cache the search API (#25068)

* cache the search API

* extend tests

Author: peterbe

middleware/search.js

@@ -2,17 +2,15 @@ import express from 'express'
 import libLanguages from '../lib/languages.js'
 import searchVersions from '../lib/search/versions.js'
 import loadLunrResults from '../lib/search/lunr-search.js'
+import { cacheControlFactory } from './cache-control.js'
+
 const languages = new Set(Object.keys(libLanguages))
 const versions = new Set(Object.values(searchVersions))
-
 const router = express.Router()
+const cacheControl = cacheControlFactory(60 * 60 * 24)
+const noCacheControl = cacheControlFactory(0)
 
-router.get('/', async function postSearch(req, res, next) {
-  res.set({
-    'surrogate-control': 'private, no-store',
-    'cache-control': 'private, no-store',
-  })
-
+router.get('/', async function getSearch(req, res, next) {
   const { query, version, language, filters, limit: limit_ } = req.query
   const limit = Math.min(parseInt(limit_, 10) || 10, 100)
   if (!versions.has(version) || !languages.has(language)) {
@@ -31,12 +29,19 @@ router.get('/', async function postSearch(req, res, next) {
     })
     // Only reply if the headers have not been sent and the request was not aborted...
     if (!res.headersSent && !req.aborted) {
+      cacheControl(res)
+
+      // Undo the cookie setting that CSRF sets.
+      // Otherwise it can't be cached in the CDN.
+      res.removeHeader('set-cookie')
+
       return res.status(200).json(results)
     }
   } catch (err) {
     console.error(err)
     // Only reply if the headers have not been sent and the request was not aborted...
     if (!res.headersSent && !req.aborted) {
+      noCacheControl(res)
       return res.status(400).json({ error: err.toString() })
     }
   }

tests/content/search.js

@@ -60,6 +60,11 @@ describe('search middleware', () => {
     expect(res.statusCode).toBe(200)
     const results = JSON.parse(res.text)
     expect(Array.isArray(results)).toBeTruthy()
+
+    // Check that it can be cached at the CDN
+    expect(res.headers['set-cookie']).toBeUndefined()
+    expect(res.headers['cache-control']).toContain('public')
+    expect(res.headers['cache-control']).toMatch(/max-age=\d+/)
   })
 
   test('limit search', async () => {