private void OnTwinChangesReceived()

in iothub/device/src/Transport/AmqpIot/AmqpIotReceivingLink.cs [250:323]
62 lines of code
15 McCabe index (conditional complexity)

        private void OnTwinChangesReceived(AmqpMessage amqpMessage)
        {
            if (Logging.IsEnabled)
                Logging.Enter(this, amqpMessage, nameof(OnTwinChangesReceived));

            try
            {
                _receivingAmqpLink.DisposeDelivery(amqpMessage, true, AmqpIotConstants.AcceptedOutcome);
                string correlationId = amqpMessage.Properties?.CorrelationId?.ToString();
                int status = GetStatus(amqpMessage);

                Twin twin = null;
                TwinCollection twinProperties = null;

                if (status >= 400)
                {
                    // Handle failures
                    if (correlationId.StartsWith(AmqpTwinMessageType.Get.ToString(), StringComparison.OrdinalIgnoreCase)
                        || correlationId.StartsWith(AmqpTwinMessageType.Patch.ToString(), StringComparison.OrdinalIgnoreCase))
                    {
                        string error = null;
                        using var reader = new StreamReader(amqpMessage.BodyStream, System.Text.Encoding.UTF8);
                        error = reader.ReadToEnd();

                        // Retry for Http status code request timeout, Too many requests and server errors
                        var exception = new IotHubException(error, status >= 500 || status == 429 || status == 408);
                        _onTwinMessageReceived.Invoke(null, correlationId, null, exception);
                    }
                }
                else
                {
                    if (correlationId == null)
                    {
                        // Here we are getting desired property update notifications and want to handle it first
                        using var reader = new StreamReader(amqpMessage.BodyStream, System.Text.Encoding.UTF8);
                        string patch = reader.ReadToEnd();
                        twinProperties = JsonConvert.DeserializeObject<TwinCollection>(patch, JsonSerializerSettingsInitializer.GetJsonSerializerSettings());
                    }
                    else if (correlationId.StartsWith(AmqpTwinMessageType.Get.ToString(), StringComparison.OrdinalIgnoreCase))
                    {
                        // This a response of a GET TWIN so return (set) the full twin
                        using var reader = new StreamReader(amqpMessage.BodyStream, System.Text.Encoding.UTF8);
                        string body = reader.ReadToEnd();
                        TwinProperties properties = JsonConvert.DeserializeObject<TwinProperties>(body, JsonSerializerSettingsInitializer.GetJsonSerializerSettings());
                        twin = new Twin(properties);
                    }
                    else if (correlationId.StartsWith(AmqpTwinMessageType.Patch.ToString(), StringComparison.OrdinalIgnoreCase))
                    {
                        // This can be used to coorelate success response with updating reported properties
                        // However currently we do not have it as request response style implementation
                        if (Logging.IsEnabled)
                            Logging.Info("Updated twin reported properties successfully", nameof(OnTwinChangesReceived));
                    }
                    else if (correlationId.StartsWith(AmqpTwinMessageType.Put.ToString(), StringComparison.OrdinalIgnoreCase))
                    {
                        // This is an acknowledgement received from service for subscribing to desired property updates
                        if (Logging.IsEnabled)
                            Logging.Info("Subscribed for twin successfully", nameof(OnTwinChangesReceived));
                    }
                    else
                    {
                        // This shouldn't happen
                        if (Logging.IsEnabled)
                            Logging.Info("Received a correlation Id for Twin operation that does not match Get, Patch or Put request", nameof(OnTwinChangesReceived));
                    }
                    _onTwinMessageReceived.Invoke(twin, correlationId, twinProperties, null);
                }
            }
            finally
            {
                if (Logging.IsEnabled)
                    Logging.Exit(this, amqpMessage, nameof(OnTwinChangesReceived));
            }
        }