ASP.NET WebApi Post Method - 404 When Passing Parameters

Question

I cannot for the life of me figure this out. I have a web api controller with Get and Post methods. The Get method works fine with and without parameters, but the post breaks when I try to add a String parameter to it. Below is my code.

Route:

        config.Routes.MapHttpRoute(
            name: "DefaultApi",
            routeTemplate: "{controller}/{id}",
            defaults: new { id = UrlParameter.Optional }
        );

Controller:

public class AuditController : ApiController
{
    public String Post(String test)
    {
        return "Success : " + test;
    }

    public String Get(String test)
    {
        return "Success : " + test;
    }
}

Request:

    var request = WebRequest.Create("http://localhost:42652/Audit");
        request.Method = "POST";
        request.ContentType = "application/x-www-form-urlencoded";
        using (var writer = new StreamWriter(request.GetRequestStream()))
        {
            writer.Write("test=TEST");
        }
        WebResponse webResponse = request.GetResponse();

I've tried many variations on the request, I feel like there's something simple I'm missing. Thanks for your help.

Your route says it has a parameter named id, but in your method you pass a parameter named test. What shall it be? Also primitive type parameters are always tried to read from the Uri, so your post method won't work. I really suggest you to work through all the very nice ASP.Net Web API tutorials on the asp.net homepage! — JustAnotherUserYouMayKnow
– JustAnotherUserYouMayKnow, Commented Jun 11, 2013 at 15:44
Yes it is. Your Get-method represents the Route without the {id} parameter - because your id parameter is not present in the method. Your test-parameter is one of the optional query parameters, when you call Audit?test=value, but not on Audit/value. The answer you accepted sum this up good, but I still encourage you to really work through the tutorials! — JustAnotherUserYouMayKnow
– JustAnotherUserYouMayKnow, Commented Jun 12, 2013 at 6:48

Kiran · Accepted Answer · 2013-06-11 15:51:21Z

22

Since you are expecting parameter test to come from body of a request, you would need to decorate it with FromBody attribute. Example: ([FromBody]String test). This is not true for other complex types, for example: Employee class which is implicitly considered to be coming from Body.

Rearding GET request. It should be working only with test coming from query string /Audit?test=Mike

Following blog post has more details about parameter binding: http://blogs.msdn.com/b/jmstall/archive/2012/04/16/how-webapi-does-parameter-binding.aspx

Also, I see that you are using WebRequest. Have you considered using HttpClient from System.Net.Http instead?

answered Jun 11, 2013 at 15:51

Kiran

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3 Comments

Jonesopolis Over a year ago

I added the FromBody attribute, and it will reach the service now, but the 'test' variable inside the post method is null unfortunately. I will have a look at HttpClient as well.

Kiran Over a year ago

try sending just =TEST in your body.

Tod Over a year ago

For fuffuf fuffsake. WHY???? Thank you for this, it brought an end to an otherwise annoying morning. Mostly filled with totally unintuitive programming decisions.

adhocgeek · Accepted Answer · 2013-06-11 16:44:25Z

3

Change your AuditController to include the FromBody attribute :

public class AuditController : ApiController
{
    public String Post([FromBody]String test)
    {
        return "Success : " + test;
    }

    public String Get(String test)
    {
        return "Success : " + test;
    }
}

cf. http://msdn.microsoft.com/en-us/library/system.web.http.frombodyattribute(v=vs.108).aspx

edited Jun 11, 2013 at 16:44

answered Jun 11, 2013 at 15:48

adhocgeek

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