async at console app in C#? [duplicate]

Question

In most project types, your async "up" and "down" will end at an async void event handler or returning a Task to your framework.

However, Console apps do not support this.

You can either just do a Wait on the returned task:

static void Main()
{
  MainAsync().Wait();
  // or, if you want to avoid exceptions being wrapped into AggregateException:
  //  MainAsync().GetAwaiter().GetResult();
}

static async Task MainAsync()
{
  ...
}

or you can use your own context like the one I wrote:

static void Main()
{
  AsyncContext.Run(() => MainAsync());
}

static async Task MainAsync()
{
  ...
}

More information for async Console apps is on my blog.

Here is the simplest way to do this

static void Main(string[] args)
{
    Task t = MainAsync(args);
    t.Wait();
}

static async Task MainAsync(string[] args)
{
    await ...
}

As a quick and very scoped solution:

Task.Result

Both Task.Result and Task.Wait won't allow to improving scalability when used with I/O, as they will cause the calling thread to stay blocked waiting for the I/O to end.

When you call .Result on an incomplete Task, the thread executing the method has to sit and wait for the task to complete, which blocks the thread from doing any other useful work in the meantime. This negates the benefit of the asynchronous nature of the task.

notasync

My solution. The JSONServer is a class I wrote for running an HttpListener server in a console window.

class Program
{
    public static JSONServer srv = null;

    static void Main(string[] args)
    {
        Console.WriteLine("NLPS Core Server");

        srv = new JSONServer(100);
        srv.Start();

        InputLoopProcessor();

        while(srv.IsRunning)
        {
            Thread.Sleep(250);
        }

    }

    private static async Task InputLoopProcessor()
    {
        string line = "";

        Console.WriteLine("Core NLPS Server: Started on port 8080. " + DateTime.Now);

        while(line != "quit")
        {
            Console.Write(": ");
            line = Console.ReadLine().ToLower();
            Console.WriteLine(line);

            if(line == "?" || line == "help")
            {
                Console.WriteLine("Core NLPS Server Help");
                Console.WriteLine("    ? or help: Show this help.");
                Console.WriteLine("    quit: Stop the server.");
            }
        }
        srv.Stop();
        Console.WriteLine("Core Processor done at " + DateTime.Now);

    }
}