Implement explicit cache control configuration

packages/api/config/signed-api.example.json

@@ -10,8 +10,5 @@
     }
   ],
   "allowedAirnodes": ["0x8A791620dd6260079BF849Dc5567aDC3F2FdC318"],
-  "maxBatchSize": 10,
-  "cache": {
-    "maxAgeSeconds": 300
-  }
+  "maxBatchSize": 10
 }

packages/api/src/handlers.test.ts

@@ -174,8 +174,6 @@ describe(getData.name, () => {
       headers: {
         'access-control-allow-methods': '*',
         'access-control-allow-origin': '*',
-        'cache-control': 'no-store',
-        'cdn-cache-control': 'max-age=10',
         'content-type': 'application/json',
       },
       statusCode: 200,
@@ -203,8 +201,6 @@ describe(getData.name, () => {
       headers: {
         'access-control-allow-methods': '*',
         'access-control-allow-origin': '*',
-        'cache-control': 'no-store',
-        'cdn-cache-control': 'max-age=10',
         'content-type': 'application/json',
       },
       statusCode: 200,
@@ -228,8 +224,6 @@ describe(listAirnodeAddresses.name, () => {
       headers: {
         'access-control-allow-methods': '*',
         'access-control-allow-origin': '*',
-        'cache-control': 'no-store',
-        'cdn-cache-control': 'max-age=300',
         'content-type': 'application/json',
       },
       statusCode: 200,

packages/api/src/handlers.ts

@@ -2,8 +2,8 @@ import { go, goSync } from '@api3/promise-utils';
 import { isEmpty, isNil, omit, size } from 'lodash';
 
 import { getConfig } from './config';
-import { CACHE_HEADERS, COMMON_HEADERS } from './constants';
 import { deriveBeaconId, recoverSignerAddress } from './evm';
+import { createResponseHeaders } from './headers';
 import { get, getAll, getAllAirnodeAddresses, prune, putAll } from './in-memory-cache';
 import { logger } from './logger';
 import { type SignedData, batchSignedDataSchema, evmAddressSchema } from './schema';
@@ -112,7 +112,7 @@ export const batchInsertData = async (requestBody: unknown): Promise<ApiResponse
 
   return {
     statusCode: 201,
-    headers: COMMON_HEADERS,
+    headers: createResponseHeaders(getConfig().cache),
     body: JSON.stringify({
       count: newSignedData.length,
       skipped: batchSignedData.length - newSignedData.length,
@@ -148,7 +148,7 @@ export const getData = async (airnodeAddress: string, delaySeconds: number): Pro
 
   return {
     statusCode: 200,
-    headers: { ...COMMON_HEADERS, ...CACHE_HEADERS },
+    headers: createResponseHeaders(getConfig().cache),
     body: JSON.stringify({ count: goReadDb.data.length, data }),
   };
 };
@@ -165,7 +165,7 @@ export const listAirnodeAddresses = async (): Promise<ApiResponse> => {
 
   return {
     statusCode: 200,
-    headers: { ...COMMON_HEADERS, ...CACHE_HEADERS, 'cdn-cache-control': `max-age=${getConfig().cache.maxAgeSeconds}` },
+    headers: createResponseHeaders(getConfig().cache),
     body: JSON.stringify({ count: airnodeAddresses.length, 'available-airnodes': airnodeAddresses }),
   };
 };

packages/api/src/headers.test.ts

@@ -0,0 +1,43 @@
+import { createResponseHeaders } from './headers';
+
+describe(createResponseHeaders.name, () => {
+  it('returns common headers when cache is not set', () => {
+    const expectedHeaders = {
+      'content-type': 'application/json',
+      'access-control-allow-origin': '*',
+      'access-control-allow-methods': '*',
+    };
+    expect(createResponseHeaders()).toStrictEqual(expectedHeaders);
+  });
+
+  it('returns browser cache headers when cache type is browser', () => {
+    const expectedHeaders = {
+      'content-type': 'application/json',
+      'access-control-allow-origin': '*',
+      'access-control-allow-methods': '*',
+      'cache-control': 'max-age=3600',
+    };
+    expect(
+      createResponseHeaders({
+        type: 'browser',
+        maxAgeSeconds: 3600,
+      })
+    ).toStrictEqual(expectedHeaders);
+  });
+
+  it('returns CDN cache headers when cache type is cdn', () => {
+    const expectedHeaders = {
+      'content-type': 'application/json',
+      'access-control-allow-origin': '*',
+      'access-control-allow-methods': '*',
+      'cache-control': 'no-store',
+      'cdn-cache-control': 'max-age=3600',
+    };
+    expect(
+      createResponseHeaders({
+        type: 'cdn',
+        maxAgeSeconds: 3600,
+      })
+    ).toStrictEqual(expectedHeaders);
+  });
+});

packages/api/src/headers.ts

@@ -0,0 +1,28 @@
+import type { Cache } from './schema';
+
+const COMMON_HEADERS = {
+  'content-type': 'application/json',
+  'access-control-allow-origin': '*',
+  'access-control-allow-methods': '*',
+};
+
+export const createResponseHeaders = (cache?: Cache | undefined) => {
+  if (!cache) return COMMON_HEADERS;
+
+  const { type, maxAgeSeconds } = cache;
+  switch (type) {
+    case 'browser': {
+      return {
+        ...COMMON_HEADERS,
+        'cache-control': `max-age=${maxAgeSeconds}`,
+      };
+    }
+    case 'cdn': {
+      return {
+        ...COMMON_HEADERS,
+        'cache-control': 'no-store', // Disable browser-caching
+        'cdn-cache-control': `max-age=${maxAgeSeconds}`,
+      };
+    }
+  }
+};

packages/api/src/schema.ts

@@ -24,12 +24,17 @@ export const endpointsSchema = z
 
 export const allowedAirnodesSchema = z.union([z.literal('*'), z.array(evmAddressSchema).nonempty()]);
 
+export const cacheSchema = z.strictObject({
+  type: z.union([z.literal('browser'), z.literal('cdn')]),
+  maxAgeSeconds: z.number().nonnegative().int(),
+});
+
+export type Cache = z.infer<typeof cacheSchema>;
+
 export const configSchema = z.strictObject({
   endpoints: endpointsSchema,
   maxBatchSize: z.number().nonnegative().int(),
-  cache: z.strictObject({
-    maxAgeSeconds: z.number().nonnegative().int(),
-  }),
+  cache: cacheSchema.optional(),
   allowedAirnodes: allowedAirnodesSchema,
 });
 

packages/api/src/utils.ts

@@ -1,4 +1,4 @@
-import { COMMON_HEADERS } from './constants';
+import { createResponseHeaders } from './headers';
 import type { BatchSignedData, SignedData } from './schema';
 import type { ApiResponse } from './types';
 
@@ -18,5 +18,5 @@ export const generateErrorResponse = (
   detail?: string,
   extra?: unknown
 ): ApiResponse => {
-  return { statusCode, headers: COMMON_HEADERS, body: JSON.stringify({ message, detail, extra }) };
+  return { statusCode, headers: createResponseHeaders(), body: JSON.stringify({ message, detail, extra }) };
 };

packages/e2e/src/signed-api/signed-api.json

@@ -10,8 +10,5 @@
     }
   ],
   "maxBatchSize": 10,
-  "cache": {
-    "maxAgeSeconds": 0
-  },
   "allowedAirnodes": ["0xbF3137b0a7574563a23a8fC8badC6537F98197CC"]
 }