JSON Object and Simple Type to Model in WebAPI using FromBody

Question

I am creating a Web Api method that should accept a JSON Object and a Simple Type. But all parameters are always null.

My json looks like

{
"oldCredentials" : {
    "UserName" : "user",
    "PasswordHash" : "myCHqkiIAnybMPLzz3pg+GLQ8kM=",
    "Nonce" : "/SeVX599/KjPX/J+JvX3/xE/44g=",
    "Language" : null,
    "SaveCredentials" : false
},
"newPassword" : "asdf"}

And my Code looks like:

[HttpPut("UpdatePassword")]
[Route("WebServices/UsersService.svc/rest/users/user")]
public void UpdatePassword([FromBody]LoginData oldCredentials, [FromBody]string newPassword)
{
  NonceService.ValidateNonce(oldCredentials.Nonce);

  var users = UserStore.Load();
  var theUser = GetUser(oldCredentials.UserName, users);

  if (!UserStore.AuthenticateUser(oldCredentials, theUser))
  {
    FailIncorrectPassword();
  }

  var iv = Encoder.GetRandomNumber(16);
  theUser.EncryptedPassword = Encoder.Encrypt(newPassword, iv);
  theUser.InitializationVektor = iv;

  UserStore.Save(users);
}

Answer 1

The current JSON you are sending maps to the following classes

public class LoginData {
    public string UserName { get; set; }
    public string PasswordHash { get; set; }
    public string Nonce { get; set; }
    public string Language { get; set; }
    public bool SaveCredentials { get; set; }
}

public class UpdateModel {
    public LoginData oldCredentials { get; set; }
    public string newPassword { get; set; }
}

[FromBody] can only be used once in action parameters

[HttpPut("WebServices/UsersService.svc/rest/users/user")]
public void UpdatePassword([FromBody]UpdateModel model) {
    LoginData oldCredentials = model.oldCredentials;
    string newPassword = model.newPassword;
    NonceService.ValidateNonce(oldCredentials.Nonce);

    var users = UserStore.Load();
    var theUser = GetUser(oldCredentials.UserName, users);

    if (!UserStore.AuthenticateUser(oldCredentials, theUser)) {
        FailIncorrectPassword();
    }

    var iv = Encoder.GetRandomNumber(16);
    theUser.EncryptedPassword = Encoder.Encrypt(newPassword, iv);
    theUser.InitializationVektor = iv;

    UserStore.Save(users);
}

Answer 2

As per the Parameter Binding in ASP.NET Web API, "At most one parameter is allowed to read from the message body". Means only one parameter can contain [FromBody]. So in this case it will not work. Create one complex object and add required properties to it. You can add newPassword to your complex object to make it work.