Add description and icon to preview URLs for non-document resources #1242

When pasting a URL in some app or website that allows previewing the
link, for other resources than documents, you were offered an irrelevant
description. This patches aims to give a generic description of what is
Grist.

app/server/lib/sendAppPage.ts

@@ -159,8 +159,8 @@ export function makeSendAppPage({ server, staticDir, tag, testLogin, baseDomain
     const staticTag = options.tag || tag;
     // If boot tag is used, serve assets locally, otherwise respect
     // APP_STATIC_URL.
-    const staticOrigin = staticTag === 'boot' ? '' : (process.env.APP_STATIC_URL || '');
+    const staticOrigin = staticTag === 'boot' ? '' : (process.env.APP_STATIC_URL || config.homeUrl || '');
-    const staticBaseUrl = `${staticOrigin}/v/${staticTag}/`;
+    const staticBaseUrl = `${staticOrigin.replace(/\/*$/, '')}/v/${staticTag}/`;
     const customHeadHtmlSnippet = server.create.getExtraHeadHtml?.() ?? "";
     const warning = testLogin ? "<div class=\"dev_warning\">Authentication is not enforced</div>" : "";
     // Preload all languages that will be used or are requested by client.
@@ -174,8 +174,8 @@ export function makeSendAppPage({ server, staticDir, tag, testLogin, baseDomain
     ).join('\n');
     const content = fileContent
       .replace("<!-- INSERT WARNING -->", warning)
-      .replace("<!-- INSERT TITLE -->", getPageTitle(req, config))
+      .replace("<!-- INSERT TITLE -->", getPageTitle(config) ?? (translate(req, 'Loading') + "..."))
-      .replace("<!-- INSERT META -->", getPageMetadataHtmlSnippet(config))
+      .replace("<!-- INSERT META -->", getPageMetadataHtmlSnippet(req, config, staticBaseUrl))
       .replace("<!-- INSERT TITLE SUFFIX -->", getPageTitleSuffix(server.getGristConfig()))
       .replace("<!-- INSERT BASE -->", `<base href="${staticBaseUrl}">` + tagManagerSnippet)
       .replace("<!-- INSERT LOCALE -->", preloads)
@@ -271,11 +271,10 @@ function configuredPageTitleSuffix() {
  *
  * Note: The string returned is escaped and safe to insert into HTML.
  */
-function getPageTitle(req: express.Request, config: GristLoadConfig): string {
+function getPageTitle(config: GristLoadConfig): string|null {
   const maybeDoc = getDocFromConfig(config);
-  if (!maybeDoc) { return translate(req, 'Loading') + "..."; }
 
-  return handlebars.Utils.escapeExpression(maybeDoc.name);
+  return maybeDoc && handlebars.Utils.escapeExpression(maybeDoc.name);
 }
 
 /**
@@ -286,25 +285,26 @@ function getPageTitle(req: express.Request, config: GristLoadConfig): string {
  *
  * Note: The string returned is escaped and safe to insert into HTML.
  */
-function getPageMetadataHtmlSnippet(config: GristLoadConfig): string {
+function getPageMetadataHtmlSnippet(req: express.Request, config: GristLoadConfig, staticBaseUrl: string): string {
   const metadataElements: string[] = [];
   const maybeDoc = getDocFromConfig(config);
 
-  const description = maybeDoc?.options?.description;
+  const description = maybeDoc?.options?.description ?? String(translate(req, 'gristMetaDescription'));
-  if (description) {
+  const escapedDescription = handlebars.Utils.escapeExpression(description);
-    const content = handlebars.Utils.escapeExpression(description);
+  metadataElements.push(`<meta name="description" content="${escapedDescription}">`);
-    metadataElements.push(`<meta name="description" content="${content}">`);
+  metadataElements.push(`<meta property="og:description" content="${escapedDescription}">`);
-    metadataElements.push(`<meta property="og:description" content="${content}">`);
+  metadataElements.push(`<meta name="twitter:description" content="${escapedDescription}">`);
-    metadataElements.push(`<meta name="twitter:description" content="${content}">`);
-  }
 
