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Didn't get response from GetAsync API of HttpClient in MVC applications

I am facing an issue regarding not getting response from GetAsync API of HttpClient in MVC Applications(Target Framework - .Net Framework 4.7) whereas getting response in web services and console applications with same snippet. Here I have attached code snippet which I am trying to execute.
public void Get()
{
var response = Gettasks().Result;
}
public static async Task<HttpResponseMessage> GetTasks()
{
var response = new HttpResponseMessage();
try
{
using (var client = new HttpClient())
{
response = await client.GetAsync("https://www.google.com");
}
}
catch (Exception exception)
{
Console.WriteLine(exception.Message);
}
return response;
}
I am getting stuck on response = await client.GetAsync("https://www.google.com"); this line and not getting any response after executing this statement.
If anyone can please suggest solution for this or provide fix/solution which works for you.

You're seeing a deadlock because the code is blocking on an asynchronous method.
The best fix is to remove the blocking:
public async Task Get()
{
var response = await Gettasks();
}
This deadlock happens because await captures a context, and ASP.NET (pre-Core) has a context that only allows one thread at a time, and the code blocks a thread (.Result) in that context, which prevents GetTasks from completing.
Both the context and the blocking are necessary to see this kind of deadlock. In the other scenarios, there is no context, so that is why the deadlock does not occur. Since ASP.NET (pre-Core) has a context, the proper solution here is to remove the blocking.

Not sure whether you have tried following which is working for me.
using (HttpClient client = new HttpClient())
{
client.BaseAddress = new Uri(Environment.GetEnvironmentVariable("BaseAddress"));
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
var requestUri = Environment.GetEnvironmentVariable("Uri");
HttpResponseMessage response = await client.GetAsync(requestUri);
if (response.IsSuccessStatusCode)
{
var data = await response.Content.ReadAsStringAsync();
}
}

C# HttpClient.PostAsync and await crashing app

I am quite new to C#. I'm using the await keyword to invoke HttpClient's API.
static async Task<HttpResponseMessage> CreateChannel(string channelName)
{
try
{
HttpClient client = new HttpClient();
var req = new
{
id= channelName
};
StringContent content = new StringContent(JsonConvert.SerializeObject(req).ToString(), Encoding.UTF8, "application/json");
HttpResponseMessage response = await client.PostAsync("http://localhost:3000/channel", content);
response.EnsureSuccessStatusCode();
return response;
}
catch (Exception ex)
{
...
var view = new Dialog();
...
var result = await DialogHost.Show(view);
return null;
}
}
private void initSocketIo(string channel)
{
CreateChannel(channel).Wait();
...
// after this method we init UI etc.
}
I have 2 problems which I can't seem to be able to solve
After the client.PostAsync() method runs, my app just crashes. Simple as that. I understand it's because the main thread doesn't have anything else to process, but all the code above happens in the constructor code of MainWindow, so there is a lot more to do after the await
The exception is never triggered. How do I ensure that my exception catch clause is invoked in client.PostAsync() throws an exception.
Any code suggestion that just works would do :).

You are mixing blocking calls (.Result, .Wait()) with async calls which can lead to deadlocks.
Make initSocketTo async.
private async Task initSocketIo(string channel) {
var response = await CreateChannel(channel);
...
// after this method we init UI etc.
}
Also do not try to do async in the constructor. Move the heavier processes later in the life cycle. You could even raise an event and handle that on another thread so as not to block the flow.

Async method to make an http call using HttpClient never comes back

I have the following piece of code in a domain service:
HttpClient client = new HttpClient();
client.GetAsync("http://somewebsite.com").Result;
Which works fine, I can place a break point on followed lines and they do hit and all is good. However, I have the same line of code in a nuget package installed in this very same project. There there's the exact same http call:
public class Client : Base
{
public Task<List<Stuff>> GetAsync()
{
return SendMessageAsync(HttpMethod.Get, "http://getstuff.com")
.ContinueWith(x => JsonConvert.DeserializeObject<List<StuffView>>(x.Result.Content.ReasAsStringAsync().Result);
}
}
public class Base
{
HttpClient client:
public Base(HttpClient client)
{
this.client = client:
}
protected async Task<HttpResponseMessage> GetMessageAsync(BttpMethod method, string url)
{
var request = CreateRequestAsync(method, url);
request.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
var response = await client.SendAsync(request); //line 1
return response; // Line 2
}
protected HttpRequestMessage CreateRequestAsync(HttpMethod method, string url)
{
var request = new HttpRequestMessage(method, url);
request.SetBearerToken(myAccessTokenProvider);
return request;
}
}
This is how my domain service is using the nuget package code:
var client = factory.Create();
client.GetAsync().Result;
Debugging this code shows that inside Base class line 1 is hit but line 2 never does. Searching on internet it seems like a thread deadlock issue. So my question is, assuming it's a deadlock, why the heck the first http call in domain service works but not the second one that uses the nuget package code?!
HttpClient deadlock issue:
HttpClient.GetAsync(...) never returns when using await/async

The first example works because either the Task is in the .Completed == true state before you call .Result on it or that line of code has SyncronisationContext.Current == null.
If the task is not in the completed state calling .Result or .Wait() on a task can result in a deadlock if SyncronisationContext.Current != null at the point you called .Result or .Wait(). The best thing to do is mark the entire call stack as async and start returning Task instead of void and Task<T> where you return T then calling await on all places you used .Result or .Wait().
If you are not willing to make those code changes you must switch to using non async methods, this will requite switching from HttpClient to WebClient and using it's non async method calls to do your requests.

