Web request from HttpClient stuck

Question

I created http request with HttpClient class.I want to make GET request to some url. For example "http://www.google.com", or another url.

My application hosted in Amazon EC2 and use .Net Core 2.2.

    static HttpClient client = new HttpClient();

    private static async Task HttpClientRequestAsync(string url)
    {
        try
        {
            var response = await client.GetAsync(url);

            string responseJson = await response.Content.ReadAsStringAsync();

            Console.WriteLine(responseJson);
        }
        catch (Exception e)
        {
            Console.WriteLine(e.Message);
        }
    }

I don't know why, but my request stuck in client.GetAsync. After that nothing happens, without any response or exceptions. It is very strangely, because I can see this behavior only on Amazon EC2 instance. In my local machine this request successfully run. When I use Postman or Chrome on EC2 machine and create the same request - I receive response. If i replace HttpClient to WebRequest - I have the same behavior.

Thank you in advance

Minimal reproducible example for Console App:

class Program
{
    static void Main(string[] args)
    {
        HttpClientRequestAsync().GetAwaiter().GetResult();

        Console.ReadLine();
    }

    static HttpClient client = new HttpClient();

    private static async Task HttpClientRequestAsync()
    {
        try
        {
            Console.WriteLine("Your url:");
            var url = Console.ReadLine();

            var response = await client.GetAsync(url);
            string responseJson = await response.Content.ReadAsStringAsync();

            Console.WriteLine(responseJson);
        }
        catch (Exception e)
        {
            Console.WriteLine(e.Message);
        }
    }
}

`HttpClientRequestAsync().GetAwaiter().GetResult();` is your problem, this will be deadlocking — Liam, Aug 06 '19 at 13:07
Possible duplicate of [Is .GetAwaiter().GetResult(); safe for general use?](https://stackoverflow.com/questions/39007006/is-getawaiter-getresult-safe-for-general-use) — Liam, Aug 06 '19 at 13:07
@BugFinder my code don't reach second await in this scenario — Dev123, Aug 06 '19 at 13:08
GetAwaiter().GetResult() it is only example for console application @Liam — Dev123, Aug 06 '19 at 13:11
I can replace HttpClient to WebRequest and behawior will be the same — Dev123, Aug 06 '19 at 13:12
Note you could use [async Task Main](https://blogs.msdn.microsoft.com/mazhou/2017/05/30/c-7-series-part-2-async-main/) for your example. — Jesse de Wit, Aug 06 '19 at 14:13

score 0 · Answer 1 · answered Aug 07 '19 at 13:35

0

Instead of

HttpClientRequestAsync().GetAwaiter().GetResult();

use this:

Task.Run(async () => await HttpClientRequestAsync());

answered Aug 07 '19 at 13:35

user7579919

11
2

score -1 · Accepted Answer · answered Aug 07 '19 at 11:11

-1

Disabling proxy when i created HttpClient helped me: UseProxy = false; Proxy = null;

answered Aug 07 '19 at 11:11

Dev123

53
1
9

Web request from HttpClient stuck

2 Answers2

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