abstract class Amber::WebSockets::Channel

• Amber::WebSockets::Channel
• Reference
• Object

Overview

Sockets subscribe to Channels, where the communication log is handled. The channel provides functionality to handle socket join #handle_joined and socket messages handle_message(msg).

Example:

class ChatChannel < Amber::WebSockets::Channel
  def handle_joined(client_socket, message)
    # functionality when the user joins the channel, optional
  end

  def handle_leave(client_socket)
    # functionality when the user leaves the channel, optional
  end

  def after_join(client_socket)
    # called after handle_joined completes, optional
  end

  def after_leave(client_socket)
    # called after handle_leave completes, optional
  end

  def on_error(ex, client_socket)
    # called when an error occurs during message handling, optional
  end

  # functionality when a socket sends a message to a channel, required
  def handle_message(client_socket, msg)
    rebroadcast!(msg)
  end
end

Defined in:

Constant Summary

Log = ::Log.for(self)

Constructors

• .new(topic_path : String)

Class Method Summary

• .broadcast_to(channel_topic : String, event : String, payload : Hash(String, String))

  Broadcasts a message to all subscribers of the given topic from outside a channel instance.

• .on_message(topic_path : String, client_socket_id : String, message : JSON::Any)

  Called from proc when message is returned from the pubsub service This is a class method that handles message dispatch to instances

• .presence_list(topic_path : String) : Hash(String, Hash(String, String))

  Class-level access to presence data for a given topic.

• .reset_presence

  Resets presence tracking.

Instance Method Summary

• #after_join(client_socket)

  Called after #handle_joined completes successfully.

• #after_leave(client_socket)

  Called after #handle_leave completes successfully.

• #broadcast!(message, topic = @topic_path)

  Sends message to all subscribing clients belonging to this channel by using the rebroadcast functionality that sends to all subscribers

• #handle_joined(client_socket, message)

  Authorization can happen here

• #handle_leave(client_socket)
• #handle_message(client_socket, msg)
• #on_error(ex : Exception, client_socket)

  Called when an error occurs during message handling or channel callbacks.

• #presence_count : Int32

  Returns the number of sockets currently present in this channel's topic.

• #presence_list : Hash(String, Hash(String, String))

  Returns the list of currently present sockets in this channel's topic.

• #rebroadcast!(message, topic = @topic_path)
• #subscribe_to_channel(client_socket, message)

  Called when a socket subscribes to a channel

• #unsubscribe_from_channel(client_socket)

  Called when a socket unsubscribes from a channel

Constructor Detail

Class Method Detail

# From a controller action:
ChatChannel.broadcast_to("chat_room:lobby", "msg:new", {"message" => "Server announcement"})

Instance Method Detail