Faye Online user list and time count

Usage

1. Add it to Gemfile

gem 'faye-online'

2. add faye related table

bundle exec rake db:migrate

3. faye server

Create a faye.ru at your rails app root, configure it,

$faye_server = FayeOnline.get_server(:host=>"localhost",
                                     :port=>6379,
                                     :database=>1,
                                     :namespace=>"faye",
                                     :gc=>5)
run $faye_server

and start faye server

bundle exec rake faye:start
DEBUG_FAYE=true DEBUG=true bundle exec rackup faye.ru -s thin -E production -p 9292

4. faye client

init faye client

eoe.faye = Faye.init_online_client({
  faye_url: faye_url,
  client_opts: {},
  auth_opts: {
    room_channel: eoe.class_channel,
    time_channel: eoe.lesson_channel,
    current_user: eoe.current_user
  }
});

subscribe user_list channel

eoe.faye.subscribe(eoe.class_channel + '/user_list', function (message) {
  console.log(message.count, message.user_list);
})

Data Storage Stucture

• mysql.table.faye_channels channel name to id, use for key value cache.
• mysql.table.faye_channel_online_lists online user list, store as Set data structure, add and delete.
• mysql.table.faye_user_online_times user online time, store every start time and spend time.
• mysql.table.faye_user_login_logs verbose user login log, used for caculate online times alternately.
• .
• redis.hashes.ns/uid_to_clientids/room_channel all clientids of one uid in a room_channel
• redis.hashes.ns/uid_to_clientids/time_channel all clientids of one uid in a time_channel
• redis.keys.ns/clientid_auth/clientid map clientid to user info
• redis.keys.ns/clientid_status/clientid current clientid is login or logout

Glossary of Terms

clientId

客户端(一般是浏览器里的javascript)连到服务器后自动分配一个clientId。 示例数据为:

{
  "channel"=>"/meta/connect",
  "clientId"=>"sqq4oxlwhj84zw92n0e592j8iq989yy",
  "id"=>"7",
  "auth"=>{
    "room_channel"=>"/classes/4",
    "time_channel"=>"/courses/5/lessons/1",
    "current_user"=>{"uid"=>470700, "uname"=>"mvj3"}
  }
}

User Login

有很多个clientId连到server。其中可能多个clientId关联的是一个user，这个在 Faye.init_online_client 可以配置。

User Logout

一个user关联的所有clientId失去连接后才算离线。 server判断一个user离开房间的两种机制:

1. client端主动触发disconnect发消息，对于的实际操作是关闭所有相关页面。

2. 网络掉线。在 FayeOnline.get_server 设置gc参数让server端定时ping所有的clientId，具体方法在faye-redis-ruby.gem里的 EventMachine.add_periodic_timer(gc, &method(:gc)) 。如果检测是失去连接，那么server就给自己发个伪装的disconnect消息，从而清理失去网络连接的clientId。

改进的客户端autodisconnect

原来的情况

在用户关闭浏览器前触发一个"/meta/disconnect"请求。这样如果用户否定关闭后，client对象却还是被销毁了。

改进的方案

在浏览器关闭前，发送给server一个过几秒后检测当前clientId是否失去连接的事件。

1, 这样如果浏览器真的关掉了，那就和原来的autodisconnect发送的"/meta/disconnect"消息一样。

2, 如果浏览器被用户选择否定关掉，那浏览器里的client对象还是没被销毁，而继续存活。

具体见对lib/faye-online/message.rb里对 /faye_online/before_leave 的基于EventMachine的定时器处理。

TODO

1. FayeOnline.faye_online_status 通用化
2. Cluster front end https://github.com/alexkazeko/faye_shards
3. use rainbows server, see faye-websocket README。一些尝试见rainbows.conf, https://groups.google.com/forum/#!msg/faye-users/cMPhvIpk-OU/MgRcFhmz8koJ
4. 英文化

Related Resources

1. https://github.com/ryanb/private_pub Private Pub is a Ruby gem for use with Rails to publish and subscribe to messages through Faye. It allows you to easily provide real-time updates through an open socket without tying up a Rails process. All channels are private so users can only listen to events you subscribe them to.

2. http://blog.edweng.com/2012/06/02/faye-extensions-tracking-users-in-a-chat-room/ only track clientId

3. http://faye.jcoglan.com/ruby/monitoring.html tech detail about track connect and disconnect in faye