RSS: podcast support

## Issue
`https://github.com/lbryio/lbry-desktop/issues/6369#issuecomment-882081892`

## Changes
- Replace 'feed' with 'node-rss' for itunes spec support.
- Replace content type from 'rss+xml' to 'xml' so that the browser will display it nicely using the document tree without us having to re-format it ('node-rss' does not). Seems like all feeds that I found does it this way.
- There is no need to escape characters now that 'node-rss' does it. Nice.

package.json

@@ -54,12 +54,12 @@
     "electron-notarize": "^1.0.0",
     "electron-updater": "^4.2.4",
     "express": "^4.17.1",
-    "feed": "^4.2.2",
     "if-env": "^1.0.4",
     "react-datetime-picker": "^3.2.1",
     "react-plastic": "^1.1.1",
     "react-top-loading-bar": "^2.0.1",
     "remove-markdown": "^0.3.0",
+    "rss": "^1.2.2",
     "source-map-explorer": "^2.5.2",
     "tempy": "^0.6.0",
     "videojs-contrib-ads": "^6.9.0",

web/src/routes.js

@@ -19,9 +19,11 @@ function getStreamUrl(ctx) {
 }
 
 const rssMiddleware = async (ctx) => {
-  const xml = await getRss(ctx);
+  const rss = await getRss(ctx);
-  ctx.set('Content-Type', 'application/rss+xml');
+  if (rss.startsWith('<?xml')) {
-  ctx.body = xml;
+    ctx.set('Content-Type', 'application/xml');
+  }
+  ctx.body = rss;
 };
 
 router.get(`/$/api/content/v1/get`, async (ctx) => {

web/src/rss.js

@@ -1,7 +1,7 @@
 const { generateDownloadUrl } = require('../../ui/util/web');
-const { URL, SITE_NAME, LBRY_WEB_API, FAVICON } = require('../../config.js');
+const { URL, SITE_NAME, LBRY_WEB_API } = require('../../config.js');
 const { Lbry } = require('lbry-redux');
-const Feed = require('feed').Feed;
+const Rss = require('rss');
 
 const SDK_API_PATH = `${LBRY_WEB_API}/api/v1`;
 const proxyURL = `${SDK_API_PATH}/proxy`;
@@ -9,6 +9,10 @@ Lbry.setDaemonConnectionString(proxyURL);
 
 const NUM_ENTRIES = 500;
 
+// ****************************************************************************
+// Fetch claim info
+// ****************************************************************************
+
 async function doClaimSearch(options) {
   let results;
   try {
@@ -19,15 +23,21 @@ async function doClaimSearch(options) {
 
 async function getChannelClaim(name, claimId) {
   let claim;
+  let error;
+
   try {
     const url = `lbry://${name}#${claimId}`;
     const response = await Lbry.resolve({ urls: [url] });
-
     if (response && response[url] && !response[url].error) {
       claim = response && response[url];
     }
   } catch {}
-  return claim || 'The RSS URL is invalid or is not associated with any channel.';
+
+  if (!claim) {
+    error = 'The RSS URL is invalid or is not associated with any channel.';
+  }
+
+  return { claim, error };
 }
 
 async function getClaimsFromChannel(claimId, count) {
@@ -43,103 +53,218 @@ async function getClaimsFromChannel(claimId, count) {
   return await doClaimSearch(options);
 }
 
-async function getFeed(channelClaim, feedLink) {
+// ****************************************************************************
-  const replaceLineFeeds = (str) => str.replace(/(?:\r\n|\r|\n)/g, '<br />');
+// Helpers
+// ****************************************************************************
 
-  const fmtDescription = (description) => replaceLineFeeds(description);
+const generateEnclosureForClaimContent = (claim) => {
+  const value = claim.value;
+  if (!value || !value.stream_type) {
+    return undefined;
+  }
 
-  const sanitizeThumbsUrl = (url) => {
+  switch (value.stream_type) {
-    if (typeof url === 'string' && url.startsWith('https://')) {
+    case 'video':
-      return encodeURI(url).replace(/&/g, '%26');
+    case 'audio':
-    }
+    case 'image':
-    return '';
+    case 'document':
-  };
+    case 'software':
+      return {
+        url: generateDownloadUrl(claim.name, claim.claim_id),
+        type: (value.source && value.source.media_type) || undefined,
+        size: (value.source && value.source.size) || 0, // Per spec, 0 is a valid fallback.
+      };
 
