Topic/k1ch/ internal caching for GET:/jwks.json

server/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@dmgt-tech/the-usher-server",
-  "version": "2.0.0",
+  "version": "2.0.1",
   "description": "The Usher Authorization Server",
   "engines": {
     "node": ">=18"
@@ -32,6 +32,7 @@
     "js-yaml": "4.1.0",
     "jwks-rsa": "3.1.0",
     "moment": "2.30.1",
+    "node-cache": "5.1.2",
     "oas-tools": "2.2.2",
     "pem-jwk": "2.0.0",
     "serverless-http": "3.1.0",

server/src/api_endpoints/endpoint_jwksjson.js

@@ -1,16 +1,28 @@
 const keystore = require('database/layer/db-keys')
 const { pem2jwk } = require('pem-jwk')
 const createError = require('http-errors')
+const NodeCache = require('node-cache')
 
+const myCache = new NodeCache({ stdTTL: 60, checkperiod: 30 })
 const getJwks = async (req, res) => {
   try {
-    const keyPairs = await keystore.selectAllKeys()
-    const publicKeys = keyPairs?.map(keyPair => {
-      const item = pem2jwk(keyPair.public_key)
-      item.kid = keyPair.kid
-      return item
-    })
-    res.status(200).send({ keys: publicKeys })
+    const cacheKeyName = 'usher-jwks'
+    let response = myCache.get(cacheKeyName)
+
+    if (response) {
+      res.set('x-cache', 'Hit from Usher')
+    } else {
+      const keyPairs = await keystore.selectAllKeys()
+      const publicKeys = keyPairs?.map(keyPair => {
+        const item = pem2jwk(keyPair.public_key)
+        item.kid = keyPair.kid
+        return item
+      })
+      response = { keys: publicKeys }
+      myCache.set(cacheKeyName, response)
+    }
+
+    res.status(200).send(response)
   } catch ({ httpStatusCode = 500, message }) {
     return next(createError(httpStatusCode, { message }))
   }

server/test/endpoint_jwks.test.js

@@ -6,12 +6,19 @@ const { getServerUrl } = require('./lib/urls')
 
 describe('Get JWKS', () => {
   const url = `${getServerUrl()}/.well-known/jwks.json`
+  const fetchJWKS = () => fetch(url, { method: 'GET', headers: { 'Content-Type': 'application/json' } });
 
-  it('should return a JWKS containing a list of keys', async function () {
-    const response = await fetch(url, { method: 'GET', headers: { 'Content-Type': 'application/json' } })
-    assert.strictEqual(response.status, 200)
+  it('should return a JWKS containing a list of keys', async () => {
+    const response = await fetchJWKS()
+    assert.equal(response.status, 200)
     const jwks = await response.json()
     assert('keys' in jwks, 'There should be a keys element in the object.')
     assert(jwks.keys.length > 0, 'There should be at least one key in the keys array')
   })
+
+  it('should return a JWKS from internal cache', async () => {
+    const response = await fetchJWKS()
+    assert.equal(response.status, 200)
+    assert.equal(response.headers.get('x-cache'), 'Hit from Usher')
+  })
 })