public static IServiceCollection RegisterExtensibleTypes(
this IServiceCollection serviceCollection,
TypeDescriptorPolicy defaultTypeDescriptorPolicy,
IDictionary <Type, TypeDescriptorPolicy> typeDescriptorPolicyOverrides,
Assembly[] assemblies)
{
serviceCollection.Configure <JsonSerializerOptions>(options =>
{
var rootTypes = assemblies.SelectMany(a => a.GetTypes()
.Where(t =>
{
if (!typeof(IExtensible).IsAssignableFrom(t))
{
return(false);
}
var extensionDataProperty = t.GetProperty(nameof(IExtensible.ExtensionData), typeof(ExtensionData));
return(extensionDataProperty != null && extensionDataProperty.DeclaringType == t);
}))
.Distinct();
var typeHierarchyAssemblyMapping = rootTypes.Select(t => new { Type = t, Assemblies = assemblies.Where(a => a.GetTypes().Any(t.IsAssignableFrom)).Distinct() })
.ToDictionary(o => o.Type, o => o.Assemblies);
var typeMappings = new List <ITypeMappings>();
foreach (var(type, relatedAssemblies) in typeHierarchyAssemblyMapping)
{
if (!typeDescriptorPolicyOverrides.TryGetValue(type, out var typeDescriptorPolicy))
{
typeDescriptorPolicy = defaultTypeDescriptorPolicy;
}
typeMappings.Add(SerializationHelpers.CreateConstructor <SerializationHelpers.DefaultTypeMappingsConstructorDelegate>(typeof(DefaultTypeMappings <>).MakeGenericType(type))(relatedAssemblies, typeDescriptorPolicy));
}
options.Converters.Add(new ExtensibleJsonConverterFactory(typeMappings, defaultTypeDescriptorPolicy));
});
return(serviceCollection);
}
/// <inheritdoc />
public override JsonConverter CreateConverter(Type typeToConvert, JsonSerializerOptions options)
{
var ctor = GetConstructor(_converterGenericType.MakeGenericType(typeToConvert));
var rootType = typeToConvert.GetProperty(nameof(IExtensible.ExtensionData), typeof(ExtensionData))?.DeclaringType;
if (rootType == null)
{
throw new ArgumentException($"Cannot create an extensible JSON converter for type {typeToConvert} because it does not implement the {nameof(IExtensible)} interface.");
}
if (!_allTypeMappings.TryGetValue(rootType, out var typeMappings))
{
// Type mapping not configured yet for one reason or another.
// Configure type mappings by scanning assemblies where there are types that are assignable to the root type.
var assemblies = AppDomain.CurrentDomain.GetAssemblies().Where(a => a.GetTypes().Any(rootType.IsAssignableFrom));
typeMappings = SerializationHelpers.CreateConstructor <SerializationHelpers.DefaultTypeMappingsConstructorDelegate>(typeof(DefaultTypeMappings <>).MakeGenericType(rootType))(assemblies, _defaultTypeDescriptor);
_allTypeMappings[rootType] = typeMappings;
}
return(ctor(typeMappings));
}