-  const getEnclosure = (claim) => {
+    default:
-    const value = claim.value;
-    if (!value || !value.stream_type || !value.source || !value.source.media_type) {
       return undefined;
+  }
+};
+
+const getLanguageValue = (claim) => {
+  if (claim && claim.value && claim.value.languages && claim.value.languages.length > 0) {
+    return claim.value.languages[0];
+  }
+  return 'en';
+};
+
+const replaceLineFeeds = (str) => str.replace(/(?:\r\n|\r|\n)/g, '<br />');
+
+const isEmailRoughlyValid = (email) => /^\S+@\S+$/.test(email);
+
+/**
+ * 'itunes:owner' is required by castfeedvalidator (w3c allows omission), and
+ * both name and email must be defined. The email must also be a "valid" one.
+ *
+ * Use a fallback email when the creator did not specify one. The email will not
+ * be shown to the user; it is just used for administrative purposes.
+ *
+ * @param claim
+ * @returns any
+ */
+const generateItunesOwnerElement = (claim) => {
+  let name = '---';
+  let email = 'no-reply@odysee.com';
+
+  if (claim && claim.value) {
+    name = claim.name;
+    if (isEmailRoughlyValid(claim.value.email)) {
+      email = claim.value.email;
     }
+  }
 
-    switch (value.stream_type) {
+  return {
-      case 'video':
+    'itunes:owner': [{ 'itunes:name': name }, { 'itunes:email': email }],
-      case 'audio':
+  };
-      case 'image':
+};
-      case 'document':
-      case 'software':
-        return {
-          url: encodeURI(generateDownloadUrl(claim.name, claim.claim_id)),
-          type: value.source.media_type,
-          length: value.source.size || 0, // Per spec, 0 is a valid fallback.
-        };
 
-      default:
+const generateItunesExplicitElement = (claim) => {
-        return undefined;
+  const tags = (claim && claim.value && claim.tags) || [];
+  return { 'itunes:explicit': tags.includes('mature') ? 'yes' : 'no' };
+};
+
+const getItunesCategory = (claim) => {
+  const itunesCategories = [
+    'Arts',
+    'Business',
+    'Comedy',
+    'Education',
+    'Fiction',
+    'Government',
+    'History',
+    'Health & Fitness',
+    'Kids & Family',
+    'Leisure',
+    'Music',
+    'News',
+    'Religion & Spirituality',
+    'Science',
+    'Society & Culture',
+    'Sports',
+    'Technology',
+    'True Crime',
+    'TV & Film',
+  ];
+
+  const tags = (claim && claim.value && claim.tags) || [];
+  for (let i = 0; i < tags.length; ++i) {
+    const tag = tags[i];
+    if (itunesCategories.includes(tag)) {
+      // "Note: Although you can specify more than one category and subcategory
+      // in your RSS feed, Apple Podcasts only recognizes the first category and
+      // subcategory."
+      // --> The only parse the first found tag.
+      return tag.replace('&', '&amp;');
     }
-  };
+  }
 
-  const value = channelClaim.value;
+  // itunes will not accept any other categories, and the element is required
-  const title = value ? value.title : channelClaim.name;
+  // to pass castfeedvalidator. So, fallback to 'Leisure' (closes to "General")
+  // if the creator did not specify a tag.
+  return 'Leisure';
+};
 
-  const options = {
+const generateItunesDurationElement = (claim) => {
-    favicon: FAVICON || URL + '/public/favicon.png',
+  let duration;
-    generator: SITE_NAME + ' RSS Feed',
+  if (claim && claim.value) {
-    title: title + ' on ' + SITE_NAME,
+    if (claim.value.video) {
-    description: fmtDescription(value && value.description ? value.description : ''),
+      duration = claim.value.video.duration;
-    link: encodeURI(`${URL}/${channelClaim.name}:${channelClaim.claim_id}`),
+    } else if (claim.value.audio) {
-    image: sanitizeThumbsUrl(value && value.thumbnail ? value.thumbnail.url : ''),
+      duration = claim.value.audio.duration;
-    feedLinks: {
+    }
-      rss: encodeURI(feedLink),
+  }
-    },
-    author: {
-      name: encodeURI(channelClaim.name),
-      link: encodeURI(URL + '/' + channelClaim.name + ':' + channelClaim.claim_id),
-    },
-  };
 
-  const feed = new Feed(options);
+  if (duration) {
-  const latestClaims = await getClaimsFromChannel(channelClaim.claim_id, NUM_ENTRIES);
+    return { 'itunes:duration': `${duration}` };
+  }
+};
 
-  latestClaims.forEach((c) => {
+const generateItunesImageElement = (claim) => {
-    const meta = c.meta;
+  const thumbnailUrl = (claim && claim.value && claim.value.thumbnail && claim.value.thumbnail.url) || '';
-    const value = c.value;
+  if (thumbnailUrl) {
+    return {
+      'itunes:image': { _attr: { href: thumbnailUrl } },
+    };
+  }
+};
 
