Method subjectFilter

internal/engines/subject_filter.go:88–132

subjectFilter is a method for the SubjectFilterEngine struct. It determines the type of relational reference for the permission field in the request, prepares and returns a SubjectFilterFunction accordingly.

(
	ctx context.Context,
	request *base.PermissionLookupSubjectRequest,
	en *base.EntityDefinition,
)

// It determines the type of relational reference for the permission field in the request,
// prepares and returns a SubjectFilterFunction accordingly.
func (engine *SubjectFilter) subjectFilter(
	ctx context.Context,
	request *base.PermissionLookupSubjectRequest,
	en *base.EntityDefinition,
) SubjectFilterFunction {
	// The GetTypeOfRelationalReferenceByNameInEntityDefinition method retrieves the type of relational reference for the permission field.
	tor, _ := schema.GetTypeOfReferenceByNameInEntityDefinition(en, request.GetPermission())

	var fn SubjectFilterFunction

	switch tor {
	case base.EntityDefinition_REFERENCE_PERMISSION:
		// Get the permission by its name in the entity definition.
		permission, err := schema.GetPermissionByNameInEntityDefinition(en, request.GetPermission())
		if err != nil {
			// If an error is encountered while getting the permission, a SubjectFilterFunction is returned that always fails with this error.
			return subjectFilterFail(err)
		}
		child := permission.GetChild()

		// Depending on whether the child permission has a rewrite rule,
		// we prepare a SubjectFilterFunction to handle it accordingly.
		if child.GetRewrite() != nil {
			fn = engine.subjectFilterRewrite(ctx, request, child.GetRewrite())
		} else {
			fn = engine.subjectFilterLeaf(request, child.GetLeaf())
		}
	case base.EntityDefinition_REFERENCE_ATTRIBUTE:
		fn = engine.subjectFilterDirectAttribute(request)
	case base.EntityDefinition_REFERENCE_RELATION:
		fn = engine.subjectFilterDirectRelation(request)
	default:
		fn = engine.subjectFilterDirectCall(request)
	}

	// If we could not prepare a SubjectFilterFunction, we return a function that always fails with an error indicating undefined child kind.
	if fn == nil {
		return subjectFilterFail(errors.New(base.ErrorCode_ERROR_CODE_UNDEFINED_CHILD_KIND.String()))
	}

	// Finally, we return a function that combines results from the prepared function.
	return func(ctx context.Context) ([]string, error) {
		return subjectFilterUnion(ctx, []SubjectFilterFunction{fn}, engine.concurrencyLimit)
	}
}

// subjectFilterRewrite is a method for the SubjectFilterEngine struct.
// It generates a SubjectFilterFunction based on the rewrite operation type present in the provided request.