/// <summary>
/// Adds a new scalar type to the global collection of recognized scalar values. These graph types are used as
/// singleton instances across all schema's and all querys.
/// </summary>
/// <param name="graphType">The scalar type to register.</param>
public void RegisterCustomScalar(IScalarGraphType graphType)
{
Validation.ThrowIfNull(graphType, nameof(graphType));
if (string.IsNullOrWhiteSpace(graphType.Name))
{
throw new GraphTypeDeclarationException(
"The scalar must supply a name that is not null or whitespace.");
}
if (!GraphValidation.IsValidGraphName(graphType.Name))
{
throw new GraphTypeDeclarationException(
$"The scalar must supply a name that that conforms to the standard rules for GraphQL. (Regex: {Constants.RegExPatterns.NameRegex})");
}
if (graphType.Kind != TypeKind.SCALAR)
{
throw new GraphTypeDeclarationException(
$"The scalar's type kind must be set to '{nameof(TypeKind.SCALAR)}'.");
}
if (graphType.ObjectType == null)
{
throw new GraphTypeDeclarationException(
$"The scalar must supply a value for '{nameof(graphType.ObjectType)}', is cannot be null.");
}
if (graphType.SourceResolver == null)
{
throw new GraphTypeDeclarationException(
$"The scalar must supply a value for '{nameof(graphType.SourceResolver)}' that can convert data from a " +
$"query into the primary object type of '{graphType.ObjectType.FriendlyName()}'.");
}
if (graphType.ValueType == ScalarValueType.Unknown)
{
throw new GraphTypeDeclarationException(
$"The scalar must supply a value for '{nameof(graphType.ValueType)}'. This lets the validation engine " +
"know what data types submitted on a user query could be parsed into a value for this scale.");
}
if (graphType.OtherKnownTypes == null)
{
throw new GraphTypeDeclarationException(
$"Custom scalars must supply a value for '{nameof(graphType.OtherKnownTypes)}', it cannot be null. " +
"Use an empty list if there are no other known types.");
}
var isAScalarAlready = this.IsScalar(graphType.Name);
if (isAScalarAlready)
{
throw new GraphTypeDeclarationException(
$"A scalar named '{graphType.Name}' already exists in this graphql instance.");
}
isAScalarAlready = this.IsScalar(graphType.ObjectType);
if (isAScalarAlready)
{
var scalar = this.RetrieveScalar(graphType.ObjectType);
throw new GraphTypeDeclarationException(
$"The scalar's primary object type of '{graphType.ObjectType.FriendlyName()}' is " +
$"already reserved by the scalar '{scalar.Name}'. Scalar object types must be unique.");
}
foreach (var type in graphType.OtherKnownTypes)
{
isAScalarAlready = this.IsScalar(type);
if (isAScalarAlready)
{
var scalar = this.RetrieveScalar(type);
throw new GraphTypeDeclarationException(
$"The scalar's other known type of '{type.FriendlyName()}' is " +
$"already reserved by the scalar '{scalar.Name}'. Scalar object types must be unique.");
}
}
this.AddScalar(graphType);
}