CODEWITHSUNDEEP
c#apirestxamarin.forms
Sadra M.
Sadra M.

Reputation: 1532

StatusCode 400 "Bad request" when Connecting a Xamarin.forms app on a physical Phone to an Asp.net REST API

Thanks for your attention. I'm trying to make a Xamarin.Forms App that communicates with a REST API. The API is fully functional, I've tested it with Postman and another WPF project. Upon trying to call a simple GET method with my HttpClient, I get the following HttpResponseMessage

{
    StatusCode: 400, 
    ReasonPhrase: 'Bad Request', 
    Version: 1.1, 
    Content: System.Net.Http.StreamContent, 
    Headers:
    {
        Server: Microsoft-HTTPAPI/2.0
        Date: Sun, 17 May 2020 12:20:37 GMT
        Connection: close
        Content-Type: text/html; charset=us-ascii
        Content-Length: 334
    }
}


public async Task TurnLEDOn()
{
    HttpClient Client = new HttpClient(new System.Net.Http.HttpClientHandler());

    Client.DefaultRequestHeaders.Accept.Clear();
    Client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/Json"));
    Client.BaseAddress = new Uri("https://192.168.1.2:44341/");
    HttpResponseMessage response = await Client.GetAsync("api/ChipCore/TurnLEDOn");
    if (response.IsSuccessStatusCode)
    {
        string receivedPerson = await response.Content.ReadAsAsync<string>();
    }
}

This same code is run by a WPF program and works flawlessly.

Both my phone and Laptop are connected to the same Wi-Fi network.

CHANGE_NETWORK_STATE
CHANGE_WIFI_STATE
ACCESS_NETWORK_STATE
INTERNET

Method in API

[RoutePrefix("api/ChipCore")]
public class ValuesController : ApiController
{
    [HttpGet]
    [Route("TurnLEDOn")]
    public bool TurnLEDOn()
    {
        return Switch.TurnLEDOn();
    }
}

Update

Upvotes: 7

Views: 3888

Answers (4)

Jim W
Jim W

Reputation: 5016

IIS Express cannot process requests from other machines.

You can:

Upvotes: 2

Massaynus
Massaynus

Reputation: 442

assuming that you are running IIS Express in debug mode, it won't allow any connection from outside your computer, I've had the same problem with a WebAPI before

you may wanna try to run your app in a VM or something you should also try accessing the API from another computer, you can test it using your ready WPF app, i believe you'll face the same problem then

you could also try to send postman requests using the Server IP address instead of localhost

If you happen to reproduce the problem this way then all you need is to configure the IIS to server remote/external traffic

Upvotes: 0

DeityWarrior
DeityWarrior

Reputation: 826

The problem looks like your phone is not connected to your server (which is hosted on your computer).

If you are able to access this same request using Postman, it shouldn't be a problem but let's find out.

Step 1) What do your server logs say? When your phone throws a 400 bad request error, did it really even connect to your computer? Just go to your server logs and find out whether was it even hit? If the server was hit, then go to step 2. Else go to step 3 for one more confirmation.

Step 2) Can you compare the request made through postman with the request made through your phone? Both the header and the body? Or with the WPF request? You need to find out what's the different because something definitely is.

Step 3) Can you try one more thing. Just create a new controller at root "/" and send a "Hello world" string in response. Now try accessing the root through your phone and postman. You can directly open it in your phone browser. If it doesn't say "Hello world" then it's confirmed that nothing is wrong with your api but a connection issue b/w your phone and computer.

Upvotes: 0

amitklein
amitklein

Reputation: 1395

Try the following solution.

  1. Right Click Android Project -> Android Options -> Advanced -> Change HttpClientimplementation from Default to Android

Refer to: Xamarin Forms - simple PostAsync() returns error 400 bad request

.

  1. If this solution doesn't work you can try to execute the code that the error occurs only when HttpResponseMessage.IsSuccessStatusCode is satisfied.
if (Resultado.IsSuccessStatusCode)
{
    //
}

Refer to: https://forums.xamarin.com/discussion/comment/391413/#Comment_391413

.

  1. If both of the solutions does not work you can try going to this similar question for more answers

Upvotes: 0

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