/// <summary>
/// Serialize an instance of type <see cref="T"/> to a byte array in avro format. The serialized
/// data is preceeded by a "magic byte" (1 byte) and the id of the schema as registered
/// in Confluent's Schema Registry (4 bytes, network byte order). This call may block or throw
/// on first use for a particular topic during schema registration.
/// </summary>
/// <param name="topic">
/// The topic associated wih the data.
/// </param>
/// <param name="data">
/// The object to serialize.
/// </param>
/// <returns>
/// <paramref name="data" /> serialized as a byte array.
/// </returns>
public byte[] Serialize(string topic, T data)
{
if (!topicsRegistered.Contains(topic))
{
string subject = IsKey
? SchemaRegistryClient.ConstructKeySubjectName(topic)
: SchemaRegistryClient.ConstructValueSubjectName(topic);
// first usage: register/get schema to check compatibility
if (AutoRegisterSchema)
{
SchemaId = SchemaRegistryClient.RegisterSchemaAsync(subject, writerSchemaString).Result;
}
else
{
SchemaId = SchemaRegistryClient.GetSchemaIdAsync(subject, writerSchemaString).Result;
}
topicsRegistered.Add(topic);
}
using (var stream = new MemoryStream(InitialBufferSize))
using (var writer = new BinaryWriter(stream))
{
stream.WriteByte(Constants.MagicByte);
writer.Write(IPAddress.HostToNetworkOrder(SchemaId.Value));
avroWriter.Write(data, new BinaryEncoder(stream));
// TODO: maybe change the ISerializer interface so that this copy isn't necessary.
return(stream.ToArray());
}
}
private async Task <string> GetSchemaIdAsync(Schema schema, CancellationToken cancellationToken)
{
var schemaProperties = _options.AutoRegisterSchemas
? (await _client.RegisterSchemaAsync(_groupName, schema.Fullname, schema.ToString(), SerializationType.Avro, cancellationToken).ConfigureAwait(false)).Value
: await _client.GetSchemaPropertiesAsync(_groupName, schema.Fullname, schema.ToString(), SerializationType.Avro, cancellationToken).ConfigureAwait(false);
return(schemaProperties.Id);
}