1 files changed, 22 insertions, 14 deletions
diff --git a/actioncable/lib/action_cable/connection/subscriptions.rb b/actioncable/lib/action_cable/connection/subscriptions.rb
index 3742f248d1..bb8d64e27a 100644
--- a/actioncable/lib/action_cable/connection/subscriptions.rb
+++ b/actioncable/lib/action_cable/connection/subscriptions.rb
@@ -1,4 +1,6 @@
-require 'active_support/core_ext/hash/indifferent_access'
+# frozen_string_literal: true
+
+require "active_support/core_ext/hash/indifferent_access"
 
 module ActionCable
   module Connection
@@ -11,33 +13,37 @@ module ActionCable
       end
 
       def execute_command(data)
-        case data['command']
-        when 'subscribe'   then add data
-        when 'unsubscribe' then remove data
-        when 'message'     then perform_action data
+        case data["command"]
+        when "subscribe"   then add data
+        when "unsubscribe" then remove data
+        when "message"     then perform_action data
         else
           logger.error "Received unrecognized command in #{data.inspect}"
         end
       rescue Exception => e
-        logger.error "Could not execute command from #{data.inspect}) [#{e.class} - #{e.message}]: #{e.backtrace.first(5).join(" | ")}"
+        logger.error "Could not execute command from (#{data.inspect}) [#{e.class} - #{e.message}]: #{e.backtrace.first(5).join(" | ")}"
       end
 
       def add(data)
-        id_key = data['identifier']
+        id_key = data["identifier"]
         id_options = ActiveSupport::JSON.decode(id_key).with_indifferent_access
 
-        subscription_klass = connection.server.channel_classes[id_options[:channel]]
+        return if subscriptions.key?(id_key)
+
+        subscription_klass = id_options[:channel].safe_constantize
 
-        if subscription_klass
-          subscriptions[id_key] ||= subscription_klass.new(connection, id_key, id_options)
+        if subscription_klass && ActionCable::Channel::Base >= subscription_klass
+          subscription = subscription_klass.new(connection, id_key, id_options)
+          subscriptions[id_key] = subscription
+          subscription.subscribe_to_channel
         else
-          logger.error "Subscription class not found (#{data.inspect})"
+          logger.error "Subscription class not found: #{id_options[:channel].inspect}"
         end
       end
 
       def remove(data)
         logger.info "Unsubscribing from channel: #{data['identifier']}"
-        remove_subscription subscriptions[data['identifier']]
+        remove_subscription find(data)
       end
 
       def remove_subscription(subscription)
@@ -46,7 +52,7 @@ module ActionCable
       end
 
       def perform_action(data)
-        find(data).perform_action ActiveSupport::JSON.decode(data['data'])
+        find(data).perform_action ActiveSupport::JSON.decode(data["data"])
       end
 
       def identifiers
@@ -57,6 +63,8 @@ module ActionCable
         subscriptions.each { |id, channel| remove_subscription(channel) }
       end
 
+      # TODO Change this to private once we've dropped Ruby 2.2 support.
+      # Workaround for Ruby 2.2 "private attribute?" warning.
       protected
         attr_reader :connection, :subscriptions
 
@@ -64,7 +72,7 @@ module ActionCable
         delegate :logger, to: :connection
 
         def find(data)
-          if subscription = subscriptions[data['identifier']]
+          if subscription = subscriptions[data["identifier"]]
             subscription
           else
             raise "Unable to find subscription with identifier: #{data['identifier']}"