/// <summary>
/// Builds a deserializer for the Confluent wire format.
/// </summary>
/// <param name="id">
/// A schema ID that all payloads must be serialized with. If a received schema ID does not
/// match this ID, <see cref="InvalidDataException" /> will be thrown.
/// </param>
/// <param name="schema">
/// The schema to build the Avro deserializer from.
/// </param>
protected virtual IDeserializer <T> Build <T>(int id, string schema)
{
var deserialize = DeserializerBuilder.BuildDelegate <T>(SchemaReader.Read(schema));
return(new DelegateDeserializer <T>(stream =>
{
var bytes = new byte[4];
if (stream.ReadByte() != 0x00 || stream.Read(bytes, 0, bytes.Length) != bytes.Length)
{
throw new InvalidDataException("Data does not conform to the Confluent wire format.");
}
if (BitConverter.IsLittleEndian)
{
Array.Reverse(bytes);
}
var received = BitConverter.ToInt32(bytes, 0);
if (received != id)
{
throw new InvalidDataException($"The received schema ({received}) does not match the specified schema ({id}).");
}
return deserialize(stream);
}));
}
/// <summary>
/// Deserialize a message. (See <see cref="IAsyncDeserializer{T}.DeserializeAsync(ReadOnlyMemory{byte}, bool, SerializationContext)" />.)
/// </summary>
public virtual async Task <T> DeserializeAsync(ReadOnlyMemory <byte> data, bool isNull, SerializationContext context)
{
using (var stream = new MemoryStream(data.ToArray(), false))
{
var bytes = new byte[4];
if (stream.ReadByte() != 0x00 || stream.Read(bytes, 0, bytes.Length) != bytes.Length)
{
throw new InvalidDataException("Data does not conform to the Confluent wire format.");
}
if (BitConverter.IsLittleEndian)
{
Array.Reverse(bytes);
}
var @delegate = await(_cache.GetOrAdd(BitConverter.ToInt32(bytes, 0), async id =>
{
var json = await RegistryClient.GetSchemaAsync(id).ConfigureAwait(false);
var schema = SchemaReader.Read(json);
return(DeserializerBuilder.BuildDelegate <T>(schema));
})).ConfigureAwait(false);
return(@delegate(stream));
}
}
/// <summary>
/// Builds a deserializer for the Confluent wire format.
/// </summary>
/// <param name="id">
/// A schema ID that all payloads must be serialized with. If a received schema ID does not
/// match this ID, <see cref="InvalidDataException" /> will be thrown.
/// </param>
/// <param name="json">
/// The schema to build the Avro deserializer from.
/// </param>
/// <param name="tombstoneBehavior">
/// The behavior of the deserializer on tombstone records.
/// </param>
protected virtual IDeserializer <T> Build <T>(
int id,
string json,
TombstoneBehavior tombstoneBehavior
)
{
var schema = SchemaReader.Read(json);
if (tombstoneBehavior != TombstoneBehavior.None)
{
if (default(T) != null)
{
throw new UnsupportedTypeException(typeof(T), $"{typeof(T)} cannot represent tombstone values.");
}
var hasNull = schema is NullSchema ||
(schema is UnionSchema union && union.Schemas.Any(s => s is NullSchema));
if (tombstoneBehavior == TombstoneBehavior.Strict && hasNull)
{
throw new UnsupportedSchemaException(schema, "Tombstone deserialization is not supported for schemas that can represent null values.");
}
}
var deserialize = DeserializerBuilder.BuildDelegate <T>(schema);
return(new DelegateDeserializer <T>((data, isNull, context) =>
{
if (isNull && tombstoneBehavior != TombstoneBehavior.None)
{
if (context.Component == MessageComponentType.Value || tombstoneBehavior != TombstoneBehavior.Strict)
{
return default;
}
}
using (var stream = new MemoryStream(data, false))
{
var bytes = new byte[4];
if (stream.ReadByte() != 0x00 || stream.Read(bytes, 0, bytes.Length) != bytes.Length)
{
throw new InvalidDataException("Data does not conform to the Confluent wire format.");
}
if (BitConverter.IsLittleEndian)
{
Array.Reverse(bytes);
}
var received = BitConverter.ToInt32(bytes, 0);
if (received != id)
{
throw new InvalidDataException($"The received schema ({received}) does not match the specified schema ({id}).");
}
return deserialize(stream);
}
}));
}
