Passing JSON to WebApi in MVC4(RC) and .NET Framework 4.5(RC)

Question

4.67/5 (3 votes)

See more:

Hey guys,

I'm trying to pass a model from a class library to a RESTful web-api. Problem is, that I receive an exception : No MediaTypeFormatter is available to read an object of type 'EnvironmentHeartbeatModel' from content with media type 'undefined'.

Now using fiddler, if I change the content-type of the header to application/json, everything works fine. However, in my client code :

C#

public class RestApiInvocations<T>
{
    public HttpResponseMessage Post(string url, T model)
    {
        HttpResponseMessage result = null;
        HttpClient client = new HttpClient();
        try
        {
             result = client.PostAsJsonAsync(url, model).Result;
        }
        catch (Exception ex)
        {
            System.Diagnostics.Debug.WriteLine(ex);
        }
        return result;

    }
}

The HttpClient object doesn't allow me to add a Content-Type header. I CAN add an Accept header, so I tried to add an accept header with application/json, but without result.

In my API controller, I added the [FromUri] and [FromBody] attributes on the incomming parameters.

Anyone?

Thanks!

Posted 19-Jun-12 4:24am

Eduard Keilholz

Add a Solution

3 solutions

Solution 3

Ah thanks for the answer. Sorry if i lead you down the wrong path.

Posted 20-Jun-12 13:19pm

AlexPZA

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

AlexPZA · Accepted Answer · 2012-06-19T15:33:00

Should you not be serializing the model and creating an httpconent element out of that ?

Then set the ContentType on that element

C#

  JsonSerializerSettings _settings = new JsonSerializerSettings();
  JsonSerializer ser = JsonSerializer.Create(_settings);
  JObject j = JObject.FromObject(model, ser);
  HttpContent content = new StringContent(j.ToString());
  content.Headers.ContentType = new  System.Net.Http.Headers.MediaTypeHeaderValue("application/json");
try
  {
      result = client.PostAsJsonAsync(url, model).Result;
  }

I generally just use the client.PostAsync but it should work.

Could be wrong though !

Eduard Keilholz · Accepted Answer · 2012-06-20T09:53:00

Solution 2

The trick is to add a BaseUrl to the client, and insert the path in the PostAsJsonAsync, in stead of just passing the entire url to the PostAsJsonAsync. Thanks for your reply anyway!

Posted 20-Jun-12 9:53am