C# unsupported grant type when calling web api
C#Wpfasp.net Web-ApiHttpclientTokenC# Problem Overview
I am trying to perform a Post to my WebAPI from a c# WPF desktop app.
No matter what I do, I get
> {"error":"unsupported_grant_type"}
This is what I've tried (and I've tried everything I could find):
Also dev web api currently active for testing: http://studiodev.biz/
base http client object:
var client = new HttpClient()
client.BaseAddress = new Uri("http://studiodev.biz/");
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("text/plain"));
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("*/*"));
with the following send methods:
var response = await client.PostAsJsonAsync("token", "{'grant_type'='password'&'username'='username'&'password'='password'");
var response = await client.PostAsJsonAsync("token", "grant_type=password&username=username&password=password");
After that failed, I did some googling and tried:
LoginModel data = new LoginModel(username, password);
string json = JsonConvert.SerializeObject(data);
await client.PostAsync("token", new JsonContent(json));
same result, so I tried:
req.Content = new StringContent(json, Encoding.UTF8, "application/x-www-form-urlencoded");
await client.SendAsync(req).ContinueWith(respTask =>
{
Application.Current.Dispatcher.Invoke(new Action(() => { label.Content = respTask.Result.ToString(); }));
});
Note: I can make a successful call with Chrome.
Update Fiddler Result
Could someone please help me make a successful call to the above web api... Please let me know if I can help clarify. Thanks!!
C# Solutions
Solution 1 - C#
The default implementation of OAuthAuthorizationServerHandler
only accepts form encoding (i.e. application/x-www-form-urlencoded
) and not JSON encoding (application/JSON
).
Your request's ContentType
should be application/x-www-form-urlencoded
and pass the data in the body as:
grant_type=password&username=Alice&password=password123
i.e. not in JSON format.
The chrome example above works because it is not passing data as JSON. You only need this for getting a token; for other methods of your API you can use JSON.
This kind of problem is also discussed here.
Solution 2 - C#
-
Note the URL: "localhost:55828/token" (not "localhost:55828/API/token")
-
Note the request data. Its not in json format, its just plain data without double quotes. "userName=[email protected]&password=Test123$&grant_type=password"
-
Note the content type. Content-Type: 'application/x-www-form-urlencoded' (not Content-Type: 'application/json')
-
When you use javascript to make post request, you may use following:
$http.post("localhost:55828/token", "userName=" + encodeURIComponent(email) + "&password=" + encodeURIComponent(password) + "&grant_type=password", {headers: { 'Content-Type': 'application/x-www-form-urlencoded' }} ).success(function (data) {//...
See screenshots below from Postman:
Solution 3 - C#
Here is a working example I used to make this request of my local Web API application running on port 43305 using SSL. I put the project on GitHub as well. https://github.com/casmer/WebAPI-getauthtoken
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Newtonsoft.Json;
using System.Net.Http;
using System.Web;
namespace GetAccessTokenSample
{
class Program
{
private static string baseUrl = "https://localhost:44305";
static void Main(string[] args)
{
Console.WriteLine("Enter Username: ");
string username= Console.ReadLine();
Console.WriteLine("Enter Password: ");
string password = Console.ReadLine();
LoginTokenResult accessToken = GetLoginToken(username,password);
if (accessToken.AccessToken != null)
{
Console.WriteLine(accessToken);
}
else
{
Console.WriteLine("Error Occurred:{0}, {1}", accessToken.Error, accessToken.ErrorDescription);
}
}
private static LoginTokenResult GetLoginToken(string username, string password)
{
HttpClient client = new HttpClient();
client.BaseAddress = new Uri(baseUrl);
//TokenRequestViewModel tokenRequest = new TokenRequestViewModel() {
//password=userInfo.Password, username=userInfo.UserName};
HttpResponseMessage response =
client.PostAsync("Token",
new StringContent(string.Format("grant_type=password&username={0}&password={1}",
HttpUtility.UrlEncode(username),
HttpUtility.UrlEncode(password)), Encoding.UTF8,
"application/x-www-form-urlencoded")).Result;
string resultJSON = response.Content.ReadAsStringAsync().Result;
LoginTokenResult result = JsonConvert.DeserializeObject<LoginTokenResult>(resultJSON);
return result;
}
public class LoginTokenResult
{
public override string ToString()
{
return AccessToken;
}
[JsonProperty(PropertyName = "access_token")]
public string AccessToken { get; set; }
[JsonProperty(PropertyName = "error")]
public string Error { get; set; }
[JsonProperty(PropertyName = "error_description")]
public string ErrorDescription { get; set; }
}
}
}
Solution 4 - C#
If you are using RestSharp, you need to make the request like this:
public static U PostLogin<U>(string url, Authentication obj)
where U : new()
{
RestClient client = new RestClient();
client.BaseUrl = new Uri(host + url);
var request = new RestRequest(Method.POST);
string encodedBody = string.Format("grant_type=password&username={0}&password={1}",
obj.username,obj.password);
request.AddParameter("application/x-www-form-urlencoded", encodedBody, ParameterType.RequestBody);
request.AddParameter("Content-Type", "application/x-www-form-urlencoded", ParameterType.HttpHeader);
var response = client.Execute<U>(request);
return response.Data;
}
Solution 5 - C#
Had same issues but only resolved mine over secured HTTP for the token URL. See sample httpclient code. Ordinary HTTP just stop working after server maintenance
var apiUrl = "https://appdomain.com/token"
var client = new HttpClient();
client.Timeout = new TimeSpan(1, 0, 0);
var loginData = new Dictionary<string, string>
{
{"UserName", model.UserName},
{"Password", model.Password},
{"grant_type", "password"}
};
var content = new FormUrlEncodedContent(loginData);
var response = client.PostAsync(apiUrl, content).Result;
Solution 6 - C#
it my case, i m forget install install package Token.JWT, so you need install too in your project. Install-Package System.IdentityModel.Tokens.Jwt -Version 6.7.1
Solution 7 - C#
It may be the cause of protocol it's required https://