Method: ActiveSupport::Notifications.subscribe

Defined in:
lib/active_support/notifications.rb

.subscribe(pattern = nil, callback = nil, &block) ⇒ Object

Subscribe to a given event name with the passed block.

You can subscribe to events by passing a String to match exact event names, or by passing a Regexp to match all events that match a pattern.

ActiveSupport::Notifications.subscribe(/render/) do |*args|
  @event = ActiveSupport::Notifications::Event.new(*args)
end

The block will receive five parameters with information about the event:

ActiveSupport::Notifications.subscribe('render') do |name, start, finish, id, payload|
  name    # => String, name of the event (such as 'render' from above)
  start   # => Time, when the instrumented block started execution
  finish  # => Time, when the instrumented block ended execution
  id      # => String, unique ID for the instrumenter that fired the event
  payload # => Hash, the payload
end

If the block passed to the method only takes one parameter, it will yield an event object to the block:

ActiveSupport::Notifications.subscribe(/render/) do |event|
  @event = event
end



234
235
236
 
# File 'lib/active_support/notifications.rb', line 234

def subscribe(pattern = nil, callback = nil, &block)
  notifier.subscribe(pattern, callback, monotonic: false, &block)
end