CODEWITHSUNDEEP
c#asp.netasp.net-mvcasp.net-core
JianYA
JianYA

Reputation: 3024

.NET Core 2.1 HttpClient doesn't return expected values

I am using an interface to call an api from this url http://localhost:55260/api/Accounts/GetList

This is the controller its referencing:

[HttpGet]
[Route("GetList")]
[AllowAnonymous]
public ActionResult<IEnumerable<string>> GetList()
{
    return new string[] { "value1", "value2" };
}

However, instead of the strings returning, I'm getting this:

enter image description here

This is how I'm declaring my httpclient/interface:

private readonly HttpClient httpClient;
public AuthenticationClient(HttpClient httpClient)
{
    httpClient.BaseAddress = new Uri("http://localhost:55260/api/Accounts");
    httpClient.DefaultRequestHeaders.Accept.Clear();
    httpClient.DefaultRequestHeaders.Accept.Add(
        new MediaTypeWithQualityHeaderValue("application/json"));
    this.httpClient = httpClient;
}

public async Task<IEnumerable<string>> GetDataAsync()
{
    List<string> result = null;
    HttpResponseMessage response = await httpClient.GetAsync("/GetList");
    if (response.IsSuccessStatusCode)
    {
        result = await response.Content.ReadAsAsync<List<string>>();
    }
    return result;
}

I have already declared it in my Startup.cs as services.AddHttpClient();

This is how I call the interface

private readonly IAuthenticationClient authenticationClient;
public HomeController(IAuthenticationClient authenticationClient)
{
    this.authenticationClient = authenticationClient;
}

public IActionResult Index()
{
    var result = authenticationClient.GetData();
    return View();
}

Have I missed something or is there a tutorial on how to use HttpClients? Also, how do I post data through this?

Upvotes: 4

Views: 888

Answers (3)

Janmejay Kumar
Janmejay Kumar

Reputation: 319

ASP.NET Core 2.1 includes a new IHttpClientFactory service that makes it easier to configure and consume instances of HttpClient in apps. HttpClient already has the concept of delegating handlers that could be linked together for outgoing HTTP requests. The factory:

  • Makes registering of instances of HttpClient per named client more intuitive.
  • Implements a Polly handler that allows Polly policies to be used for Retry, CircuitBreakers, etc.

For more information, see Initiate HTTP Requests.

Upvotes: 0

Ryan
Ryan

Reputation: 20106

I make it when I change controller code to

public async Task<IActionResult> Index()
    {
        var result = await _authenticationClient.GetDataAsync();
        return View();
    }

Modify GetDataAsync()

HttpResponseMessage response = await httpClient.GetAsync("/api/Accounts/GetList");

Upvotes: 0

jazb
jazb

Reputation: 5791

your interface defines an async call. in other words "GetData" returns Task<string> not that actual value.

In order to get the actual values try this (coding free hand so not debugged)

public async Task<IActionResult> Index()
{
    var result = await authenticationClient.GetData();
    return View(result);
}

Upvotes: 4

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