Class: SessionChannel

Inherits:
ApplicationCable::Channel show all
Defined in:
app/channels/session_channel.rb

Overview

Streams events for a specific session to connected clients. Part of the Brain/TUI separation: the Brain broadcasts events through this channel, and any number of clients (TUI, web, API) can subscribe.

On subscription, sends the session’s chat history so the client can render previous messages without a separate API call.

Examples:

Client subscribes to a session

App.cable.subscriptions.create({ channel: "SessionChannel", session_id: 42 })

Constant Summary collapse

DEFAULT_LIST_LIMIT = 
10
MAX_LIST_LIMIT = 
50

Instance Method Summary collapse

Instance Method Details

#change_view_mode(data) ⇒ Object

Changes the session’s view mode and re-broadcasts the viewport. All clients on the session receive the mode change and fresh history.

Parameters:

  • data (Hash) —

    must include “view_mode” (one of Session::VIEW_MODES)



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# File 'app/channels/session_channel.rb', line 168

def change_view_mode(data)
  mode = data["view_mode"].to_s
  return transmit_error("Invalid view mode") unless Session::VIEW_MODES.include?(mode)

  session = Session.find(@current_session_id)
  session.update!(view_mode: mode)

  ActionCable.server.broadcast(stream_name, {"action" => "view_mode_changed", "view_mode" => mode})
  broadcast_viewport(session)
rescue ActiveRecord::RecordNotFound
  transmit_error("Session not found")
end

#create_session(_data) ⇒ Object

Creates a new session and switches the channel stream to it. The client receives a session_changed signal followed by (empty) history.



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# File 'app/channels/session_channel.rb', line 121

def create_session(_data)
  session = Session.create!
  switch_to_session(session.id)
end

#interrupt_execution(_data) ⇒ Object

Requests interruption of the current tool execution. Sets a flag on the session that the LLM client checks between tool calls. Remaining tools receive synthetic “Stopped by user” results to satisfy the API’s tool_use/tool_result pairing requirement.

Atomic: a single UPDATE with WHERE avoids the read-then-write race where the session could finish processing between the SELECT and UPDATE. No-op if the session isn’t currently processing.

Parameters:

  • _data (Hash) —

    unused



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# File 'app/channels/session_channel.rb', line 99

def interrupt_execution(_data)
  Session.where(id: @current_session_id, processing: true)
    .update_all(interrupt_requested: true)
end

#list_sessions(data) ⇒ Object

Returns recent root sessions with nested child metadata for session picker UI. Filters to root sessions only (no parent_session_id). Child sessions are nested under their parent with name and status information.

Parameters:

  • data (Hash) —

    optional “limit” (default 10, max 50)



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# File 'app/channels/session_channel.rb', line 109

def list_sessions(data)
  limit = (data["limit"] || DEFAULT_LIST_LIMIT).to_i.clamp(1, MAX_LIST_LIMIT)
  sessions = Session.root_sessions.recent(limit).includes(:child_sessions)
  all_ids = sessions.flat_map { |session| [session.id] + session.child_sessions.map(&:id) }
  counts = Event.where(session_id: all_ids).llm_messages.group(:session_id).count

  result = sessions.map { |session| serialize_session_with_children(session, counts) }
  transmit({"action" => "sessions_list", "sessions" => result})
end

#recall_pending(data) ⇒ Object

Recalls the most recent pending message for editing. Deletes the pending event and broadcasts the recall so all clients remove it.

Parameters:

  • data (Hash) —

    must include “event_id” (positive integer)



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# File 'app/channels/session_channel.rb', line 73

def recall_pending(data)
  event_id = data["event_id"].to_i
  return if event_id <= 0

  event = Event.find_by(
    id: event_id,
    session_id: @current_session_id,
    event_type: "user_message",
    status: Event::PENDING_STATUS
  )
  return unless event

  event.destroy!
  ActionCable.server.broadcast(stream_name, {"action" => "user_message_recalled", "event_id" => event_id})
end

#receive(data) ⇒ Object

Receives messages from clients and broadcasts them to all session subscribers.

Parameters:

  • data (Hash) —

    arbitrary message payload



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# File 'app/channels/session_channel.rb', line 41

def receive(data)
  ActionCable.server.broadcast(stream_name, data)
end

#save_token(data) ⇒ Object

Validates and saves an Anthropic subscription token to encrypted credentials. Format-validated and API-validated before storage. The token never enters the LLM context window — it flows directly from WebSocket to encrypted credentials.

Parameters:

  • data (Hash) —

    must include “token” (Anthropic subscription token string)



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# File 'app/channels/session_channel.rb', line 144

def save_token(data)
  token = data["token"].to_s.strip

  Providers::Anthropic.validate_token_format!(token)

  warning = begin
    Providers::Anthropic.validate_token_api!(token)
    nil
  rescue Providers::Anthropic::TransientError => transient
    # Token format is valid but API is temporarily unavailable (500, timeout, etc.).
    # Save the token to break the prompt loop — it will work once the API recovers.
    "Token saved but could not be verified — #{transient.message}"
  end

  write_anthropic_token(token)
  transmit({"action" => "token_saved", "warning" => warning}.compact)
rescue Providers::Anthropic::TokenFormatError, Providers::Anthropic::AuthenticationError => error
  transmit({"action" => "token_error", "message" => error.message})
end

#speak(data) ⇒ Object

Processes user input. For idle sessions, persists the event immediately so the message appears in the TUI without waiting for the background job, then schedules AgentRequestJob for LLM delivery. If delivery fails, the job deletes the event and emits a Events::BounceBack.

For busy sessions, emits a pending Events::UserMessage that queues until the current agent loop completes.

Parameters:

  • data (Hash) —

    must include “content” with the user’s message text



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# File 'app/channels/session_channel.rb', line 54

def speak(data)
  content = data["content"].to_s.strip
  return if content.empty?

  session = Session.find_by(id: @current_session_id)
  return unless session

  if session.processing?
    Events::Bus.emit(Events::UserMessage.new(content: content, session_id: @current_session_id, status: Event::PENDING_STATUS))
  else
    event = session.create_user_event(content)
    AgentRequestJob.perform_later(session.id, event_id: event.id)
  end
end

#subscribed ⇒ Object

Subscribes the client to the session-specific stream. When a valid session_id is provided, subscribes to that session. When omitted or zero, resolves to the most recent session (creating one if none exist) — this is the CQRS-compliant path where the server owns session resolution instead of a REST endpoint.

Always transmits a session_changed signal so the client learns the authoritative session ID, followed by view_mode and history.

Parameters:

  • params (Hash) —

    optional :session_id (positive integer)



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# File 'app/channels/session_channel.rb', line 26

def subscribed
  @current_session_id = resolve_session_id
  stream_from stream_name

  session = Session.find_by(id: @current_session_id)
  return unless session

  transmit_session_changed(session)
  transmit_view_mode(session)
  transmit_history(session)
end

#switch_session(data) ⇒ Object

Switches the channel stream to an existing session. The client receives a session_changed signal followed by chat history.

Parameters:

  • data (Hash) —

    must include “session_id” (positive integer)



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# File 'app/channels/session_channel.rb', line 130

def switch_session(data)
  target_id = data["session_id"].to_i
  return transmit_error("Session not found") unless target_id > 0

  switch_to_session(target_id)
rescue ActiveRecord::RecordNotFound
  transmit_error("Session not found")
end