graphql.validation.rules.SubscriptionUniqueRootField Maven / Gradle / Ivy
package graphql.validation.rules;
import graphql.Internal;
import graphql.execution.CoercedVariables;
import graphql.execution.FieldCollector;
import graphql.execution.FieldCollectorParameters;
import graphql.execution.MergedField;
import graphql.execution.MergedSelectionSet;
import graphql.language.NodeUtil;
import graphql.language.OperationDefinition;
import graphql.language.Selection;
import graphql.schema.GraphQLObjectType;
import graphql.validation.AbstractRule;
import graphql.validation.ValidationContext;
import graphql.validation.ValidationErrorCollector;
import java.util.List;
import static graphql.language.OperationDefinition.Operation.SUBSCRIPTION;
import static graphql.validation.ValidationErrorType.SubscriptionIntrospectionRootField;
import static graphql.validation.ValidationErrorType.SubscriptionMultipleRootFields;
/**
* A subscription operation must only have one root field
* A subscription operation's single root field must not be an introspection field
* https://spec.graphql.org/draft/#sec-Single-root-field
*/
@Internal
public class SubscriptionUniqueRootField extends AbstractRule {
private final FieldCollector fieldCollector = new FieldCollector();
public SubscriptionUniqueRootField(ValidationContext validationContext, ValidationErrorCollector validationErrorCollector) {
super(validationContext, validationErrorCollector);
}
@Override
public void checkOperationDefinition(OperationDefinition operationDef) {
if (operationDef.getOperation() == SUBSCRIPTION) {
GraphQLObjectType subscriptionType = getValidationContext().getSchema().getSubscriptionType();
FieldCollectorParameters collectorParameters = FieldCollectorParameters.newParameters()
.schema(getValidationContext().getSchema())
.fragments(NodeUtil.getFragmentsByName(getValidationContext().getDocument()))
.variables(CoercedVariables.emptyVariables().toMap())
.objectType(subscriptionType)
.graphQLContext(getValidationContext().getGraphQLContext())
.build();
MergedSelectionSet fields = fieldCollector.collectFields(collectorParameters, operationDef.getSelectionSet());
List subscriptionSelections = operationDef.getSelectionSet().getSelections();
if (fields.size() > 1) {
String message = i18n(SubscriptionMultipleRootFields, "SubscriptionUniqueRootField.multipleRootFields", operationDef.getName());
addError(SubscriptionMultipleRootFields, operationDef.getSourceLocation(), message);
} else { // Only one item in selection set, size == 1
MergedField mergedField = fields.getSubFieldsList().get(0);
if (isIntrospectionField(mergedField)) {
String message = i18n(SubscriptionIntrospectionRootField, "SubscriptionIntrospectionRootField.introspectionRootField", operationDef.getName(), mergedField.getName());
addError(SubscriptionIntrospectionRootField, mergedField.getSingleField().getSourceLocation(), message);
}
}
}
}
private boolean isIntrospectionField(MergedField field) {
return field.getName().startsWith("__");
}
}
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