Asp Web Api async action - 404 error

Question

I've got some api controller with this action:

public class ProxyController : ApiController {
    public async Task<HttpResponseMessage> PostActionAsync(string confirmKey)
    {
         return await Task<HttpResponseMessage>.Factory.StartNew( () =>
               {
                  var result = GetSomeResult(confirmKey);
                  return Request.CreateResponse(HttpStatusCode.Created, result);
               });
    }
}

And here is my api routing confuguration:

routes.MapHttpRoute("DefaultApi", "api/{controller}/{action}/{id}", new { id = RouteParameter.Optional });

When I try to make any Post/Get Requests to this action, it's returns '404' error. How can I fix it? All other not-async actions in this controller works fine.

UPD. JS query:

$.ajax({
        url: Url + '/api/Proxy/PostActionAsync',
        type: 'POST',
        data: { confirmKey: that.confirmKey },                  
        dataType: 'json',                   
        xhrFields: {  withCredentials: true  },
        success: function (data) {
            ............
        },
        error: function (jqXHR, textStatus, errorThrown) {
             ............
        }                        
});

UPD. Resolved by adding [FromBody] to my parameters in action method just like in J. Steen's answer, now it's look's like

public class ProxyController : ApiController {
       public async Task<HttpResponseMessage> PostActionAsync([FromBody]string confirmKey)
        {
            var someModel = new SomeResultModel(User.Identity.Name);
            await Task.Factory.StartNew(() => someModel.PrepareModel(confirmKey));

            return Request.CreateResponse(HttpStatusCode.OK, someModel);
        }
    }

And it works!

Post your ActionResult Method and Controller name too. If possible your async calling Jquery too., :) — Rajeshkumar Kandhasamy
– Rajeshkumar Kandhasamy, Commented Apr 29, 2013 at 15:14

J. Steen · Accepted Answer · 2013-04-30 09:09:35Z

3

The routing configuration for Web API works a little differently than MVC.

Try

routes.MapHttpRoute("DefaultApi", "api/{controller}/{id}", new { id = RouteParameter.Optional });

Note the missing {action} as that is resolved by Web API at call-time, automagically, depending on the HTTP verb you use for your request.

Consider this article on Web API routing which lists (as an example):

HTTP Method  URI Path            Action           Parameter
GET          api/products        GetAllProducts   (none)
GET          api/products/4      GetProductById   4
DELETE       api/products/4      DeleteProduct    4

In your case, the async version of an action is also resolved automatically.

POST         api/products        PostActionAsync  (Post data)

Since we now know the controller name, requests would be like:

GET api/proxy
GET api/proxy/4
POST api/proxy (with post data)

Edit:

After additional research (brief, I admit) I have found the issue.

You need to add [FromBody] infront of your in-parameter.

public async Task<HttpResponseMessage> PostActionAsync([FromBody] string confirmKey)

This, combined with sending just the value (no wrapping json) works wonders. Set content type to "application/x-www-form-urlencoded" instead of json, and send your parameter as "=" + that.confirmKey.

Alternative:

If you don't want to fiddle around with content-types and prefixing =-signs, just send it as part of the querystring. Forget the [FromBody] and the rest. Call

/api/Proxy/PostActionAsync?confirmKey=' + that.confirmKey

Additional, exhaustive information in this blog.

edited Apr 30, 2013 at 9:09

answered Apr 29, 2013 at 15:28

J. Steen

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12 Comments

Igor Konopko Over a year ago

I've changed routing as at youre example, also my client ajax url changed to ServerUrl+ '/api/Proxy?action=PostActionAsync', now it return's 500 (Internal Server Error). Is it meen that I should use only one get/post/put action in one api controller?

J. Steen Over a year ago

The convention is to only use one POST per controller. Also, ?action=PostActionAsync probably won't work well either, I'm sorry to say. =/

J. Steen Over a year ago

I am wildly confused. If you want action-based routing, my answer is wrong. Your route-config needs to be as you originally stated it.

Igor Konopko Over a year ago

you mean like in top post?

J. Steen Over a year ago

I've been trying your code, creating a controller with a post async action, and your original routing configuration. For me, it works just as expected. Are you sure the Url parameter you paste infront of your api/Proxy/PostActionAsync has the correct value?

|

Vladimir · Accepted Answer · 2013-04-29 15:15:00Z

1

Is that change possible?

public async Task<HttpResponseMessage> PostActionAsync()
{
    var result = await GetSomeResult();
    return Request.CreateResponse(HttpStatusCode.Created, result);
}

answered Apr 29, 2013 at 15:15

Vladimir

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4 Comments

Igor Konopko Over a year ago

'CreateResponse()' returns 'HttpResponseMessage', which can't be converted to 'Task<HttpResponseMessage>'

Vladimir Over a year ago

async Task<string> WaitAsynchronouslyAsync() { await Task.Delay(10000); return "Finished"; } This is example from MSDN.

Vladimir Over a year ago

If your PrepareModel method return bool you can change:

var eventModel = new EventResultModel(...); var result = await eventModel.PrepareModel(confirmKey)); if (result) { return Request.CreateResponse(HttpStatusCode.OK, eventModel); } else { ...error response... }

Igor Konopko Over a year ago

but when I try to make Get request to this action, it's says that action allowed only for Post requests

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