Add support for subscribing to channels via PubSubHubbub

config/migrate-scripts/migrate-db-17cf077.sh

@@ -0,0 +1,4 @@
+#!/bin/sh
+
+psql invidious -c "ALTER TABLE channels ADD COLUMN subscribed bool;"
+psql invidious -c "UPDATE channels SET subscribed = false;"

src/invidious.cr

@@ -28,7 +28,7 @@ require "./invidious/helpers/*"
 require "./invidious/*"
 
 CONFIG   = Config.from_yaml(File.read("config/config.yml"))
-HMAC_KEY = CONFIG.hmac_key || Random::Secure.random_bytes(32)
+HMAC_KEY = CONFIG.hmac_key || Random::Secure.hex(32)
 
 config = CONFIG
 logger = Invidious::LogHandler.new
@@ -88,6 +88,7 @@ PG_DB           = DB.open PG_URL
 YT_URL          = URI.parse("https://www.youtube.com")
 REDDIT_URL      = URI.parse("https://www.reddit.com")
 LOGIN_URL       = URI.parse("https://accounts.google.com")
+PUBSUB_URL      = URI.parse("https://pubsubhubbub.appspot.com")
 TEXTCAPTCHA_URL = URI.parse("http://textcaptcha.com/omarroth@hotmail.com.json")
 CURRENT_COMMIT  = `git rev-list HEAD --max-count=1 --abbrev-commit`.strip
 CURRENT_VERSION = `git describe --tags $(git rev-list --tags --max-count=1)`.strip
@@ -115,6 +116,8 @@ refresh_channels(PG_DB, logger, config.channel_threads, config.full_refresh)
 
 refresh_feeds(PG_DB, logger, config.feed_threads)
 
+subscribe_to_feeds(PG_DB, logger, HMAC_KEY, config)
+
 config.video_threads.times do |i|
   spawn do
     refresh_videos(PG_DB, logger)
@@ -2314,6 +2317,58 @@ get "/feed/playlist/:plid" do |env|
   document
 end
 
+# Add support for subscribing to channels via PubSubHubbub
+
+get "/feed/webhook" do |env|
+  mode = env.params.query["hub.mode"]
+  topic = env.params.query["hub.topic"]
+  challenge = env.params.query["hub.challenge"]
+  lease_seconds = env.params.query["hub.lease_seconds"]
+  verify_token = env.params.query["hub.verify_token"]
+
+  time, signature = verify_token.split(":")
+
+  if Time.now.to_unix - time.to_i > 600
+    halt env, status_code: 400
+  end
+
+  if OpenSSL::HMAC.hexdigest(:sha1, HMAC_KEY, time) != signature
+    halt env, status_code: 400
+  end
+
+  ucid = HTTP::Params.parse(URI.parse(topic).query.not_nil!)["channel_id"]
+  PG_DB.exec("UPDATE channels SET subscribed = true WHERE ucid = $1", ucid)
+
+  halt env, status_code: 200, response: challenge
+end
+
+post "/feed/webhook" do |env|
+  body = env.request.body.not_nil!.gets_to_end
+  signature = env.request.headers["X-Hub-Signature"].lchop("sha1=")
+
+  if signature != OpenSSL::HMAC.hexdigest(:sha1, HMAC_KEY, body)
+    halt env, status_code: 200
+  end
+
+  rss = XML.parse_html(body)
+  rss.xpath_nodes("//feed/entry").each do |entry|
+    id = entry.xpath_node("videoid").not_nil!.content
+
+    video = get_video(id, PG_DB, proxies)
+    video = ChannelVideo.new(id, video.title, video.published, Time.now, video.ucid, video.author, video.length_seconds)
+
+    PG_DB.exec("UPDATE users SET notifications = notifications || $1 \
+      WHERE updated < $2 AND $3 = ANY(subscriptions) AND $1 <> ALL(notifications)", video.id, video.published, video.ucid)
+
+    video_array = video.to_a
+    args = arg_array(video_array)
+
+    PG_DB.exec("INSERT INTO channel_videos VALUES (#{args}) \
+    ON CONFLICT (id) DO UPDATE SET title = $2, published = $3, \
+    updated = $4, ucid = $5, author = $6, length_seconds = $7", video_array)
+  end
+end
+
 # Channels
 
