Use rel=canonical link to de-duplicate event permalinks

Fix #251
matrix-org · Jun 22, 2023 · fdfea11 · fdfea11
1 parent 3414fcf
commit fdfea11
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diff --git a/server/hydrogen-render/render-page-html.js b/server/hydrogen-render/render-page-html.js
@@ -71,6 +71,11 @@ function renderPageHtml({
     metaImageUrl = pageOptions.imageUrl;
   }
 
+  let maybeRelCanonical = '';
+  if (pageOptions.canonicalUrl) {
+    maybeRelCanonical = sanitizeHtml(`<link rel="canonical" href="${pageOptions.canonicalUrl}">`);
+  }
+
   const pageHtml = `
       <!doctype html>
       <html lang="en">
@@ -83,6 +88,7 @@ function renderPageHtml({
           ${sanitizeHtml(`<meta property="og:image" content="${metaImageUrl}">`)}
           <link rel="icon" href="${pageAssetUrls.faviconIco}" sizes="any">
           <link rel="icon" href="${pageAssetUrls.faviconSvg}" type="image/svg+xml">
+          ${maybeRelCanonical}
           ${styles
             .map(
               (styleUrl) =>

diff --git a/server/routes/room-routes.js b/server/routes/room-routes.js
@@ -917,6 +917,18 @@ router.get(
       blockedBySafeSearch: isNsfw,
       entryPoint: 'client/js/entry-client-hydrogen.js',
       locationHref: urlJoin(basePath, req.originalUrl),
+      canonicalUrl: matrixPublicArchiveURLCreator.archiveUrlForDate(
+        roomIdOrAlias,
+        new Date(toTimestamp),
+        {
+          preferredPrecision: precisionFromUrl,
+          // We purposely omit `scrollStartEventId` here because the canonical location
+          // for any given event ID is the page it resides on.
+          //
+          // We can avoid passing along the `viaServers` because we already joined the
+          // room above (see `ensureRoomJoined`).
+        }
+      ),
       shouldIndex,
       cspNonce: res.locals.cspNonce,
     };