binding.md

Binding

Binding reads values from MQTT route values, payload, client information, user properties, session items, and routing contexts. Binding failures are recorded in MqttModelStateDictionary.

Sources

[MqttRoute("devices/{deviceId}/state")]
public MqttResult State(
    [FromMqttRoute] Guid deviceId,
    [FromMqttPayload] StatePayload payload,
    [FromMqttClient] string clientId,
    [FromMqttUserProperty("trace-id")] string traceId,
    [FromMqttSession("tenant")] string tenant,
    MqttRequestContext request,
    MqttActionContext action)
{
    return Acknowledge();
}

Supported route conversions include string, Guid, numeric types, bool, enum, nullable values, and optional route segments.

Payloads

[FromMqttPayload] uses the formatter pipeline. Formatter selection checks the attribute declaration, MQTT v5 content type, route metadata, and default routing options.

public MqttResult Command(
    [FromMqttPayload("application/json", FormatterName = "json")] CommandPayload payload)
{
    return Suppress();
}

Raw payload values can be bound as byte[], ReadOnlyMemory<byte>, or MqttApplicationMessage.