NTDLS.MemoryQueue

?? Be sure to check out the NuGet package: https://www.nuget.org/packages/NTDLS.MemoryQueue

In memory non-persistent message queue with notifications/messages, query/reply support and several message broadcast schemes. Intended for inter-process-communication, queuing, load-balancing and buffering over TCP/IP.

Running the server:

Running the server can literally be done with two lines of code and can be run in the same process as the client. The server does not have to be dedicated either, it can be one of the process that is involved in inner-process-communication.

internal class Program
{
    static var _server = new MqServer(); //Literal line #1.

    static void Main()
    {
        _server.Start(45784); //Literal line #2.

        Console.WriteLine("Press [enter] to shutdown.");
        Console.ReadLine();

        server.Shutdown();
    }
}

Enqueuing a message which does not expect a reply.

Enqueuing a one-way message that is broadcast to all connected peers that have subscribed to the queue.

internal class Program
{
    internal class MyMessage : IMqMessage
    {
        public string Text { get; set; }

        public MyMessage(string text)
        {
            Text = text;
        }
    }

    static void Main()
    {
        //Start a client and connect to the server.
        var client = new MqClient();

        //Enqueue a one-way message to be distributed to all subscribers.
        client.EnqueueMessage("MyFirstQueue", new MyMessage("This is a message"));

        Console.WriteLine("Press [enter] to shutdown.");
        Console.ReadLine();

        client.Disconnect();
    }
}

Receiving a notification message:

Receiving a notification is easy. If you are subscribed to the queue, you will receive the message. Further messages will be held until the event method returns.

internal class Program
{
    internal class MyMessage : IMqMessage
    {
        public string Text { get; set; }

        public MyMessage(string text)
        {
            Text = text;
        }
    }

    static void Main()
    {
        var client = new MqClient();

        //Connect to the queue server.
        client.Connect("localhost", 45784);

        //Wire up the OnMessageReceived event.
        client.OnMessageReceived += Client_OnMessageReceived;

        //Create a queue, its ok its it already exists.
        client.CreateQueue(new MqQueueConfiguration("MyFirstQueue"));

        //Subscribe to the queue.
        client.Subscribe("MyFirstQueue");

        Console.WriteLine("Press [enter] to shutdown.");
        Console.ReadLine();

        client.Disconnect();
    }

    private static void Client_OnMessageReceived(MqClient client, IMqMessage message)
    {
        //We received a message. There are numerous ways to handle these, but here
        //  we are going to pattern matching to determine what message was received.
        if (message is MyMessage myMessage)
        {
            Console.WriteLine($"Client received message from server: {myMessage.Text}");
        }
    }
}

Enqueuing a query, a message type that does expect a reply:

You can also enqueue a query. The query will be received by all subscribed clients and any one of them can respond. The async task will completed once a client receives and responds to the query. Note that only one clients reply will be received. All other replies are discarded.

internal class Program
{
    internal class MyQuery : IMqQuery
    {
        public string Message { get; set; }

        public MyQuery(string message)
        {
            Message = message;
        }
    }

    internal class MyQueryReply : IMqQueryReply
    {
        public string Message { get; set; }

        public MyQueryReply(string message)
        {
            Message = message;
        }
    }

    static void Main()
    {
        var client = new MqClient();

        //Connect to the queue server.
        client.Connect("localhost", 45784);

        //Create a queue, its ok its it already exists.
        client.CreateQueue(new MqQueueConfiguration("MyFirstQueue"));

        //Subscribing to the queue is commented out to demonstrate that a client does not
        //  have to be subscribed to a queue to receive a reply from a query sent to that queue.
        //client.Subscribe("MyFirstQueue");

        //Enqueue a query that is to be distributed to all subscribers. The first one to reply wins.
        client.EnqueueQuery<MyQueryReply>("MyFirstQueue", new MyQuery("Ping!")).ContinueWith((o) =>
        {
            //We received a reply to the query. There are numerous ways to handle these,
            //  but here we are going to pattern matching to determine what message was received.
            if (o.IsCompletedSuccessfully && o.Result != null)
            {
                //We received a reply!
                Console.WriteLine($"Query Reply: {o.Result.Message}");
            }
        });

        Console.WriteLine("Press [enter] to shutdown.");
        Console.ReadLine();

        client.Disconnect();
    }
}

Receiving a query and replying to it:

Receiving a query and responding to it is easy. The server handles all the routing.

internal class Program
{
    static void Main()
    {
        var client = new MqClient();

        //Connect to the queue server.
        client.Connect("localhost", 45784);

        //Wire up the OnQueryReceived event.
        client.OnQueryReceived += Client_OnQueryReceived;

        //Create a queue, its ok its it already exists.
        client.CreateQueue(new MqQueueConfiguration("MyFirstQueue"));

        //Subscribe to the queue.
        client.Subscribe("MyFirstQueue");

        Console.WriteLine("Press [enter] to shutdown.");
        Console.ReadLine();

        client.Disconnect();
    }

    private static IMqQueryReply Client_OnQueryReceived(MqClient client, IMqQuery query)
    {
        //We received a query. There are numerous ways to handle these, but here we are
        //  going to pattern matching to determine what query was received.
        if (query is MyQuery myQuery)
        {
            //The query of type MyQuery expects a reply of type MyQueryReply.
            return new MyQueryReply("This is my reply");
        }

        throw new Exception("The query was unhandled.");
    }
}

License

MIT