protected override bool VisitSelections(IOutputType outputType, SelectionSetNode selectionSet)
{
(outputType, selectionSet) = UnwrapOffsetBasedPaging(outputType, selectionSet);
if (outputType.NamedType() is ObjectType type)
{
foreach (IFieldSelection selection in CollectExtendedFields(type, selectionSet))
{
if (EnterSelection(selection))
{
LeaveSelection(selection);
}
}
}
else
{
throw new QueryException(
ErrorBuilder.New()
.SetMessage(
string.Format(
CultureInfo.InvariantCulture,
"UseSelection is in a invalid state. Type {0} is illegal!",
outputType.NamedType().Name))
.Build());
}
return(true);
}
public static IObjectFieldDescriptor UsePaging <TSchemaType>(
this IObjectFieldDescriptor descriptor)
where TSchemaType : IOutputType, new()
{
FieldMiddleware placeholder =
next => context => Task.CompletedTask;
Type middlewareDefinition = typeof(QueryableConnectionMiddleware <>);
descriptor
.AddPagingArguments()
.Type(ConnectionType <TSchemaType> .CreateWithTotalCount())
.Use(placeholder)
.Extend()
.OnBeforeCompletion((context, defintion) =>
{
var reference = new ClrTypeReference(
typeof(TSchemaType),
TypeContext.Output);
IOutputType type = context.GetType <IOutputType>(reference);
if (type.NamedType() is IHasClrType hasClrType)
{
Type middlewareType = middlewareDefinition
.MakeGenericType(hasClrType.ClrType);
FieldMiddleware middleware =
FieldClassMiddlewareFactory.Create(middlewareType);
int index =
defintion.MiddlewareComponents.IndexOf(placeholder);
defintion.MiddlewareComponents[index] = middleware;
}
})
.DependsOn <TSchemaType>();
return(descriptor);
}
public static IObjectFieldDescriptor UsePaging <TSchemaType>(
this IObjectFieldDescriptor descriptor)
where TSchemaType : class, IOutputType
{
FieldMiddleware placeholder = next => context => default(ValueTask);
Type middlewareDefinition = typeof(QueryableConnectionMiddleware <>);
descriptor
.AddPagingArguments()
.Type <ConnectionWithCountType <TSchemaType> >()
.Use(placeholder)
.Extend()
.OnBeforeCompletion((context, defintion) =>
{
ITypeReference reference =
context.DescriptorContext.TypeInspector.GetTypeRef(typeof(TSchemaType));
IOutputType type = context.GetType <IOutputType>(reference);
if (type.NamedType() is IHasRuntimeType hasClrType)
{
Type middlewareType = middlewareDefinition.MakeGenericType(
hasClrType.RuntimeType);
FieldMiddleware middleware = FieldClassMiddlewareFactory.Create(
middlewareType);
int index = defintion.MiddlewareComponents.IndexOf(placeholder);
defintion.MiddlewareComponents[index] = middleware;
}
})
.DependsOn <TSchemaType>();
return(descriptor);
}
protected virtual bool VisitSelections(
IOutputType outputType,
SelectionSetNode?selectionSet)
{
(outputType, selectionSet) = UnwrapPaging(outputType, selectionSet);
if (outputType.NamedType() is ObjectType type &&
selectionSet is { })
protected virtual ISelectionVisitorAction VisitChildren(
IOutputField field,
TContext context)
{
IOutputType type = field.Type;
SelectionSetNode?selectionSet =
context.SelectionSetNodes.Peek();
INamedType namedType = type.NamedType();
if (namedType.IsAbstractType())
{
IReadOnlyList <ObjectType> possibleTypes =
context.Context.Schema.GetPossibleTypes(field.Type.NamedType());
foreach (var possibleType in possibleTypes)
{
ISelectionVisitorAction result =
VisitObjectType(field, possibleType, selectionSet, context);
if (result != Continue)
{
return(result);
}
}
}
else if (namedType is ObjectType a)
{
return(VisitObjectType(field, a, selectionSet, context));
}
return(DefaultAction);
}
private Field GetField(
MatchSelectionsContext context,
FieldNode node,
IOutputType type)
{
if (GetDirective(node, "_field") is DirectiveNode directive &&
directive.Arguments.Count == 2 &&
directive.Arguments.FirstOrDefault(a => a.Name.Value.Equals("type")) is { } t&&
directive.Arguments.FirstOrDefault(a => a.Name.Value.Equals("name")) is { } n)
{
return(new Field(t.Name.Value, n.Name.Value));
}
return(new Field(type.NamedType().Name, node.Name.Value));
}
private bool TryUnwrapOffsetBasedPaging(
IOutputType outputType,
SelectionSetNode selectionSet,
out (IOutputType, SelectionSetNode) result)
{
result = (null, null);
if (outputType.NamedType() is ObjectType type)
{
foreach (IFieldSelection selection in Context.CollectFields(type, selectionSet))
{
IFieldSelection currentSelection = GetOffsetBasedPagingFieldOrDefault(selection);
if (currentSelection != null)
{
result = MergeSelection(result.Item2, currentSelection);
}
}
}
return(result.Item2 != null);
}
