Ais.Net.Models.Json.Nats

A NATS.Net serializer for the Ais.Net.Models AIS message types, built on the low-allocation, polymorphic Ais.Net.Models.Json serializer.

Publish decoded AIS messages over NATS as UTF-8 JSON and reconstruct the concrete .NET type on the receiving end. Sponsored by endjin.

Features

• Implements NATS.Net's INatsSerializer<AisMessageBase> (serialize + deserialize) over Ais.Net.Models.Json.
• Polymorphic: publish and subscribe as AisMessageBase; a $type discriminator reconstructs the correct concrete message (AisMessageType1Through3, AisMessageType5, …) on receipt.
• Low allocation: serialization writes straight to the NATS IBufferWriter<byte> (no intermediate array); deserialization reads the payload span directly for the common single-segment case.
• An optional INatsSerializerRegistry so an AIS-only connection can use the serializer by default.

Usage

Per publish / subscribe

using Ais.Net.Models;
using Ais.Net.Models.Json.Nats;
using NATS.Client.Core;

await using var connection = new NatsConnection();

// Publish — any AisMessageBase is written as polymorphic UTF-8 JSON.
await connection.PublishAsync("ais.stream", message, serializer: AisMessageNatsSerializer.Default);

// Subscribe — the concrete type is reconstructed from the $type discriminator.
await foreach (var msg in connection.SubscribeAsync<AisMessageBase>(
    "ais.stream", serializer: AisMessageNatsSerializer.Default))
{
    if (msg.Data is AisMessageType18 positionReport)
    {
        // ...
    }
}

Examples use NatsConnection from NATS.Client.Core (this package's dependency). The higher-level NatsClient from the NATS.Net meta-package exposes the same PublishAsync/SubscribeAsync if you prefer it.

Default serializer for a connection

For a connection that carries only AIS messages, register the serializer once so callers need not pass it on every operation:

using Ais.Net.Models.Json.Nats;
using NATS.Client.Core;

var opts = new NatsOpts { SerializerRegistry = AisMessageNatsSerializerRegistry.Default };
await using var connection = new NatsConnection(opts);

The registry handles AisMessageBase only; requesting a serializer for any other type throws NotSupportedException. To mix AIS and non-AIS payloads on one connection, pass a per-call serializer instead.

Building

Requires the .NET 10 SDK. Depends on the Ais.Net.Models.Json (1.0.0 or later) and NATS.Client.Core packages.

dotnet build Solutions/Ais.Net.Models.Json.Nats.slnx -c Release

Licenses

Licensed under the Apache 2.0 License.