c# - Post values are not set because of special characters in Web API

Question

I'm trying to make a post to my web api service. The point is that while sending a message like

{ message: "it is done" }

working fine. However when I use special characters like çıöpş in my message it is unable to convert my json so that the post object remains null. What can I do? It is either current culture issue or something else. I tried to send my post parameter as HtmlEncoded style with encoding HttpUtility class but it didn't work either.

public class Animal{

  public string Message {get;set;}
}

Web API method

public void DoSomething(Animal a){

}

Client

Animal a = new Animal();
a.Message = "öçşistltl";
string postDataString = JsonConvert.SerializeObject(a);        
string URL = "http://localhost/Values/DoSomething";
WebClient client = new WebClient();

client.UploadStringCompleted += client_UploadStringCompleted;
client.Headers["Content-Type"] = "application/json;charset=utf-8";
client.UploadStringAsync(new Uri(URL), "POST",postDataString);

Best regards,

Kemal

Answer 1

One possibility is to use the UploadDataAsync method which allows you to specify UTF-8 when encoding the data because the UploadStringAsync method that you are using basically uses Encoding.Default to encode the data when writing it to the socket. So if your system is configured to use some other encoding than UTF-8 you get into trouble because UploadStringAsync uses your system encoding whereas in your content type header you have specified charset=utf-8 which could be conflicting.

With the UploadDataAsync method you could be more explicit in your intents:

Animal a = new Animal();
a.Message = "öçşistltl";
string postDataString = JsonConvert.SerializeObject(a);        
string URL = "http://localhost/Values/DoSomething";
string postDataString = JsonConvert.SerializeObject(a);
using (WebClient client = new WebClient())
{
    client.UploadDataCompleted += client_UploadDataCompleted;
    client.Headers["Content-Type"] = "application/json; charset=utf-8";
    client.UploadDataAsync(new Uri(URI), "POST", Encoding.UTF8.GetBytes(postDataString));
}

---

Another possibility is to specify the encoding of the client and use UploadStringAsync:

Animal a = new Animal();
a.Message = "öçşistltl";
string postDataString = JsonConvert.SerializeObject(a);        
string URL = "http://localhost/Values/DoSomething";
string postDataString = JsonConvert.SerializeObject(a);
using (WebClient client = new WebClient())
{
    client.Encoding = Encoding.UTF8;
    client.UploadStringCompleted += client_UploadStringCompleted;
    client.Headers["Content-Type"] = "application/json; charset=utf-8";
    client.UploadStringAsync(new Uri(URI), "POST", postDataString);
}

---

Or if you install the Microsoft.AspNet.WebApi.Client NuGet package on the client you could directly use the new HttpClient class (which is the new kid on the block) to consume your WebAPI instead of WebClient:

Animal a = new Animal();
a.Message = "öçşistltl";
var URI = "http://localhost/Values/DoSomething";
using (var client = new HttpClient())
{
    client
        .PostAsync<Animal>(URI, a, new JsonMediaTypeFormatter())
        .ContinueWith(x => x.Result.Content.ReadAsStringAsync().ContinueWith(y =>
        {
            Console.WriteLine(y.Result);
        }))
        .Wait();
}