Add endpoint to detect new recordings and update the interface

The endpoint receives events from BigBlueButton via webhooks or scripts
in the record and playback workflow.
For now it only treats the event for when a recording is ready.
When it happens, it uses action cable to update the interface dynamically
with the new recording.

app/assets/javascripts/channels/recording_update.js

@@ -26,23 +26,32 @@
 
         var recordings = Recordings.getInstance();
         var table = recordings.table.api();
-        var row = table.row("#"+data.record_id);
+        var row = table.row("#"+data.id);
 
         if (data.action === 'update') {
           var rowData = row.data();
 
           rowData.published = data.published;
           rowData.listed = data.listed;
-          table.row("#"+data.record_id).data(rowData);
+          table.row("#"+data.id).data(rowData);
           recordings.draw();
 
           var status = data.published ? (data.listed ? 'published' : 'unlisted') : 'unpublished';
           showAlert(I18n['recording_'+status], 4000);
+
         } else if (data.action === 'delete') {
           row.remove();
           recordings.draw();
-
           showAlert(I18n.recording_deleted, 4000);
+
+        } else if (data.action === 'create') {
+          if (row.length == 0) {
+            data.duration = data.length;
+            table.rows.add([data]);
+            recordings.draw();
+            showAlert(I18n.recording_created, 4000);
+          }
+
         }
       }
     });

app/assets/javascripts/recordings.coffee

@@ -166,13 +166,13 @@ class @Recordings
       listed = btn.data('visibility') == "published"
 
       btn.prop('disabled', true)
+
+      data = { published: published.toString() }
+      data["meta_" + GreenLight.META_LISTED] = listed.toString();
       $.ajax({
         method: 'PATCH',
         url: url+'/recordings/'+id,
-        data: {
-          published: published.toString(),
-          "meta_greenlight-listed": listed.toString()
-        }
+        data: data
       }).done((data) ->
 
       ).fail((data) ->

app/assets/javascripts/shared.js

@@ -34,6 +34,7 @@ var loopJoin = function() {
   });
 }
 
+var alertTimeout = null;
 var showAlert = function(html, timeout_delay) {
   if (!html) {
     return;
@@ -43,11 +44,12 @@ var showAlert = function(html, timeout_delay) {
   $('#alerts').html($('.alert-template').html());
 
   if (timeout_delay) {
-    setTimeout(function() {
+    clearTimeout(alertTimeout);
+    alertTimeout = setTimeout(function() {
       $('#alerts > .alert').alert('close');
     }, timeout_delay);
   }
-}
+};
 
 var displayRoomURL = function() {
   $('.meeting-url').val(Meeting.getInstance().getURL());

app/controllers/bbb_controller.rb

@@ -20,6 +20,9 @@ class BbbController < ApplicationController
   before_action :authorize_recording_owner!, only: [:update_recordings, :delete_recordings]
   before_action :load_and_authorize_room_owner!, only: [:end]
 
+  skip_before_action :verify_authenticity_token, only: :callback
+  before_action :validate_checksum, only: :callback
+
   # GET /:resource/:id/join
   def join
     if params[:name].blank?
@@ -39,7 +42,9 @@ class BbbController < ApplicationController
           user_is_moderator: true
         }
       end
-      options[:meeting_logout_url] = "#{request.base_url}/#{params[:resource]}/#{params[:id]}"
+      base_url = "#{request.base_url}/#{params[:resource]}/#{params[:id]}"
+      options[:meeting_logout_url] = base_url
+      options[:hook_url] = "#{base_url}/callback"
 
       bbb_res = bbb_join_url(
         params[:id],
@@ -55,6 +60,20 @@ class BbbController < ApplicationController
     end
   end
 
