Class: GraphQL::Schema::Subscription

Inherits:
Resolver
  • Object
show all
Extended by:
Member::HasFields, Resolver::HasPayloadType
Defined in:
lib/graphql/schema/subscription.rb

Overview

This class can be extended to create fields on your subscription root.

It provides hooks for the different parts of the subscription lifecycle:

  • #authorized?: called before initial subscription and subsequent updates
  • #subscribe: called for the initial subscription
  • #update: called for subsequent update

Also, #unsubscribe terminates the subscription.

Defined Under Namespace

Classes: EarlyTerminationError, NoUpdateError, UnsubscribedError

Constant Summary collapse

READING_SCOPE =

Call this method to provide a new subscription_scope; OR call it without an argument to get the subscription_scope

Returns:

  • (Symbol) 
::Object.new

Constants included from Member::GraphQLTypeNames

Member::GraphQLTypeNames::Boolean, Member::GraphQLTypeNames::ID, Member::GraphQLTypeNames::Int

Instance Attribute Summary

Attributes inherited from Resolver

#context, #object

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Member::HasFields

add_field, field, field_class, fields, get_field, global_id_field, own_fields

Methods included from Resolver::HasPayloadType

field_class, object_class, payload_type

Methods inherited from Resolver

argument, arguments_loads_as_type, #authorized?, complexity, extras, null, #ready?, resolve_method, #resolve_with_support, type, type_expr

Methods included from Member::HasPath

#path

Methods included from Member::HasArguments

#add_argument, #argument, #argument_class, #argument_with_loads, #arguments, #own_arguments

Methods included from Member::BaseDSLMethods

#accessible?, #authorized?, #default_graphql_name, #description, #graphql_name, #introspection, #introspection?, #mutation, #name, #overridden_graphql_name, #to_graphql, #visible?

Constructor Details

#initialize(object:, context:) ⇒ Subscription

Returns a new instance of Subscription



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# File 'lib/graphql/schema/subscription.rb', line 32

def initialize(object:, context:)
  super
  # Figure out whether this is an update or an initial subscription
  @mode = context.query.subscription_update? ? :update : :subscribe
end

Class Method Details

.field_options ⇒ Object

Overriding Resolver#field_options to include subscription_scope



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# File 'lib/graphql/schema/subscription.rb', line 112

def self.field_options
  super.merge(
    subscription_scope: subscription_scope
  )
end

.subscription_scope(new_scope = READING_SCOPE) ⇒ Object 



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# File 'lib/graphql/schema/subscription.rb', line 101

def self.subscription_scope(new_scope = READING_SCOPE)
  if new_scope != READING_SCOPE
    @subscription_scope = new_scope
  elsif defined?(@subscription_scope)
    @subscription_scope
  else
    find_inherited_method(:subscription_scope, nil)
  end
end

Instance Method Details

#load_application_object_failed(err) ⇒ Object

If an argument is flagged with loads: and no object is found for it, remove this subscription (assuming that the object was deleted in the meantime, or that it became inaccessible).



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# File 'lib/graphql/schema/subscription.rb', line 84

def load_application_object_failed(err)
  if @mode == :update
    unsubscribe
  end
  super
end

#resolve(**args) ⇒ Object

Implement the Resolve API



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# File 'lib/graphql/schema/subscription.rb', line 39

def resolve(**args)
  # Dispatch based on `@mode`, which will raise a `NoMethodError` if we ever
  # have an unexpected `@mode`
  public_send("resolve_#{@mode}", args)
end

#resolve_subscribe(args) ⇒ Object

Wrap the user-defined #subscribe hook



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# File 'lib/graphql/schema/subscription.rb', line 46

def resolve_subscribe(args)
  ret_val = args.any? ? subscribe(args) : subscribe
  if ret_val == :no_response
    context.skip
  else
    ret_val
  end
end

#resolve_update(args) ⇒ Object

Wrap the user-provided #update hook



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# File 'lib/graphql/schema/subscription.rb', line 65

def resolve_update(args)
  ret_val = args.any? ? update(args) : update
  if ret_val == :no_update
    raise NoUpdateError
  else
    ret_val
  end
end

#subscribe(args = {}) ⇒ Object

Default implementation returns the root object. Override it to return an object or :no_response to return nothing.

The default is :no_response.



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# File 'lib/graphql/schema/subscription.rb', line 60

def subscribe(args = {})
  :no_response
end

#unsubscribe ⇒ Object

Call this to halt execution and remove this subscription from the system

Raises:



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# File 'lib/graphql/schema/subscription.rb', line 92

def unsubscribe
  raise UnsubscribedError
end

#update(args = {}) ⇒ Object

The default implementation returns the root object. Override it to return :no_update if you want to skip updates sometimes. Or override it to return a different object.



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# File 'lib/graphql/schema/subscription.rb', line 77

def update(args = {})
  object
end