-    const title = value && value.title ? value.title : c.name;
+const getFormattedDescription = (claim) => {
-    const thumbnailUrl = value && value.thumbnail ? value.thumbnail.url : '';
+  return replaceLineFeeds((claim && claim.value && claim.value.description) || '');
-    const thumbnailHtml = thumbnailUrl ? `<p><img src="${thumbnailUrl}" alt="thumbnail" title="${title}" /></p>` : '';
+};
 
-    feed.addItem({
+// ****************************************************************************
-      id: c.claim_id,
+// Generate
-      guid: encodeURI(URL + '/' + c.name + ':' + c.claim_id),
+// ****************************************************************************
-      title: value && value.title ? value.title : c.name,
+
-      description: thumbnailHtml + fmtDescription(value && value.description ? value.description : ''),
+function generateFeed(feedLink, channelClaim, claimsInChannel) {
-      link: encodeURI(URL + '/' + c.name + ':' + c.claim_id),
+  // --- Channel ---
-      date: new Date(meta ? meta.creation_timestamp * 1000 : null),
+  const feed = new Rss({
-      enclosure: getEnclosure(c),
+    title: ((channelClaim.value && channelClaim.value.title) || channelClaim.name) + ' on ' + SITE_NAME,
+    description: getFormattedDescription(channelClaim),
+    feed_url: feedLink,
+    site_url: URL,
+    image_url: (channelClaim.value && channelClaim.value.thumbnail && channelClaim.value.thumbnail.url) || undefined,
+    language: getLanguageValue(channelClaim),
+    custom_namespaces: { itunes: 'http://www.itunes.com/dtds/podcast-1.0.dtd' },
+    custom_elements: [
+      { 'itunes:author': channelClaim.name },
+      {
+        'itunes:category': [
+          {
+            _attr: {
+              text: getItunesCategory(channelClaim),
+            },
+          },
+        ],
+      },
+      generateItunesImageElement(channelClaim),
+      generateItunesOwnerElement(channelClaim),
+      generateItunesExplicitElement(channelClaim),
+    ],
+  });
+
+  // --- Content ---
+  claimsInChannel.forEach((c) => {
+    const title = (c.value && c.value.title) || c.name;
+    const thumbnailUrl = (c.value && c.value.thumbnail && c.value.thumbnail.url) || '';
+    const thumbnailHtml = thumbnailUrl
+      ? `<p><img src="${thumbnailUrl}" width="480" alt="thumbnail" title="${title}" /></p>`
+      : '';
+    const description = thumbnailHtml + getFormattedDescription(c);
+
+    feed.item({
+      title: title,
+      description: description,
+      url: `${URL}/${c.name}:${c.claim_id}`,
+      guid: undefined, // defaults to 'url'
+      author: undefined, // defaults feed author property
+      date: new Date(c.meta ? c.meta.creation_timestamp * 1000 : null),
+      enclosure: generateEnclosureForClaimContent(c),
+      custom_elements: [
+        { 'itunes:title': title },
+        { 'itunes:author': channelClaim.name },
+        generateItunesImageElement(c),
+        generateItunesDurationElement(c),
+        generateItunesExplicitElement(c),
+      ],
     });
   });
 
   return feed;
 }
 
-function postProcess(feed) {
-  // Handle 'Feed' creating an invalid MIME type when trying to guess
-  // from 'https://thumbnails.lbry.com/UCgQ8eREJzR1dO' style of URLs.
-  return feed.replace(/type="image\/\/.*"\/>/g, 'type="image/*"/>');
-}
-
 async function getRss(ctx) {
   if (!ctx.params.claimName || !ctx.params.claimId) {
     return 'Invalid URL';
   }
 
-  const channelClaim = await getChannelClaim(ctx.params.claimName, ctx.params.claimId);
+  const { claim: channelClaim, error } = await getChannelClaim(ctx.params.claimName, ctx.params.claimId);
-  if (typeof channelClaim === 'string' || !channelClaim) {
+  if (error) {
-    return channelClaim;
+    return error;
   }
 
-  const feed = await getFeed(channelClaim, `${URL}${ctx.request.url}`);
+  const latestClaimsInChannel = await getClaimsFromChannel(channelClaim.claim_id, NUM_ENTRIES);
-  return postProcess(feed.rss2());
+  const feed = generateFeed(`${URL}${ctx.request.url}`, channelClaim, latestClaimsInChannel);
+  return feed.xml();
 }
 
 module.exports = { getRss };

yarn.lock

@@ -7205,13 +7205,6 @@ fd-slicer@~1.1.0:
   dependencies:
     pend "~1.2.0"
 