+  # POST /:resource/:id/callback
+  # Endpoint for webhook calls from BigBlueButton
+  def callback
+    begin
+      data = JSON.parse(read_body(request))
+      treat_callback_event(data["event"])
+    rescue Exception => e
+      logger.error "Error parsing webhook data. Data: #{data}, exception: #{e.inspect}"
+
+      # respond with 200 anyway so BigBlueButton knows the hook call was ok
+      render head(:ok)
+    end
+  end
+
   # DELETE /rooms/:id/end
   def end
     load_and_authorize_room_owner!
@@ -130,4 +149,61 @@ class BbbController < ApplicationController
     @response = response
     render status: @status
   end
+
+  def read_body(request)
+    request.body.read.force_encoding("UTF-8")
+  end
+
+  def treat_callback_event(event)
+
+    # a recording is ready
+    if event['header']['name'] == "publish_ended"
+      token = event['payload']['metadata'][META_TOKEN]
+      record_id = event['payload']['meeting_id']
+
+      # the webhook event doesn't have all the data we need, so we need
+      # to send a getRecordings anyway
+      # TODO: if the webhooks included all data we wouldn't need this
+      rec_info = bbb_get_recordings(token, record_id)
+      rec_info = rec_info[:recordings].first
+      RecordingCreatedJob.perform_later(token, parse_recording_for_view(rec_info))
+    end
+
+    render head(:ok) && return
+  end
+
+  # Validates the checksum received in a callback call.
+  # If the checksum doesn't match, renders an ok and aborts execution.
+  def validate_checksum
+    secret = ENV['BIGBLUEBUTTON_SECRET']
+    checksum = params["checksum"]
+    data = read_body(request)
+    callback_url = uri_remove_param(request.url, "checksum")
+
+    checksum_str = "#{callback_url}#{data}#{secret}"
+    calculated_checksum = Digest::SHA1.hexdigest(checksum_str)
+
+    if calculated_checksum != checksum
+      logger.error "Checksum did not match. Calculated: #{calculated_checksum}, received: #{checksum}"
+
+      # respond with 200 anyway so BigBlueButton knows the hook call was ok
+      # but abort execution
+      render head(:ok) && return
+    end
+  end
+
+  # Removes parameters from an URI
+  def uri_remove_param(uri, params = nil)
+    return uri unless params
+    params = Array(params)
+    uri_parsed = URI.parse(uri)
+    return uri unless uri_parsed.query
+    new_params = uri_parsed.query.gsub(/&amp;/, '&').split('&').reject { |q| params.include?(q.split('=').first) }
+    uri = uri.split('?').first
+    if new_params.count > 0
+      "#{uri}?#{new_params.join('&')}"
+    else
+      uri
+    end
+  end
 end

app/jobs/recording_created_job.rb

@@ -0,0 +1,26 @@
+# BigBlueButton open source conferencing system - http://www.bigbluebutton.org/.
+#
+# Copyright (c) 2016 BigBlueButton Inc. and by respective authors (see below).
+#
+# This program is free software; you can redistribute it and/or modify it under the
+# terms of the GNU Lesser General Public License as published by the Free Software
+# Foundation; either version 3.0 of the License, or (at your option) any later
+# version.
+#
+# BigBlueButton is distributed in the hope that it will be useful, but WITHOUT ANY
+# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+# PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License along
+# with BigBlueButton; if not, see <http://www.gnu.org/licenses/>.
+
+class RecordingCreatedJob < ApplicationJob
+  include BbbApi
+
+  queue_as :default
+
+  def perform(room, recording)
+    ActionCable.server.broadcast "#{room}_recording_updates_channel",
+      { action: 'create' }.merge(recording)
+  end
+end

app/jobs/recording_deletes_job.rb

@@ -28,7 +28,7 @@ class RecordingDeletesJob < ApplicationJob
       if !bbb_res[:recordings] || bbb_res[:messageKey] == 'noRecordings'
         ActionCable.server.broadcast "#{room}_recording_updates_channel",
           action: 'delete',
-          record_id: record_id
+          id: record_id
         break
       end
       sleep sleep_time

app/jobs/recording_updates_job.rb

@@ -24,7 +24,7 @@ class RecordingUpdatesJob < ApplicationJob
     recording = bbb_res[:recordings].first
     ActionCable.server.broadcast "#{room}_recording_updates_channel",
       action: 'update',
-      record_id: record_id,
+      id: record_id,
       published: recording[:published],
       listed: bbb_is_recording_listed(recording)
   end

app/lib/bbb_api.rb

@@ -15,7 +15,9 @@
 # with BigBlueButton; if not, see <http://www.gnu.org/licenses/>.
 
 module BbbApi
-  META_LISTED = "greenlight-listed"
+  META_LISTED = "gl-listed"
+  META_TOKEN = "gl-token"
+  META_HOOK_URL = "gl-webhooks-callback-url"
 
   def bbb_endpoint
     Rails.configuration.bigbluebutton_endpoint || ''
@@ -53,7 +55,7 @@ module BbbApi
 