Do not use .Result. With .Result, the I/O is started (asynchronously) where the calling thread (synchronously) blocks waiting for it to complete.
Just use await.
var stuff = await client.GetAsync();

Create a safe-threaded client library to connect to an external API

Sorry for the name of my post but I am going to try to explain my problem.
I am building a client library to request an external API and I try to figure out how to make the methods of my library safe-threaded.
Basically the main class of my library looks like this :
public class MyCompanyApiClient
{
private readonly HttpClient _httpClient;
public MyCompanyApiClient(string baseUrl)
{
_httpClient = new HttpClient() {BaseAddress = new Uri(baseUrl)};
_httpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
}
public async Task<MyClassB> PostData(int id, MyClassA dataToPost)
{
var request = new HttpRequestMessage(HttpMethod.Post, $"objects/{id}");
request.Content = new StringContent(JsonConvert.SerializeObject(dataToPost), Encoding.UTF8,
"application/json");
var response = await _httpClient.SendAsync(request);
response.EnsureSuccessStatusCode();
var stringContent = await response.Content.ReadAsStringAsync();
return JsonConvert.DeserializeObject<MyClassB>(stringContent);
}
public async Task<MyClassA > GetById(int id)
{
...
}
}
I'd like to ensure that any instance members of my client class are safe-threaded.
For the moment I plan to wrap the code inside each method into a Task.Run:
public async Task<MyClassB> PostData(int id, MyClassA dataToPost)
{
return await Task.Run(async () =>
{
var request = new HttpRequestMessage(HttpMethod.Post, $"objects/{id}");
request.Content = new StringContent(JsonConvert.SerializeObject(dataToPost), Encoding.UTF8,
"application/json");
var response = await _httpClient.SendAsync(request);
var stringContent = await response.Content.ReadAsStringAsync();
return JsonConvert.DeserializeObject<MyClassB>(stringContent);
});
}
By the way I don't even know if it is going to ensure this method to be safe-threaded.
Any help aprreciated ^^

Thread-safe doesn't mean multi-threading.
It means that some code is aware that it'll be used in multi-threaded cases, and they won't get corrupted, won't produce deadlocks and other threading-related issues.
Sometimes there's code that it's thread-safe per se, while sometimes you need to use thread-synchronization approaches like monitors, mutexes, reset events, semaphores and others, to protect critical code sections from being executed by one, two or n threads at once in order to avoid, again, deadlocks, corruptions and, basically, unexpected behaviors.
In your case, it seems like you consider thread-safe launching your PostDataas a thread in the thread pool. This is a bad choice, you don't need a new thread for this.

Application enter in a "wait status" while HttpRequest operation

I'm doing an HttpRequest to an Url that returns me an xml content. So I try to make an asynchronous request but during this request the application is stopped (pause) and it seems that it cannot get a response (the url inside a browser works perfectly and it returns what I expected).
Here is my code:
public static async Task<String> getResponse(String url)
{
HttpClient httpClient = new HttpClient();
HttpResponseMessage request = await httpClient.GetAsync(url);
String stream = await request.Content.ReadAsStringAsync();
return stream;
}
and I take this with:
String response = UtilityClass.getResponse(requestUrl).Result;
Anyone can help me please?

What happends here is a deadlock. Without too much information i see you're blocking on an asynchronous operation when calling
string response = UtilityClass.getResponse(requestUrl).Result
What happends is when you await inside getResponse, the TaskAwaitable being generated captures your SynchronizationContext in order to marshal the continuation back on to the same context in which it was called. But, when it trys to marshal work bacl to the captured context it cant, because Result is blocking the thread. This is why you should never block on async code. This can be fixed by using ConfigureAwait(false) which tells the TaskAwaitable not to marshal the continuation back and simply execute on the current thread that invoked it:
public static async Task<String> getResponse(String url)
{
HttpClient httpClient = new HttpClient();
HttpResponseMessage request = await httpClient.GetAsync(url).ConfigureAwait(false);
String stream = await request.Content.ReadAsStringAsync().ConfigureAwait(false);
return stream;
}
Another solution, which is better IMO, is to use the async method properly and await on it, instead of block:
string response = await UtilityClass.getResponse(requestUrl)
That would require you to add the async keyword to the calling method. If you cant, maybe a synchronous http request might be the better solution.
Edit
To quote #EricLippert comment which makes this easier to understand:
The key thing to understand here is that result = task.Result; means do nothing else until the result is available, and result = await task; means do something else until the result is available. Both turn a Task<string> into a string, but one blocks and the other does not
There are many good posts explaining the fundamental s of async/await:
Asynchronous Programming with Async and Await
Asynchrony in C# 5 Series (Eric Lippert)
Async Await Intro (Stephan Cleary)
Async Await FAQ