canvas-lms/lib/external_feed_aggregator.rb

116 lines
3.3 KiB
Ruby

#
# Copyright (C) 2011 Instructure, Inc.
#
# This file is part of Canvas.
#
# Canvas is free software: you can redistribute it and/or modify it under
# the terms of the GNU Affero General Public License as published by the Free
# Software Foundation, version 3 of the License.
#
# Canvas 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 Affero General Public License for more
# details.
#
# You should have received a copy of the GNU Affero General Public License along
# with this program. If not, see <http://www.gnu.org/licenses/>.
#
require 'atom'
class ExternalFeedAggregator
def self.process
ExternalFeedAggregator.new.process
end
def initialize
@logger = Rails.logger
end
def process
Shackles.activate(:slave) do
start = Time.now.utc
loop do
feeds = ExternalFeed.to_be_polled(start).limit(1000).preload(context: :root_account).to_a
break if feeds.empty?
feeds.each do |feed|
Shackles.activate(:master) do
if !feed.context || feed.context.root_account.deleted?
feed.update_attribute(:refresh_at, success_wait_seconds.from_now)
next
end
process_feed(feed)
end
end
end
end
end
def parse_entries(feed, body)
begin
require 'rss/1.0'
require 'rss/2.0'
rss = RSS::Parser.parse(body, false)
raise "Invalid rss feed" unless rss
feed.title = rss.channel.title
feed.save
@logger.info("#{rss.items.length} rss items found")
entries = feed.add_rss_entries(rss)
@logger.info("#{entries.length} new entries added")
return true
rescue
begin
require 'atom'
atom = Atom::Feed.load_feed(body)
feed.title = atom.title
feed.save
@logger.info("#{atom.entries.length} atom entries found")
entries = feed.add_atom_entries(atom)
@logger.info("#{entries.length} new entries added")
return true
rescue
end
end
false
end
def process_feed(feed)
begin
@logger.info("feed found: #{feed.url}")
@logger.info('requesting entries')
require 'net/http'
response = CanvasHttp.get(feed.url)
case response
when Net::HTTPSuccess
success = parse_entries(feed, response.body)
@logger.info(success ? 'successful response' : '200 with no data returned')
feed.consecutive_failures = 0 if success
feed.update_attribute(:refresh_at, success_wait_seconds.from_now)
else
@logger.info("request failed #{response.class}")
handle_failure(feed)
end
rescue CanvasHttp::Error, CanvasHttp::RelativeUriError, Timeout::Error, SocketError, SystemCallError => e
@logger.info("request error: #{e}")
handle_failure(feed)
end
end
def handle_failure(feed)
feed.increment(:failures)
feed.increment(:consecutive_failures)
feed.update_attribute(:refresh_at, failure_wait_seconds.from_now)
end
def success_wait_seconds
Setting.get('external_feed_success_wait_seconds', 2.hours.to_s).to_f
end
def failure_wait_seconds
Setting.get('external_feed_failure_wait_seconds', 30.minutes.to_s).to_f
end
end