I am using .NET 6 to develop the core Web API, I have a abstract class AdminApiClient inherit ApiClientBase class like below:

public abstract class AdminApiClient : ApiClientBase
{
    protected static HttpClient? client;

    public AdminApiClient()
    {
        client = client ?? new HttpClient
        {
            BaseAddress = new Uri("http://localhost:44355/")
        };
    }

    protected override HttpClient GetHttpClient()
    {
        return client;
    }
}

Below is my ApiClientBase class, When I call the Test method, declare new httpClient inside method is working fine, but when calling GetHttpClient() throw exception.

public abstract class ApiClientBase
{
    protected abstract HttpClient GetHttpClient();

    protected async Task<TResult> Test<TResult>()
    {
        var apiName = "api/users/GetTest";

        var httpClient = new HttpClient();

        httpClient.BaseAddress = new Uri("https://localhost:44355/");

        //working fine
        var response1 = await httpClient.GetAsync(apiName);

        //throw error exception
        var response2 = await GetHttpClient().GetAsync(apiName);
    }
}

I am not sure why using code below is fine.

 var response1 = await httpClient.GetAsync(apiName);

But throw exception when using code below:

var response2 = await GetHttpClient().GetAsync(apiName);

Exception message:

"System.Net.Http.HttpRequestException: An error occurred while sending the request.\r\n ---> System.IO.IOException: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host..\r\n ---> System.Net.Sockets.SocketException (10054): An existing connection was forcibly closed by the remote host.\r\n --- End of inner exception stack trace ---\r\n at System.Net.Sockets.Socket.AwaitableSocketAsyncEventArgs.ThrowException(SocketError error, CancellationToken cancellationToken)\r\n at System.Net.Sockets.Socket.AwaitableSocketAsyncEventArgs.System.Threading.Tasks.Sources.IValueTaskSource<System.Int32>.GetResult(Int16 token)\r\n at System.Net.Http.HttpConnection.InitialFillAsync(Boolean async)\r\n
at System.Net.Http.HttpConnection.SendAsyncCore(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)\r\n --- End of inner exception stack trace ---\r\n at System.Net.Http.HttpConnection.SendAsyncCore(HttpRequestMessage request, Boolea n async, CancellationToken cancellationToken)\r\n at System.Net.Http.HttpConnectionPool.SendWithVersionDetectionAndRetryAsync(HttpRequestMessage request, Boolean async, Boolean doRequestAuth, CancellationToken cancellationToken)\r\n at System.Net.Http.DiagnosticsHandler.SendAsyncCore(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)\r\n at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)\r\n at System.Net.Http.HttpClient.g__Core|83_0(HttpRequestMessage request, HttpCompletionOption completionOption, CancellationTokenSource cts, Boolean disposeCts, CancellationTokenSource pendingRequestsCts, CancellationToken originalCancellationToken)\r\n at Web.Core.ApiClientBase.Test() in C:\Web.Core\ApiClientBase.cs:line 76"

CodePudding user response：

Behaviour is different because the addresses are different:

http://localhost:44355/
https://localhost:44355/

It looks like the API you're connecting to is http only (despite using the https-ish port 44355).

Please note that you should be able to reproduce the issue in your browser by trying to go to both addresses.

CodePudding user response：

IHttpClientFactory.GetHttpClient Method

Method returning an Http client that will be used to communicate with Azure AD. This enables advanced scenarios. See https://aka.ms/adal-net-application-configuration

HttpClient

Provides a class for sending HTTP requests and receiving HTTP responses from a resource identified by a URI.

Note

It sounds like GetHttpClient is used only for Azure Active Directory (Azure AD)