-feed@^4.2.2:
-  version "4.2.2"
-  resolved "https://registry.yarnpkg.com/feed/-/feed-4.2.2.tgz#865783ef6ed12579e2c44bbef3c9113bc4956a7e"
-  integrity sha512-u5/sxGfiMfZNtJ3OvQpXcvotFpYkL0n9u9mM2vkui2nGo8b4wvDkJ8gAkYqbA8QpGyFCv3RK0Z+Iv+9veCS9bQ==
-  dependencies:
-    xml-js "^1.6.11"
-
 figgy-pudding@^3.5.1:
   version "3.5.2"
   resolved "https://registry.yarnpkg.com/figgy-pudding/-/figgy-pudding-3.5.2.tgz#b4eee8148abb01dcf1d1ac34367d59e12fa61d6e"
@@ -10908,6 +10901,18 @@ mime-db@1.48.0:
   resolved "https://registry.yarnpkg.com/mime-db/-/mime-db-1.48.0.tgz#e35b31045dd7eada3aaad537ed88a33afbef2d1d"
   integrity sha512-FM3QwxV+TnZYQ2aRqhlKBMHxk10lTbMt3bBkMAp54ddrNeVSfcQYOOKuGuy3Ddrm38I04If834fOUSq1yzslJQ==
 
+mime-db@~1.25.0:
+  version "1.25.0"
+  resolved "https://registry.yarnpkg.com/mime-db/-/mime-db-1.25.0.tgz#c18dbd7c73a5dbf6f44a024dc0d165a1e7b1c392"
+  integrity sha1-wY29fHOl2/b0SgJNwNFloeexw5I=
+
+mime-types@2.1.13:
+  version "2.1.13"
+  resolved "https://registry.yarnpkg.com/mime-types/-/mime-types-2.1.13.tgz#e07aaa9c6c6b9a7ca3012c69003ad25a39e92a88"
+  integrity sha1-4HqqnGxrmnyjASxpADrSWjnpKog=
+  dependencies:
+    mime-db "~1.25.0"
+
 mime-types@^2.1.12, mime-types@~2.1.19:
   version "2.1.31"
   resolved "https://registry.yarnpkg.com/mime-types/-/mime-types-2.1.31.tgz#a00d76b74317c61f9c2db2218b8e9f8e9c5c9e6b"
@@ -14307,6 +14312,14 @@ roarr@^2.15.3:
     semver-compare "^1.0.0"
     sprintf-js "^1.1.2"
 
+rss@^1.2.2:
+  version "1.2.2"
+  resolved "https://registry.yarnpkg.com/rss/-/rss-1.2.2.tgz#50a1698876138133a74f9a05d2bdc8db8d27a921"
+  integrity sha1-UKFpiHYTgTOnT5oF0r3I240nqSE=
+  dependencies:
+    mime-types "2.1.13"
+    xml "1.0.1"
+
 rtlcss@2.5.0:
   version "2.5.0"
   resolved "https://registry.yarnpkg.com/rtlcss/-/rtlcss-2.5.0.tgz#455549e49113f9e1cf83169a44de526c816de8a4"
@@ -17208,18 +17221,16 @@ xdg-basedir@^4.0.0:
   version "4.0.0"
   resolved "https://registry.yarnpkg.com/xdg-basedir/-/xdg-basedir-4.0.0.tgz#4bc8d9984403696225ef83a1573cbbcb4e79db13"
 
-xml-js@^1.6.11:
-  version "1.6.11"
-  resolved "https://registry.yarnpkg.com/xml-js/-/xml-js-1.6.11.tgz#927d2f6947f7f1c19a316dd8eea3614e8b18f8e9"
-  integrity sha512-7rVi2KMfwfWFl+GpPg6m80IVMWXLRjO+PxTq7V2CDhoGak0wzYzFgUY2m4XJ47OGdXd8eLE8EmwfAmdjw7lC1g==
-  dependencies:
-    sax "^1.2.4"
-
 xml-name-validator@^2.0.1:
   version "2.0.1"
   resolved "https://registry.yarnpkg.com/xml-name-validator/-/xml-name-validator-2.0.1.tgz#4d8b8f1eccd3419aa362061becef515e1e559635"
   integrity sha1-TYuPHszTQZqjYgYb7O9RXh5VljU=
 
+xml@1.0.1:
+  version "1.0.1"
+  resolved "https://registry.yarnpkg.com/xml/-/xml-1.0.1.tgz#78ba72020029c5bc87b8a81a3cfcd74b4a2fc1e5"
+  integrity sha1-eLpyAgApxbyHuKgaPPzXS0ovweU=
+
 xmlbuilder@^10.0.0:
   version "10.1.1"
   resolved "https://registry.yarnpkg.com/xmlbuilder/-/xmlbuilder-10.1.1.tgz#8cae6688cc9b38d850b7c8d3c0a4161dcaf475b0"