Object Identification

GraphQL-Ruby ships with some helpers to implement Relay-style object identification.

Schema methods

See the Schema definition guide for required top-level hooks.

Node interface

One requirement for Relay’s object management is implementing the "Node" interface.

To implement the node interface, add GraphQL::Types::Relay::Node to your definition:

class Types::PostType < GraphQL::Schema::Object # Implement the "Node" interface for Relay implements GraphQL::Types::Relay::Node # ... end 

To tell GraphQL how to resolve members of the Node interface, you must also define Schema.resolve_type:

class MySchema < GraphQL::Schema # You'll also need to define `resolve_type` for # telling the schema what type Relay `Node` objects are def self.resolve_type(type, obj, ctx) case obj when Post Types::PostType when Comment Types::CommentType else raise("Unexpected object: #{obj}") end end end 

UUID fields

Nodes must have a field named "id" which returns a globally unique ID.

To add a UUID field named "id", implement the GraphQL::Types::Relay::Node interface::

class Types::PostType < GraphQL::Schema::Object implements GraphQL::Types::Relay::Node end 

This field will call the previously-defined id_from_object class method.

node field (find-by-UUID)

You should also provide a root-level node field so that Relay can refetch objects from your schema. You can attach it like this:

class Types::QueryType < GraphQL::Schema::Object # Used by Relay to lookup objects by UUID: # Add `node(id: ID!) include GraphQL::Types::Relay::HasNodeField # ... end 

nodes field

You can also provide a root-level nodes field so that Relay can refetch objects by IDs:

class Types::QueryType < GraphQL::Schema::Object # Fetches a list of objects given a list of IDs # Add `nodes(ids: [ID!]!)` include GraphQL::Types::Relay::HasNodesField # ... end