Extending the schema#

Adding a custom model#

The only point of contact the silverstripe/graphql schema has with the Silverstripe ORM specifically is through the DataObjectModel adapter and its associated plugins. This is important, because it means you can plug in any schema-aware class as a model, and it will be afforded all the same features as DataObjects.

It is, however, hard to imagine a model-driven type that isn't related to an ORM, so we'll keep this section simple and just describe what the requirements are rather than think up an outlandish example of what a non-DataObject model might be.

SchemaModelInterface#

Models must implement the SchemaModelInterface, which has a lot of methods to implement. Let's walk through them:

• getIdentifier(): string: A unique identifier for this model type, e.g. DataObject
• hasField(string $fieldName): bool: Return true if $fieldName exists on the model
• getTypeForField(string $fieldName): ?string: Given a field name, infer the type. If the field doesn't exist, return null
• getTypeName(): string: Get the name of the type (i.e. based on the source class)
• getDefaultResolver(?array $context = []): ResolverReference: Get the generic resolver that should be used for types that are built with this model.
• getSourceClass(): string: Get the name of the class that builds the type, e.g. MyDataObject
• getAllFields(): array: Get all available fields on the object
• getModelField(string $fieldName): ?ModelType: For nested fields. If a field resolves to another model (e.g. has_one), return that model type.

In addition, models may want to implement:

• OperationProvider (if your model creates operations, like read, create, etc)
• DefaultFieldsProvider (if your model provides a default list of fields, e.g. id)

This is all a lot to take in out of context. A good exercise would be to look through how DataObjectModel implements all these methods.

SchemaModelCreatorInterface#

Given a class name, create an instance of SchemaModelCreatorInterface. This layer of abstraction is necessary because we can't assume that all implementations of SchemaModelCreatorInterface will accept a class name in their constructors.

Implementors of this interface just need to be able to report whether they apply to a given class and create a model given a class name.

Look at the ModelCreator implementation for a good example of how this works.

Registering your model creator#

Just add it to the registry:

# app/_graphql/config.yml
modelCreators:
  - 'SilverStripe\GraphQL\Schema\DataObject\ModelCreator'

Further reading#