TTN V3 Application API Basic Paging Client

The next step was to enumerate The Things Network(TTN) Applications and their attributes. I’m planning on using attributes to manage which applications (and in future EndDevices) are enabled in my Advanced Message Queuing Protocol(AMQP) client.

In the code I have left the different paging implementations which I trialled but abandoned.

using (HttpClient httpClient = new HttpClient())
{
	ApplicationRegistryClient applicationRegistryClient = new ApplicationRegistryClient(baseUrl, httpClient)
	{
		ApiKey = apiKey
	};

	try
	{
		int page = 1;
		string[] fieldMaskPathsApplication = { "attributes" };

		V3Applications applications = await applicationRegistryClient.ListAsync(collaborator, field_mask_paths: fieldMaskPathsApplication, limit:pageSize, page: page);
		while ((applications != null) && (applications.Applications != null))
		{ 
			Console.WriteLine($"Applications:{applications.Applications.Count} Page:{page} Page size:{pageSize}");
			foreach (V3Application application in applications.Applications)
			{
				Console.WriteLine($"Application ID:{application.Ids.Application_id}"); 
				if (application.Attributes != null)
				{
					Console.WriteLine("  Application attributes");

					foreach (KeyValuePair<string, string> attribute in application.Attributes)
					{
						Console.WriteLine($"   Key: {attribute.Key} Value: {attribute.Value}");
					}
				}
				Console.WriteLine();
			}
			page += 1;
			applications = await applicationRegistryClient.ListAsync(collaborator, field_mask_paths: fieldMaskPathsApplication, limit: pageSize, page: page);
		}
	}   
}

For each LoraWAN client I have to have an open connection to the Azure IoT hub to get Cloud to Device (C2D) messages so I’m looking at using connection pooling to reduce the overall number of connections.

I think the Azure ClientDevice library supports up to 995 devices per connection and has quiet a lot of additional functionality.

/// <summary>
/// contains Amqp Connection Pool settings for DeviceClient
/// </summary>
public sealed class AmqpConnectionPoolSettings
{
   private static readonly TimeSpan s_defaultConnectionIdleTimeout = TimeSpan.FromMinutes(2);
    private uint _maxPoolSize;
    internal const uint MaxDevicesPerConnection = 995; // IotHub allows upto 999 tokens per connection. Setting the threshold just below that.

    /// <summary>
    /// The default size of the pool
    /// </summary>
    /// <remarks>
    /// Allows up to 100,000 devices
    /// </remarks>
    private const uint DefaultPoolSize = 100;

    /// <summary>
    /// The maximum value that can be used for the MaxPoolSize property
    /// </summary>
     public const uint AbsoluteMaxPoolSize = ushort.MaxValue;

    /// <summary>
    /// Creates an instance of AmqpConnecitonPoolSettings with default properties
    /// </summary>
    public AmqpConnectionPoolSettings()
    {
       _maxPoolSize = DefaultPoolSize;
       Pooling = false;
    }

Whereas I think AMQPNetLite may support more, but will require me to implement more of the Azure IoT client interface

/// <summary>
/// The default maximum frame size used by the library.
/// </summary>
public const uint DefaultMaxFrameSize = 64 * 1024;
internal const ushort DefaultMaxConcurrentChannels = 8 * 1024;
internal const uint DefaultMaxLinkHandles = 256 * 1024;
internal const uint DefaultHeartBeatInterval = 90000;
internal const uint MinimumHeartBeatIntervalMs = 5 * 1000;

I have got todo some more research to see which library is easier/requires more code/complex/scales better.

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