diff options
Diffstat (limited to 'actioncable/lib/action_cable/subscription_adapter/postgresql.rb')
-rw-r--r-- | actioncable/lib/action_cable/subscription_adapter/postgresql.rb | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/actioncable/lib/action_cable/subscription_adapter/postgresql.rb b/actioncable/lib/action_cable/subscription_adapter/postgresql.rb new file mode 100644 index 0000000000..66c7852f6e --- /dev/null +++ b/actioncable/lib/action_cable/subscription_adapter/postgresql.rb @@ -0,0 +1,107 @@ +gem 'pg', '~> 0.18' +require 'pg' +require 'thread' + +module ActionCable + module SubscriptionAdapter + class PostgreSQL < Base # :nodoc: + def initialize(*) + super + @listener = nil + end + + def broadcast(channel, payload) + with_connection do |pg_conn| + pg_conn.exec("NOTIFY #{pg_conn.escape_identifier(channel)}, '#{pg_conn.escape_string(payload)}'") + end + end + + def subscribe(channel, callback, success_callback = nil) + listener.add_subscriber(channel, callback, success_callback) + end + + def unsubscribe(channel, callback) + listener.remove_subscriber(channel, callback) + end + + def shutdown + listener.shutdown + end + + def with_connection(&block) # :nodoc: + ActiveRecord::Base.connection_pool.with_connection do |ar_conn| + pg_conn = ar_conn.raw_connection + + unless pg_conn.is_a?(PG::Connection) + raise 'ActiveRecord database must be Postgres in order to use the Postgres ActionCable storage adapter' + end + + yield pg_conn + end + end + + private + def listener + @listener || @server.mutex.synchronize { @listener ||= Listener.new(self, @server.event_loop) } + end + + class Listener < SubscriberMap + def initialize(adapter, event_loop) + super() + + @adapter = adapter + @event_loop = event_loop + @queue = Queue.new + + @thread = Thread.new do + Thread.current.abort_on_exception = true + listen + end + end + + def listen + @adapter.with_connection do |pg_conn| + catch :shutdown do + loop do + until @queue.empty? + action, channel, callback = @queue.pop(true) + + case action + when :listen + pg_conn.exec("LISTEN #{pg_conn.escape_identifier channel}") + @event_loop.post(&callback) if callback + when :unlisten + pg_conn.exec("UNLISTEN #{pg_conn.escape_identifier channel}") + when :shutdown + throw :shutdown + end + end + + pg_conn.wait_for_notify(1) do |chan, pid, message| + broadcast(chan, message) + end + end + end + end + end + + def shutdown + @queue.push([:shutdown]) + Thread.pass while @thread.alive? + end + + def add_channel(channel, on_success) + @queue.push([:listen, channel, on_success]) + end + + def remove_channel(channel) + @queue.push([:unlisten, channel]) + end + + def invoke_callback(*) + @event_loop.post { super } + end + end + end + end +end |