Method: GraphQL::Schema::Subscription.topic_for

Defined in:
lib/graphql/schema/subscription.rb

.topic_for(arguments:, field:, scope:) ⇒ String

This is called during initial subscription to get a "name" for this subscription. Later, when .trigger is called, this will be called again to build another "name". Any subscribers with matching topic will begin the update flow.

The default implementation creates a string using the field name, subscription scope, and argument keys and values. In that implementation, only .trigger calls with exact matches result in updates to subscribers.

To implement a filtered stream-type subscription flow, override this method to return a string with field name and subscription scope. Then, implement #update to compare its arguments to the current object and return NO_UPDATE when an update should be filtered out.

Parameters:

  • arguments (Hash<String => Object>) —

    The arguments for this topic, in GraphQL-style (camelized strings)

  • field (GraphQL::Schema::Field)
  • scope (Object, nil) —

    A value corresponding to .trigger(... scope:) (for updates) or the subscription_scope found in context (for initial subscriptions).

Returns:

  • (String) —

    An identifier corresponding to a stream of updates

See Also:

  • for how to skip updates when an event comes with a matching topic.


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# File 'lib/graphql/schema/subscription.rb', line 160

def self.topic_for(arguments:, field:, scope:)
  Subscriptions::Serialize.dump_recursive([scope, field.graphql_name, arguments])
end