public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
var objectType = value.GetType();
try
{
_MigratedTypes.Value[objectType] = true;
var obj = JObject.FromObject(value, serializer);
obj[VersionMemberName.VersionPropertyName] = VersionMemberName.GetCurrentVersion(objectType);
obj.WriteTo(writer);
}
finally
{
_MigratedTypes.Value[objectType] = false;
}
}
/// <summary>
/// Try to migrate the serialized data to a newer version using migration methods from type unserializedDataType.
/// </summary>
/// <param name="serializedData"></param>
/// <param name="unserializedDataType"></param>
/// <param name="serializer"></param>
/// <returns></returns>
public Tuple <TSerializedData, bool> TryMigrate(TSerializedData serializedData, Type unserializedDataType, JsonSerializer serializer)
{
if (serializedData == null)
{
throw new ArgumentNullException(nameof(serializedData));
}
if (unserializedDataType == null)
{
throw new ArgumentNullException(nameof(unserializedDataType));
}
var migrationSettings = unserializedDataType.GetTypeInfo().GetCustomAttribute <MigratableAttribute>();
if (migrationSettings == null)
{
return(Tuple.Create(serializedData, false));
}
var version = _VersionExtractor.GetVersion(serializedData);
var allMigrationMethods = VersionMemberName
.GetMigrationMethods(unserializedDataType)
.ToList();
var maxSupportedVersion = allMigrationMethods.LastOrDefault()?.ToVersion ?? 0;
if (version > maxSupportedVersion)
{
throw new DataVersionTooHighException($"Trying to load data type '{unserializedDataType.FullName}' from json data " +
$"at version {version}." +
$" However current software only supports version {maxSupportedVersion}." +
" Please update your installation with a newwer version.");
}
var migrationMethods = allMigrationMethods
.SkipWhile(m => m.ToVersion <= version)
.ToList();
var migrated = migrationMethods.Count > 0;
try
{
serializedData = migrationMethods
.Select(m => unserializedDataType.GetTypeInfo().GetDeclaredMethod(m.Name))
.Aggregate(serializedData,
(data, method) => ExecuteMigration(method, data, serializer));
}
catch (Exception e)
{
var migrationMethodVerifier = new MigrationMethodVerifier(VersionMemberName.CanAssign);
var invalidMethod = migrationMethodVerifier.VerifyMigrationMethods(allMigrationMethods);
foreach (var method in invalidMethod)
{
method.ThrowIfInvalid(e);
}
// Exception doesn't come from invalid migration methods -> rethrow
throw;
}
_VersionExtractor.SetVersion(serializedData, maxSupportedVersion);
return(Tuple.Create(serializedData, migrated));
}