Support for Category-Page Metadata definition.

## Issue
Part of 4786: Add support for web metadata on category pages

## Note
Remaining task: `category-metadata.js` needs to be filled first.

ui/constants/pages.js

@@ -7,6 +7,18 @@ exports.AUTH_WALLET_PASSWORD = 'walletpassword';
 exports.BACKUP = 'backup';
 exports.CHANNEL = 'channel';
 exports.DISCOVER = 'discover';
+exports.BIG_HITS = 'big_hits';
+exports.COMMUNITY = 'community';
+exports.ENLIGHTENMENT = 'enlightenment';
+exports.FINANCE = 'finance';
+exports.GAMING = 'gaming';
+exports.GENERAL = 'general';
+exports.LAB = 'lab';
+exports.NEWS = 'news';
+exports.RABBIT_HOLE = 'rabbithole';
+exports.SCIENCE = 'science';
+exports.TECHNOLOGY = 'technology';
+exports.WILD_WEST = 'wildwest';
 exports.HOME = 'home';
 exports.HELP = 'help';
 exports.LIBRARY = 'library';

web/src/category-metadata.js

@@ -0,0 +1,64 @@
+const PAGES = require('../../ui/constants/pages');
+
+module.exports.CATEGORY_METADATA = {
+  [PAGES.BIG_HITS]: {
+    title: '',
+    description: '',
+    image: '',
+  },
+  [PAGES.COMMUNITY]: {
+    title: '',
+    description: '',
+    image: '',
+  },
+  [PAGES.ENLIGHTENMENT]: {
+    title: '',
+    description: '',
+    image: '',
+  },
+  [PAGES.FINANCE]: {
+    title: '',
+    description: '',
+    image: '',
+  },
+  [PAGES.GAMING]: {
+    title: '',
+    description: '',
+    image: '',
+  },
+  [PAGES.GENERAL]: {
+    title: '',
+    description: '',
+    image: '',
+  },
+  [PAGES.LAB]: {
+    title: '',
+    description: '',
+    image: '',
+  },
+  [PAGES.NEWS]: {
+    title: '',
+    description: '',
+    image: '',
+  },
+  [PAGES.RABBIT_HOLE]: {
+    title: '',
+    description: '',
+    image: '',
+  },
+  [PAGES.SCIENCE]: {
+    title: '',
+    description: '',
+    image: '',
+  },
+  [PAGES.TECHNOLOGY]: {
+    title: '',
+    description: '',
+    image: '',
+  },
+  [PAGES.WILD_WEST]: {
+    title: '',
+    description: '',
+    image: '',
+  },
+};

web/src/html.js

@@ -10,6 +10,7 @@ const {
 } = require('../../config.js');
 const { generateEmbedUrl, generateStreamUrl } = require('../../ui/util/web');
 const PAGES = require('../../ui/constants/pages');
+const { CATEGORY_METADATA } = require('./category-metadata');
 const { getClaim } = require('./chainquery');
 const { parseURI } = require('lbry-redux');
 const fs = require('fs');
@@ -43,6 +44,11 @@ function escapeHtmlProperty(property) {
     : '';
 }
 
+function getCategoryMeta(path) {
+  const page = Object.keys(CATEGORY_METADATA).find((x) => path.endsWith(x) || path.endsWith(`${x}/`));
+  return CATEGORY_METADATA[page];
+}
+
 //
 // Normal metadata with option to override certain values
 //
@@ -57,16 +63,17 @@ function buildOgMetadata(overrideOptions = {}) {
     `<meta property="og:description" content="${cleanDescription}" />\n` +
     `<meta property="og:image" content="${OG_IMAGE_URL || `${URL}/public/v2-og.png`}" />\n` +
     '<meta name="twitter:card" content="summary_large_image"/>\n' +
-    `<meta name="twitter:title" content="${(title && title + OG_TITLE_SUFFIX) ||
+    `<meta name="twitter:title" content="${
-      OG_HOMEPAGE_TITLE ||
+      (title && title + OG_TITLE_SUFFIX) || OG_HOMEPAGE_TITLE || SITE_TITLE
-      SITE_TITLE}" />\n` +
+    }" />\n` +
     `<meta name="twitter:description" content="${cleanDescription}" />\n` +
     `<meta name="twitter:image" content="${OG_IMAGE_URL || `${URL}/public/v2-og.png`}"/>\n` +
     `<meta name="twitter:url" content="${URL}" />\n` +
     '<meta property="fb:app_id" content="1673146449633983" />\n' +
     `<link rel="canonical" content="${SITE_CANONICAL_URL || URL}"/>` +
-    `<link rel="search" type="application/opensearchdescription+xml" title="${SITE_NAME ||
+    `<link rel="search" type="application/opensearchdescription+xml" title="${
-      SITE_TITLE}" href="${URL}/opensearch.xml">`;
+      SITE_NAME || SITE_TITLE
+    }" href="${URL}/opensearch.xml">`;
   return head;
 }
 
@@ -229,6 +236,16 @@ async function getHtml(ctx) {
     return insertToHead(html);
   }
 
+  const categoryMeta = getCategoryMeta(requestPath);
+  if (categoryMeta) {
+    const categoryPageMetadata = buildOgMetadata({
+      title: categoryMeta.title,
+      description: categoryMeta.description,
+      image: categoryMeta.image,
+    });
+    return insertToHead(html, categoryPageMetadata);
+  }
+
   if (!requestPath.includes('$')) {
     const claimUri = requestPath.slice(1).replace(/:/g, '#');
     const claim = await getClaimFromChainqueryOrRedirect(ctx, claimUri);