Confused about running async methods in the background

Question

Say I have the following methods, in my ASP.NET 5 Web API:

//(in a different class)
public static async Task SendStatus(string message)
{
    await SendStatusMessage(message); //sends a status message to the client
}

[HttpGet("api/dowork")]
public async Task<IActionResult> DoWork()
{
    await SendStatusToClient("starting to do work!");

    //when it reaches this point, it should run the code in the background

    await DoTheActualWork();
    await SendStatusToClient("finished work!");


    //I want the control back after it starts running the above code in the background, to send a 200 status code 
    return Ok();
}

This is how it should run:

1. It sends a status message, stating that it has started doing the work.
2. It does the work, and after the work is done, sends a status message. All of this should be done in the background.
3. Return a 200 (OK) status code to the user who requested the work. The actual work takes a significant amount of time and should still be running in the background.

How would I achieve this?

Answer 1

There are two answers helpful to you.

1. The first one, how to do it: Webapi2 - Return from controller action after one task completes, but continue with further Async processing
2. The second one, why not do it: How to answer a request but continue processing code in WebApi

So what to do now. I would suggest the following steps:

1. Create a queue. Either a database table an azure service bus queue, a rabbitmq queue or even a simple file or just a static memory structure. (Production loads require some persistence though)
2. Create a long running task to process the queued items. Web api supports background tasks, but you could create a service a job on the cloud or a windows service or any other application or service that works.