 # YouTube appears to let users set a "brand" URL that

src/invidious/channels.cr

@@ -4,6 +4,7 @@ class InvidiousChannel
     author:     String,
     updated:    Time,
     deleted:    Bool,
+    subscribed: {type: Bool, default: false},
   })
 end
 
@@ -15,10 +16,7 @@ class ChannelVideo
     updated:        Time,
     ucid:           String,
     author:         String,
-    length_seconds: {
-      type:    Int32,
-      default: 0,
-    },
+    length_seconds: {type: Int32, default: 0},
   })
 end
 
@@ -188,11 +186,29 @@ def fetch_channel(ucid, db, pull_all_videos = true, locale = nil)
     db.exec("DELETE FROM channel_videos * WHERE NOT id = ANY ('{#{ids.map { |id| %("#{id}") }.join(",")}}') AND ucid = $1", ucid)
   end
 
-  channel = InvidiousChannel.new(ucid, author, Time.now, false)
+  channel = InvidiousChannel.new(ucid, author, Time.now, false, false)
 
   return channel
 end
 
+def subscribe_pubsub(ucid, key, config)
+  client = make_client(PUBSUB_URL)
+  time = Time.now.to_unix.to_s
+
+  host_url = make_host_url(Kemal.config.ssl || config.https_only, config.domain)
+
+  body = {
+    "hub.callback"     => "#{host_url}/feed/webhook",
+    "hub.topic"        => "https://www.youtube.com/feeds/videos.xml?channel_id=#{ucid}",
+    "hub.verify"       => "async",
+    "hub.mode"         => "subscribe",
+    "hub.verify_token" => "#{time}:#{OpenSSL::HMAC.hexdigest(:sha1, key, time)}",
+    "hub.secret"       => key.to_s,
+  }
+
+  return client.post("/subscribe", form: body)
+end
+
 def fetch_channel_playlists(ucid, author, auto_generated, continuation, sort_by)
   client = make_client(YT_URL)
 

src/invidious/helpers/helpers.cr

@@ -13,8 +13,9 @@ user: String,
     ),
     full_refresh:         Bool,                         # Used for crawling channels: threads should check all videos uploaded by a channel
     https_only:           Bool?,                        # Used to tell Invidious it is behind a proxy, so links to resources should be https://
-    hmac_key:             String?, # HMAC signing key for CSRF tokens
+    hmac_key:             String?,                      # HMAC signing key for CSRF tokens and verifying pubsub subscriptions
     domain:               String?,                      # Domain to be used for links to resources on the site where an absolute URL is required
+    use_pubsub_feeds:     {type: Bool, default: false}, # Subscribe to channels using PubSubHubbub (requires domain, hmac_key)
     default_home:         {type: String, default: "Top"},
     feed_menu:            {type: Array(String), default: ["Popular", "Top", "Trending"]},
     top_enabled:          {type: Bool, default: true},

src/invidious/jobs.cr

@@ -153,6 +153,26 @@ def refresh_feeds(db, logger, max_threads = 1)
   max_channel.send(max_threads)
 end
 
+def subscribe_to_feeds(db, logger, key, config)
+  if config.use_pubsub_feeds
+    spawn do
+      loop do
+        db.query_all("SELECT ucid FROM channels WHERE subscribed = false") do |rs|
+          ucid = rs.read(String)
+          response = subscribe_pubsub(ucid, key, config)
+
+          if response.status_code >= 400
+            logger.write("#{ucid} : #{response.body}\n")
+          end
+        end
+
+        sleep 1.minute
+        Fiber.yield
+      end
+    end
+  end
+end
+
 def pull_top_videos(config, db)
   loop do
     begin