feature: initial syndication feeds support

Provides rss 2.0, atom 1.0 and json 1.0 feeds for videos (instance and account-wide) on listings and video-watch views.

* still lacks redis caching
* still lacks lastBuildDate support
* still lacks channel-wide support
* still lacks semantic annotation (for licenses, NSFW warnings, etc.)
* still lacks love ( ˘ ³˘)

* RSS: has MRSS support for torrent lists!
* RSS: includes the first torrent in an enclosure
* JSON: lists all torrents in the 'attachments' object
* ATOM: lacking torrent listing support

Advances #23
Partial implementation for the accountId generation in the client, which will need a hotfix to add a way to get the proper account id.

server/controllers/feeds.ts

@@ -0,0 +1,136 @@
+import * as express from 'express'
+import { CONFIG } from '../initializers'
+import { asyncMiddleware, feedsValidator } from '../middlewares'
+import { VideoModel } from '../models/video/video'
+import * as Feed from 'pfeed'
+import { ResultList } from '../../shared/models'
+import { AccountModel } from '../models/account/account'
+
+const feedsRouter = express.Router()
+
+feedsRouter.get('/feeds/videos.:format',
+  asyncMiddleware(feedsValidator),
+  asyncMiddleware(generateFeed)
+)
+
+// ---------------------------------------------------------------------------
+
+export {
+  feedsRouter
+}
+
+// ---------------------------------------------------------------------------
+
+async function generateFeed (req: express.Request, res: express.Response, next: express.NextFunction) {
+  let feed = initFeed()
+  let feedStart = 0
+  let feedCount = 10
+  let feedSort = '-createdAt'
+
+  let resultList: ResultList<VideoModel>
+  const account: AccountModel = res.locals.account
+
+  if (account) {
+    resultList = await VideoModel.listUserVideosForApi(
+      account.id,
+      feedStart,
+      feedCount,
+      feedSort,
+      true
+    )
+  } else {
+    resultList = await VideoModel.listForApi(
+      feedStart,
+      feedCount,
+      feedSort,
+      req.query.filter,
+      true
+    )
+  }
+
+  // Adding video items to the feed, one at a time
+  resultList.data.forEach(video => {
+    const formattedVideoFiles = video.getFormattedVideoFilesJSON()
+    const torrents = formattedVideoFiles.map(videoFile => ({
+      title: video.name,
+      url: videoFile.torrentUrl,
+      size_in_bytes: videoFile.size
+    }))
+
+    feed.addItem({
+      title: video.name,
+      id: video.url,
+      link: video.url,
+      description: video.getTruncatedDescription(),
+      content: video.description,
+      author: [
+        {
+          name: video.VideoChannel.Account.getDisplayName(),
+          link: video.VideoChannel.Account.Actor.url
+        }
+      ],
+      date: video.publishedAt,
+      language: video.language,
+      nsfw: video.nsfw,
+      torrent: torrents
+    })
+  })
+
+  // Now the feed generation is done, let's send it!
+  return sendFeed(feed, req, res)
+}
+
+function initFeed () {
+  const webserverUrl = CONFIG.WEBSERVER.URL
+
+  return new Feed({
+    title: CONFIG.INSTANCE.NAME,
+    description: CONFIG.INSTANCE.SHORT_DESCRIPTION,
+    // updated: TODO: somehowGetLatestUpdate, // optional, default = today
+    id: webserverUrl,
+    link: webserverUrl,
+    image: webserverUrl + '/client/assets/images/icons/icon-96x96.png',
+    favicon: webserverUrl + '/client/assets/images/favicon.png',
+    copyright: `All rights reserved, unless otherwise specified in the terms specified at ${webserverUrl}/about` +
+    ` and potential licenses granted by each content's rightholder.`,
+    generator: `Toraifōsu`, // ^.~
+    feedLinks: {
+      json: `${webserverUrl}/feeds/videos.json`,
+      atom: `${webserverUrl}/feeds/videos.atom`,
+      rss: `${webserverUrl}/feeds/videos.xml`
+    },
+    author: {
+      name: 'instance admin of ' + CONFIG.INSTANCE.NAME,
+      email: CONFIG.ADMIN.EMAIL,
+      link: `${webserverUrl}/about`
+    }
+  })
+}
+
+function sendFeed (feed, req: express.Request, res: express.Response) {
+  const format = req.params.format
+
+  if (format === 'atom' || format === 'atom1') {
+    res.set('Content-Type', 'application/atom+xml')
+    return res.send(feed.atom1()).end()
+  }
+
+  if (format === 'json' || format === 'json1') {
+    res.set('Content-Type', 'application/json')
+    return res.send(feed.json1()).end()
+  }
+
+  if (format === 'rss' || format === 'rss2') {
+    res.set('Content-Type', 'application/rss+xml')
+    return res.send(feed.rss2()).end()
+  }
+
+  // We're in the ambiguous '.xml' case and we look at the format query parameter
+  if (req.query.format === 'atom' || req.query.format === 'atom1') {
+    res.set('Content-Type', 'application/atom+xml')
+    return res.send(feed.atom1()).end()
+  }
+
+  res.set('Content-Type', 'application/rss+xml')
+  return res.send(feed.rss2()).end()
+}