toEqual(200);
-        expect(res.headers['cache-control']).toBe('public, max-age=3600, s-maxage=2592000');
-        expect(res.headers['cloud-cdn-cache-tag']).toBe('bucket-proxy');
+        expect(res.headers['cache-control']).toBe('public, max-age=3600, s-maxage=86400');
+        expect(res.headers['cache-tag']).toBe('bucket-proxy');
         expect(res.headers['cross-origin-resource-policy']).toBe('cross-origin');
     });
 
     it('should set correct headers for health check', async () => {
         const res = await request(app).get('/');
 
         expect(res.statusCode).toEqual(200);
-        expect(res.headers['cache-control']).toBe('public, max-age=3600, s-maxage=2592000');
-        expect(res.headers['cloud-cdn-cache-tag']).toBe('report-api');
+        expect(res.headers['cache-control']).toBe('public, max-age=3600, s-maxage=86400');
+        expect(res.headers['cache-tag']).toBe('report-api');
     });
 });

src/tests/routes.test.js

@@ -455,6 +455,50 @@ describe('API Routes', () => {
       expect(res.headers).toHaveProperty('etag');
     });
 
+    it('should include ETag headers on executeQuery-based routes', async () => {
+      const res = await request(app).get('/v1/technologies');
+      expect(res.statusCode).toEqual(200);
+      expect(res.headers).toHaveProperty('etag');
+      expect(res.headers['etag']).toMatch(/^"[a-f0-9]+"$/);
+    });
+
+    it('should include ETag headers on reportController-based routes', async () => {
+      const res = await request(app).get('/v1/adoption');
+      expect(res.statusCode).toEqual(200);
+      expect(res.headers).toHaveProperty('etag');
+      expect(res.headers['etag']).toMatch(/^"[a-f0-9]+"$/);
+    });
+
+    it('should return 304 for executeQuery-based routes when ETag matches', async () => {
+      const first = await request(app).get('/v1/technologies');
+      expect(first.statusCode).toEqual(200);
+      const etag = first.headers['etag'];
+
+      const second = await request(app)
+        .get('/v1/technologies')
+        .set('If-None-Match', etag);
+      expect(second.statusCode).toEqual(304);
+    });
+
+    it('should return 304 for reportController-based routes when ETag matches', async () => {
+      const first = await request(app).get('/v1/adoption');
+      expect(first.statusCode).toEqual(200);
+      const etag = first.headers['etag'];
+
+      const second = await request(app)
+        .get('/v1/adoption')
+        .set('If-None-Match', etag);
+      expect(second.statusCode).toEqual(304);
+    });
+
+    it('should return 200 when If-None-Match does not match', async () => {
+      const res = await request(app)
+        .get('/v1/technologies')
+        .set('If-None-Match', '"stale-etag"');
+      expect(res.statusCode).toEqual(200);
+      expect(res.headers).toHaveProperty('etag');
+    });
+
     it('should include timing headers', async () => {
       const res = await request(app).get('/v1/technologies');
       expect(res.headers['timing-allow-origin']).toEqual('*');

src/utils/controllerHelpers.js

@@ -1,3 +1,4 @@
+import crypto from 'crypto';
 import { convertToArray } from './helpers.js';
 
 /**
@@ -99,6 +100,23 @@ const handleControllerError = (res, error, operation) => {
   }));
 };
 
+const generateETag = (jsonData) => {
+  return crypto.createHash('md5').update(jsonData).digest('hex');
+};
+
+const sendJSONResponse = (res, data, statusCode = 200) => {
+  const jsonData = JSON.stringify(data);
+  const etag = generateETag(jsonData);
+  res.setHeader('ETag', `"${etag}"`);
+  res.statusCode = statusCode;
+  res.end(jsonData);
+};
+
+const isModified = (req, etag) => {
+  const ifNoneMatch = req.headers['if-none-match'] || (req.get && req.get('if-none-match'));
+  return !ifNoneMatch || ifNoneMatch !== `"${etag}"`;
+};
+
 /**
  * Generic query executor
  * Handles query execution and response for simple queries
@@ -126,9 +144,17 @@ const executeQuery = async (req, res, collection, queryBuilder, dataProcessor =
       data = dataProcessor(data, params);
     }
 
-    // Send response
+    // Send response with ETag support
+    const jsonData = JSON.stringify(data);
+    const etag = generateETag(jsonData);
+    res.setHeader('ETag', `"${etag}"`);
+    if (!isModified(req, etag)) {
+      res.statusCode = 304;
+      res.end();
+      return;
+    }
     res.statusCode = 200;
-    res.end(JSON.stringify(data));
+    res.end(jsonData);
 
   } catch (error) {
     // Handle validation errors specifically
@@ -170,5 +196,8 @@ export {
   validateArrayParameter,
   handleControllerError,
   executeQuery,
-  validateTechnologyArray
+  validateTechnologyArray,
+  generateETag,
+  sendJSONResponse,
+  isModified
 };