Class: Admin::EventsController

Inherits:
BaseController
  • Object
show all
Includes:
ActionController::Live
Defined in:
lib/generators/open_loam/install/templates/admin/events_controller.rb

Overview

Server-Sent Events: a per-tenant push stream (OpenLoam::EventStream) so the admin updates live instead of polling. Authentication runs in the normal before_action chain (set_open_loam_context) BEFORE any stream write — so an unauthenticated request redirects to login the ordinary way, since no headers have been committed yet. Once the loop starts writing, the response is committed and there is no going back; that ordering is the whole safety of a Live action.

Constant Summary collapse

HEARTBEAT_SECONDS = 
20

Constants included from Pagination

Pagination::PER_PAGE

Instance Method Summary collapse

Methods inherited from BaseController

skip_authorization!

Methods included from Pagination

#paginate

Instance Method Details

#stream ⇒ Object 



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# File 'lib/generators/open_loam/install/templates/admin/events_controller.rb', line 16

def stream
  response.headers["Content-Type"] = "text/event-stream"
  response.headers["Cache-Control"] = "no-cache"
  handle = nil # so the ensure never raises NameError if subscribe below does
  queue = Queue.new

  # Subscribe as the FIRST thing in the begin whose ensure unsubscribes: a
  # leaked AS::Notifications subscriber would fire on every future event in
  # the process, holding this dead stream's queue forever.
  handle = OpenLoam::EventStream.broadcaster.subscribe(tenant: current_tenant, actor: current_actor) do |sse|
    queue << sse
  end

  loop do
    # A heartbeat comment both keeps the connection alive AND detects a dead
    # client: writing to a closed socket raises IOError → the loop exits →
    # ensure runs and the subscription is dropped.
    message = queue.pop(timeout: HEARTBEAT_SECONDS)
    response.stream.write(message || ": heartbeat\n\n")
  end
rescue IOError, ActionController::Live::ClientDisconnected
  # The client went away — nothing to do but clean up in `ensure`.
ensure
  OpenLoam::EventStream.broadcaster.unsubscribe(handle)
  response.stream.close
  OpenLoam::Current.reset
end