instance method
subscribe
Ruby on Rails edge
Since v8.1.4Available in: v8.1.4 edge
Signature
subscribe(subscriber, &filter)Registers a new event subscriber. The subscriber must respond to
“‘ emit(event: Hash) “`
The event hash will have the following keys:
“‘ name: String (The name of the event) payload: Hash, Object (The payload of the event, or the event object itself) tags: Hash (The tags of the event) context: Hash (The context of the event) timestamp: Integer (The timestamp of the event, in nanoseconds) source_location: Hash (The source location of the event, containing the filepath, lineno, and label) “`
The event hash and its payload hash are frozen. Subscribers that need to modify them should dup them first.
An optional filter proc can be provided to only receive a subset of events:
“‘ Rails.event.subscribe(subscriber) { |event| event.start_with?(“user.”) } “`
Only the :name key is available to filters, not the entire payload.
Parameters
-
subscriberreq -
filterblock
Source
# File activesupport/lib/active_support/event_reporter.rb, line 351
def subscribe(subscriber, &filter)
unless subscriber.respond_to?(:emit)
raise ArgumentError, "Event subscriber #{subscriber.class.name} must respond to #emit"
end
@subscribers << { subscriber: subscriber, filter: filter }
end
Defined in activesupport/lib/active_support/event_reporter.rb line 351
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Defined in ActiveSupport::EventReporter