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author | Jon Moss <me@jonathanmoss.me> | 2016-01-15 19:07:18 -0500 |
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committer | Jon Moss <me@jonathanmoss.me> | 2016-01-18 18:59:30 -0500 |
commit | 4c5d5b75abe85d59e5cc9de9904fdef3b23ec25b (patch) | |
tree | 63a2b21cdcf1a411d8babc260448fa0a32e0d266 /actioncable/lib/action_cable/subscription_adapter/postgresql.rb | |
parent | 6aeaed4c1a370084e82c6712a32422a58dac8b8c (diff) | |
download | rails-4c5d5b75abe85d59e5cc9de9904fdef3b23ec25b.tar.gz rails-4c5d5b75abe85d59e5cc9de9904fdef3b23ec25b.tar.bz2 rails-4c5d5b75abe85d59e5cc9de9904fdef3b23ec25b.zip |
ActionCable::StorageAdapter ==> ActionCable::SubscriptionAdapter
Diffstat (limited to 'actioncable/lib/action_cable/subscription_adapter/postgresql.rb')
-rw-r--r-- | actioncable/lib/action_cable/subscription_adapter/postgresql.rb | 101 |
1 files changed, 101 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..f55b56a2b5 --- /dev/null +++ b/actioncable/lib/action_cable/subscription_adapter/postgresql.rb @@ -0,0 +1,101 @@ +require 'thread' + +begin + require 'pg' +rescue Gem::LoadError => e + raise Gem::LoadError, "You are trying to use the PostgreSQL ActionCable adapter, but do not have the proper gems installed. Add `gem 'pg'` to your Gemfile (and ensure its version is at the minimum required by ActionCable)." +end + +module ActionCable + module SubscriptionAdapter + class PostgreSQL < Base + # The storage instance used for broadcasting. Not intended for direct user use. + def broadcast(channel, payload) + with_connection do |pg_conn| + pg_conn.exec("NOTIFY #{channel}, '#{payload}'") + end + end + + def subscribe(channel, callback, success_callback = nil) + listener.subscribe_to(channel, callback, success_callback) + end + + def unsubscribe(channel, callback) + listener.unsubscribe_to(channel, callback) + 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 ||= Listener.new(self) + end + + class Listener + def initialize(adapter) + @adapter = adapter + @subscribers = Hash.new { |h,k| h[k] = [] } + @sync = Mutex.new + @queue = Queue.new + + Thread.new do + Thread.current.abort_on_exception = true + listen + end + end + + def listen + @adapter.with_connection do |pg_conn| + loop do + until @queue.empty? + value = @queue.pop(true) + if value.first == :listen + pg_conn.exec("LISTEN #{value[1]}") + ::EM.next_tick(&value[2]) if value[2] + elsif value.first == :unlisten + pg_conn.exec("UNLISTEN #{value[1]}") + end + + pg_conn.wait_for_notify(1) do |chan, pid, message| + @subscribers[chan].each do |callback| + ::EM.next_tick { callback.call(message) } + end + end + end + end + end + end + + def subscribe_to(channel, callback, success_callback) + @sync.synchronize do + if @subscribers[channel].empty? + @queue.push([:listen, channel, success_callback]) + end + + @subscribers[channel] << callback + end + end + + def unsubscribe_to(channel, callback) + @sync.synchronize do + @subscribers[channel].delete(callback) + + if @subscribers[channel].empty? + @queue.push([:unlisten, channel]) + end + end + end + end + end + end +end |