Avoiding Deadlock with HttpClient

Question

What is the best way to use HttpClient and avoid deadlock? I am using the code below, called entirely from synchronous methods, but I concerned it maybe causing

Answer 1

In my case, when I used await client.GetAsync(), I didnot receive any response, when I tried to observe the problem, the debugger also terminated on the above GetAsync() line. I could only use client.GetAsync().Result to get the reponse correctly, but I saw many saying that it may lead to deadlock like in this post and it is synchronous too. I was particularly using this in UI button click event as well, which is not recommended.

Finally, I got it working by adding the below three lines, I didnot have those three lines before (maybe that was the problem):

using (var client = new HttpClient())
{    
  string relativeURL = "api/blah";
  //These three lines - BaseAddress, DefaultRequestHeaders and DefaultRequestHeaders
  client.BaseAddress = new Uri(Constants.ServiceBaseAddress);
  client.DefaultRequestHeaders.Clear();
  client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
  HttpResponseMessage response = await client.GetAsync(relativeURL);
  ...
}

NOTE:

1. The ServiceBaseAddress must end with slash (/) and relative URL must begin without slash (/)
2. Sample of my Constants.ServiceBaseAddress is https://domainname.org/

This is working fine now, with async signature and no deadlock worries. Hope this helps somebody.