       # See if the meeting is running
       begin
-        bbb_meeting_info = bbb.get_meeting_info( meeting_id, nil )
+        bbb_meeting_info = bbb.get_meeting_info(meeting_id, nil)
       rescue BigBlueButton::BigBlueButtonException => exc
         # This means that is not created
 
@@ -72,9 +74,14 @@ module BbbApi
           logoutURL: logout_url,
           moderatorPW: moderator_password,
           attendeePW: viewer_password,
-          "meta_#{BbbApi::META_LISTED}": false
+          "meta_#{BbbApi::META_LISTED}": false,
+          "meta_#{BbbApi::META_TOKEN}": meeting_token
         }
 
+        meeting_options.merge!(
+          { "meta_#{BbbApi::META_HOOK_URL}": options[:hook_url] }
+        ) if options[:hook_url]
+
         # Create the meeting
         bbb.create_meeting(options[:meeting_name], meeting_id, meeting_options)
 
@@ -110,7 +117,7 @@ module BbbApi
       options[:recordID] = record_id
     end
     if meeting_id
-      options[:meetingID] = (Digest::SHA1.hexdigest(Rails.application.secrets[:secret_key_base]+meeting_id)).to_s
+      options[:meetingID] = bbb_meeting_id(meeting_id)
     end
     res = bbb_safe_execute :get_recordings, options
 
@@ -210,6 +217,42 @@ module BbbApi
       recording[:metadata][BbbApi::META_LISTED.to_sym] == "true"
   end
 
+  # Parses a recording as returned by getRecordings and returns it
+  # as an object as expected by the views.
+  # TODO: this is almost the same done by jbuilder templates (bbb/recordings),
+  #       how to reuse them?
+  def parse_recording_for_view(recording)
+    recording[:previews] ||= []
+    previews = recording[:previews].map do |preview|
+      {
+        url: preview[:content],
+        width: preview[:width],
+        height: preview[:height],
+        alt: preview[:alt]
+      }
+    end
+    recording[:playbacks] ||= []
+    playbacks = recording[:playbacks].map do |playback|
+      {
+        type: playback[:type],
+        type_i18n: t(playback[:type]),
+        url: playback[:url],
+        previews: previews
+      }
+    end
+    {
+      id: recording[:recordID],
+      name: recording[:name],
+      published: recording[:published],
+      end_time: recording[:endTime].to_s,
+      start_time: recording[:startTime].to_s,
+      length: recording[:length],
+      listed: recording[:listed],
+      playbacks: playbacks,
+      previews: previews
+    }
+  end
+
   def success_join_res(join_url)
     {
       returncode: true,

app/views/layouts/application.html.erb

@@ -79,4 +79,8 @@ with BigBlueButton; if not, see <http://www.gnu.org/licenses/>.
 
 <script type="text/javascript">
   window.I18n = <%= client_translations.to_json.html_safe %>
+  window.GreenLight = {};
+  window.GreenLight.META_LISTED = "<%= BbbApi::META_LISTED %>";
+  window.GreenLight.META_TOKEN = "<%= BbbApi::META_TOKEN %>";
+  window.GreenLight.META_HOOK_URL = "<%= BbbApi::META_HOOK_URL %>";
 </script>

config/locales/en-us.yml

@@ -48,6 +48,7 @@ en-US:
     no_recordings: No Recordings
     no_recordings_yet: No Recordings (Yet!)
     publish_recording: Publish recording
+    recording_created: A recording was created
     recording_deleted: Recording was deleted
     recording_published: Recording was published
     recording_unlisted: Recording was unlisted

config/routes.rb

@@ -31,6 +31,7 @@ Rails.application.routes.draw do
   get '/:resource/:id/join', to: 'bbb#join', as: :bbb_join, defaults: {format: 'json'}
   get '/:resource/:id/wait', to: 'landing#wait_for_moderator'
   get '/:resource/:id/session_status_refresh', to: 'landing#session_status_refresh'
+  post '/:resource/:id/callback', to: 'bbb#callback' #, defaults: {format: 'json'}
   delete '/rooms/:id/end', to: 'bbb#end', defaults: {format: 'json'}
   get '/rooms/:id/recordings', to: 'bbb#recordings', defaults: {format: 'json'}
   patch '/rooms/:id/recordings/:record_id', to: 'bbb#update_recordings', defaults: {format: 'json'}