-  const icon = maybeDoc?.options?.icon;
+  const icon = maybeDoc?.options?.icon ?? new URL('img/icon-grist.png', staticBaseUrl).href;
-  if (icon) {
+  const escapedIcon = handlebars.Utils.escapeExpression(icon);
-    const content = handlebars.Utils.escapeExpression(icon);
+  metadataElements.push(`<meta name="thumbnail" content="${escapedIcon}">`);
-    metadataElements.push(`<meta name="thumbnail" content="${content}">`);
+  metadataElements.push(`<meta property="og:image" content="${escapedIcon}">`);
-    metadataElements.push(`<meta property="og:image" content="${content}">`);
+  metadataElements.push(`<meta name="twitter:image" content="${escapedIcon}">`);
-    metadataElements.push(`<meta name="twitter:image" content="${content}">`);
+
-  }
+  const title = (getPageTitle(config) ?? translate(req, 'Welcome')) + getPageTitleSuffix(config);
+  // NB: We don't generate the content of the <title> tag here.
+  metadataElements.push(`<meta property="og:title" content="${title}">`);
+  metadataElements.push(`<meta name="twitter:title" content="${title}">`);
 
   return metadataElements.join('\n');
 }

static/locales/en.server.json

@@ -1,6 +1,8 @@
 {
   "sendAppPage": {
-    "Loading": "Loading"
+    "Loading": "Loading",
+    "gristMetaDescription": "Grist is the evolution of spreadsheets.",
+    "Welcome": "Welcome"
   },
   "oidc": {
     "emailNotVerifiedError": "Please verify your email with the identity provider, and log in again."

test/nbrowser/HomeIntro.ts

@@ -29,6 +29,7 @@ describe('HomeIntro', function() {
     });
 
     it('should should intro screen for anon', () => testIntroScreen({anon: true, team: false}));
+    it('should should set meta tags for URL previews', testMetaTags);
     it('should not show Other Sites section', testOtherSitesSection);
     it('should allow create/import from intro screen', testCreateImport.bind(null, false));
     it('should link to examples page from the intro', testExamplesPage);
@@ -129,6 +130,22 @@ describe('HomeIntro', function() {
     }
   }
 
+  async function testMetaTags() {
+    const expectedTitle = 'Welcome - Grist';
+    assert.equal(await driver.find('meta[name="twitter:title"]').getAttribute('content'), expectedTitle);
+    assert.equal(await driver.find('meta[property="og:title"]').getAttribute('content'), expectedTitle);
+
+    const expectedDescription = 'Grist is the evolution of spreadsheets.';
+    assert.equal(await driver.find('meta[name="description"]').getAttribute('content'), expectedDescription);
+    assert.equal(await driver.find('meta[name="twitter:description"]').getAttribute('content'), expectedDescription);
+    assert.equal(await driver.find('meta[property="og:description"]').getAttribute('content'), expectedDescription);
+
+    const gristIconFileName = 'icon-grist.png';
+    assert.include(await driver.find('meta[name="thumbnail"]').getAttribute('content'), gristIconFileName);
+    assert.include(await driver.find('meta[name="twitter:image"]').getAttribute('content'), gristIconFileName);
+    assert.include(await driver.find('meta[property="og:image"]').getAttribute('content'), gristIconFileName);
+  }
+
   async function testCreateImport(isLoggedIn: boolean) {
     await checkIntroButtons(isLoggedIn);
 

test/nbrowser/NewDocument.ntest.js

@@ -18,7 +18,22 @@ describe('NewDocument.ntest', function() {
     this.timeout(10000);
     await gu.actions.createNewDoc('Untitled');
     assert.equal(await gu.actions.getDocTitle(), 'Untitled');
-    assert.equal(await driver.getTitle(), 'Untitled - Grist');
+
+    const expectedTitle = 'Untitled - Grist';
+    assert.equal(await driver.getTitle(), expectedTitle);
+    assert.equal(await driver.find('meta[name="twitter:title"]').getAttribute('content'), expectedTitle);
+    assert.equal(await driver.find('meta[property="og:title"]').getAttribute('content'), expectedTitle);
+
+    const expectedDescription = 'Grist is the evolution of spreadsheets.';
+    assert.equal(await driver.find('meta[name="description"]').getAttribute('content'), expectedDescription);
+    assert.equal(await driver.find('meta[name="twitter:description"]').getAttribute('content'), expectedDescription);
+    assert.equal(await driver.find('meta[property="og:description"]').getAttribute('content'), expectedDescription);
+
+    const gristIconFileName = 'icon-grist.png';
+    assert.include(await driver.find('meta[name="thumbnail"]').getAttribute('content'), gristIconFileName);
+    assert.include(await driver.find('meta[name="twitter:image"]').getAttribute('content'), gristIconFileName);
+    assert.include(await driver.find('meta[property="og:image"]').getAttribute('content'), gristIconFileName);
+
     assert.equal(await $('.active_section .test-viewsection-title').wait().text(), 'TABLE1');
     await gu.waitForServer();
   });