feat: enable ETag header

fix #80
nuxt-community · Apr 5, 2020 · ccf3e10 · ccf3e10
1 parent 2ca7fe6
commit ccf3e10
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Showing 6 changed files with 658 additions and 531 deletions.
diff --git a/README.md b/README.md
@@ -193,6 +193,16 @@ Please note that after each invalidation, `routes` will be evaluated again. (See
 
 This option is enable only for the nuxt "universal" mode.
 
+### `etag` (optional) - object
+
+- Default: [`render.etag`](https://nuxtjs.org/api/configuration-render#etag) value from your `nuxt.config.js`
+
+Enable the etag cache header on sitemap (See [etag](https://nuxtjs.org/api/configuration-render#etag) docs for possible options).
+
+To disable etag for sitemap set `etag: false`
+
+This option is enable only for the nuxt "universal" mode.
+
 ### `exclude` (optional) - string array
 
 - Default: `[]`

diff --git a/lib/middleware.js b/lib/middleware.js
@@ -1,5 +1,8 @@
 const { gzipSync } = require('zlib')
 
+const generateETag = require('etag')
+const fresh = require('fresh')
+
 const { createSitemap, createSitemapIndex } = require('./builder')
 const { createRoutesCache } = require('./cache')
 const logger = require('./logger')
@@ -66,6 +69,10 @@ function registerSitemap(options, globalCache, nuxtInstance) {
           // Init sitemap
           const routes = await cache.routes.get('routes')
           const gzip = await createSitemap(options, routes, base, req).toGzip()
+          // Check cache headers
+          if (validHttpCache(gzip, options.etag, req, res)) {
+            return
+          }
           // Send http response
           res.setHeader('Content-Type', 'application/gzip')
           res.end(gzip)
@@ -90,6 +97,10 @@ function registerSitemap(options, globalCache, nuxtInstance) {
         // Init sitemap
         const routes = await cache.routes.get('routes')
         const xml = await createSitemap(options, routes, base, req).toXML()
+        // Check cache headers
+        if (validHttpCache(xml, options.etag, req, res)) {
+          return
+        }
         // Send http response
         res.setHeader('Content-Type', 'application/xml')
         res.end(xml)
@@ -142,4 +153,30 @@ function registerSitemapIndex(options, globalCache, nuxtInstance, depth = 0) {
   options.sitemaps.forEach((sitemapOptions) => registerSitemaps(sitemapOptions, globalCache, nuxtInstance, depth + 1))
 }
 
+/**
+ * Validate the freshness of HTTP cache using headers
+ *
+ * @param {Object} entity
+ * @param {Object} options
+ * @param {Request} req
+ * @param {Response} res
+ * @returns {boolean}
+ */
+function validHttpCache(entity, options, req, res) {
+  if (!options) {
+    return false
+  }
+  const { hash } = options
+  const etag = hash ? hash(entity, options) : generateETag(entity, options)
+  if (fresh(req.headers, { etag })) {
+    // Resource not modified
+    res.statusCode = 304
+    res.end()
+    return true
+  }
+  // Add ETag header
+  res.setHeader('ETag', etag)
+  return false
+}
+
 module.exports = { registerSitemaps, registerSitemap, registerSitemapIndex }
diff --git a/lib/options.js b/lib/options.js
@@ -19,6 +19,7 @@ function setDefaultSitemapOptions(options, nuxtInstance) {
     exclude: [],
     routes: nuxtInstance.options.generate.routes || [],
     cacheTime: 1000 * 60 * 15,
+    etag: nuxtInstance.options.render.etag,
     filter: undefined,
     gzip: false,
     xmlNs: undefined,

diff --git a/package.json b/package.json
@@ -50,6 +50,8 @@
   "dependencies": {
     "async-cache": "^1.1.0",
     "consola": "^2.11.3",
+    "etag": "^1.8.1",
+    "fresh": "^0.5.2",
     "fs-extra": "^8.1.0",
     "is-https": "^1.0.0",
     "lodash.unionby": "^4.8.0",

diff --git a/test/module.test.js b/test/module.test.js
@@ -10,7 +10,7 @@ config.dev = false
 config.sitemap = {}
 
 const url = (path) => `http://localhost:3000${path}`
-const get = (path) => request(url(path))
+const get = (path, options = null) => request(url(path), options)
 const getGzip = (path) => request({ url: url(path), encoding: null })
 
 const startServer = async (config) => {
@@ -172,6 +172,69 @@ describe('sitemap - advanced configuration', () => {
   })
 
   describe('custom options', () => {
+    test('etag enabled', async () => {
+      nuxt = await startServer({
+        ...config,
+        sitemap: {
+          gzip: true,
+        },
+      })
+
+      const requestOptions = {
+        simple: false,
+        resolveWithFullResponse: true,
+      }
+
+      // 1st call
+      let response = await get('/sitemap.xml', requestOptions)
+      expect(response.statusCode).toEqual(200)
+      expect(response.headers.etag).not.toBeUndefined()
+      // 2nd call
+      response = await get('/sitemap.xml', {
+        headers: {
+          'If-None-Match': response.headers.etag,
+        },
+        ...requestOptions,
+      })
+      expect(response.statusCode).toEqual(304)
+
+      // 1st call
+      response = await get('/sitemap.xml.gz', requestOptions)
+      expect(response.statusCode).toEqual(200)
+      expect(response.headers.etag).not.toBeUndefined()
+      // 2nd call
+      response = await get('/sitemap.xml.gz', {
+        headers: {
+          'If-None-Match': response.headers.etag,
+        },
+        ...requestOptions,
+      })
+      expect(response.statusCode).toEqual(304)
+    })
+
+    test('etag disabled', async () => {
+      nuxt = await startServer({
+        ...config,
+        sitemap: {
+          etag: false,
+          gzip: true,
+        },
+      })
+
+      const requestOptions = {
+        simple: false,
+        resolveWithFullResponse: true,
+      }
+
+      let response = await get('/sitemap.xml', requestOptions)
+      expect(response.statusCode).toEqual(200)
+      expect(response.headers.etag).toBeUndefined()
+
+      response = await get('/sitemap.xml.gz', requestOptions)
+      expect(response.statusCode).toEqual(200)
+      expect(response.headers.etag).toBeUndefined()
+    })
+
     test('gzip enabled', async () => {
       nuxt = await startServer({
         ...config,