Stop generating sitemap.xml.gz (#6561) (#6562)

Co-authored-by: David Glick <[email protected]>

packages/volto/news/6561.bugfix

@@ -0,0 +1 @@
+Serve `sitemap.xml.gz` as an alias for `sitemap-index.xml`. @reebalazs

packages/volto/src/express-middleware/sitemap.js

@@ -47,11 +47,24 @@ export const sitemapIndex = function (req, res, next) {
   });
 };
 
+export const sitemapIndexCompatibility = function (req, res, next) {
+  generateSitemapIndex(req, true).then((sitemapIndex) => {
+    res.set('Content-Type', 'application/x-gzip');
+    res.set('Content-Disposition', 'attachment; filename="sitemap.xml.gz"');
+    res.send(sitemapIndex);
+  });
+};
+
 export default function sitemapMiddleware() {
   const middleware = express.Router();
 
-  middleware.all('**/sitemap.xml.gz', sitemap);
+  // For backwards compatibility, and allow a graceful transition for
+  // sites that are already set up on the Google Search Console, we continue delivering
+  // the new batched sitemap under the old sitemap.xml.gz name.
+  middleware.all('**/sitemap.xml.gz', sitemapIndexCompatibility);
   middleware.all('**/sitemap:batch.xml.gz', sitemap);
+  // For new setups, `sitemap-index.xml` should be added to the
+  // Google Search Console.
   middleware.all('**/sitemap-index.xml', sitemapIndex);
   middleware.id = 'sitemap.xml.gz';
   return middleware;

packages/volto/src/helpers/Sitemap/Sitemap.js

@@ -61,7 +61,7 @@ export const generateSitemap = (_req, start = 0, size = undefined) =>
  * @param {Object} _req Request object
  * @return {string} Generated sitemap index
  */
-export const generateSitemapIndex = (_req) =>
+export const generateSitemapIndex = (_req, gzip = false) =>
   new Promise((resolve) => {
     const { settings } = config;
     const APISUFIX = settings.legacyTraverse ? '' : '/++api++';
@@ -88,7 +88,14 @@ export const generateSitemapIndex = (_req) =>
         const result = `<?xml version="1.0" encoding="UTF-8"?>
 <sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
 ${items.join('\n')}\n</sitemapindex>`;
-        resolve(result);
+
+        if (gzip) {
+          zlib.gzip(Buffer.from(result, 'utf8'), (_err, buffer) => {
+            resolve(buffer);
+          });
+        } else {
+          resolve(result);
+        }
       }
     });
   });