Not receiving response after PostAsync

Question

I have next part of code :

using (var client = new HttpClient()) // from Windows.Web.Http;
{
    //setup client
    var tokenUri = new Uri(apiBaseUri + "/token");
    client.DefaultRequestHeaders.Accept.Clear();
    client.DefaultRequestHeaders.Accept.Add(
                        new HttpMediaTypeWithQualityHeaderValue("application/json"));

    //setup login data
    IHttpContent formContent = new HttpFormUrlEncodedContent(new[]
    {
         new KeyValuePair<string, string>("grant_type", "password"),
         new KeyValuePair<string, string>("username", userName),
         new KeyValuePair<string, string>("password", password),
    });

    //send request
    HttpResponseMessage responseMessage = await client.PostAsync(tokenUri, formContent);

    //get access token from response body
    var responseJson = await responseMessage.Content.ReadAsStringAsync();
    var jObject = JObject.Parse(responseJson);
    return jObject.GetValue("access_token").ToString();
}

This makes call to my Web Api. I have checked if it's really works with fiddler - as result I can see response what i espect (Bearer token). But in code this response are never received.

What is the problem?

@AndyWiesendanger, nothing... Maybe i should set some timeout to be sure, but i wait a lot of time and nothing happens — demo, Nov 10 '15 at 16:21
How are you calling this method? Are you blocking it with `Task.Result`? — Yuval Itzchakov, Nov 10 '15 at 16:21
@YuvalItzchakov than yes `var token = GetAPIToken(UserName, Password, ApiBaseUri).Result;` something like this — demo, Nov 10 '15 at 16:25

score 3 · Accepted Answer · answered Nov 10 '15 at 16:27

This:

var token = GetAPIToken(UserName, Password, ApiBaseUri).Result;

Causes a classic deadlock. You shouldn't be blocking on async code with Task.Result or Task.Wait. Instead, you need to go "async all the way" and await on it too, making the method higher up the call stack async Task as well:

public async Task GetApiTokenAsync()
{
    var token = await GetAPIToken(UserName, Password, ApiBaseUri);
}

Not receiving response after PostAsync

1 Answers1