Web API Service - How to make the requests at the server to be executed concurrently

Question

I am using a WebApi rest service controller, hosted by IIS 7.5, as i understood from this post:

Are all the web requests executed in parallel and handled asynchrono

Answer 1

Do you try async Task ? Here is sample Controller:

public class SendJobController : ApiController
    {
        public async Task<ResponseEntity<SendJobResponse>> Post([FromBody] SendJobRequest request)
        {
            return await PostAsync(request);
        }

        private async Task<ResponseEntity<SendJobResponse>> PostAsync(SendJobRequest request)
        {
            Task<ResponseEntity<SendJobResponse>> t = new Task<ResponseEntity<SendJobResponse>>(() =>
            {
                ResponseEntity<SendJobResponse> _response = new ResponseEntity<SendJobResponse>();

                try
                {
                    //  
                    // some long process
                    // 
                    _response.responseStatus = "OK"; 
                    _response.responseMessage = "Success";
                    _response.responseObject = new SendJobResponse() { JobId = 1 };

                }
                catch (Exception ex)
                {
                    _response.responseStatus = "ERROR"; 
                    _response.responseMessage = ex.Message;
                }

                return _response;
            });

            t.Start();
            return await t;
        }
    }

Answer 2

Actually, disabling session state is the normal solution for web APIs. If you need it for some/all of your calls, you can call HttpContext.SetSessionStateBehavior (e.g., from Application_BeginRequest). Multiple read-only session state requests can run concurrently.