HttpClient in ASP.NET MVC C# is not working on deployment windows server 2016

Kishan Verma 6

HttpClient in ASP.NET MVC C# is not working on deployment windows server 2016 (returns 500 status code) but it perfectly works in local server.
Kindly, may I know, is there something missing to declare before calling APIs with HttpClient? Thank you.

AgaveJoe 29,281 Reputation points

2021-10-12T17:03:22.18+00:00

"Not working" is not descriptive enough to help you solve this problem. Usually when code does not work as expected there is an error. Can you share the error message? Also, share the source code so the community can have an idea of how your code works.

Kishan Verma 6

Thank you. Here is the source code:
The error message shown is 500 status code.

    private async Task<JsonTextReader> GetAllCategories()
    {
        string apiSessionID = Utility.GetCookieByCookieName(ConstantVariables.ApiSessionID);

        using (HttpClient client = new HttpClient())
        {
            client.BaseAddress = new Uri(Category_URI);
            client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
            var response = client.GetAsync(string.Format("GetAllCategories?sessionId={0}", 
            apiSessionID)).ConfigureAwait(false).GetAwaiter().GetResult();
            if (response.IsSuccessStatusCode)
            {
                var contentStream = await response.Content.ReadAsStreamAsync();

                var streamReader = new StreamReader(contentStream);
                var jsonReader = new JsonTextReader(streamReader);

                return jsonReader;
            }
        }

        return null;
    }

MotoX80 35,136 Reputation points

2021-10-12T17:19:21.73+00:00

What site are you to trying to call? What's in Category_URI? If you RDP to the server, can you browse that site?
AgaveJoe 29,281 Reputation points

2021-10-12T17:26:49.723+00:00

The code does not follow any standards but it should work nonetheless.

The key is basic troubleshooting and capturing any error messages. What happens? Does the GetAllCategories() return null, JSON, or throw an exception? If the method throws an exception then what is the error message?

Can you verify the apiSessionID is correct? The ID is in a cookie. Does the cookie exist?

Try using the browser to access GetAllCategories. Does it work?

Verify Category_URI is correct for the published app.
MotoX80 35,136 Reputation points

2021-10-12T17:27:53.12+00:00

There's also no Try/Catch in your code. You only test for IsSuccessStatusCode. You can't just ignore errors. If you encounter an error you need to do something to inform the end user that there was a problem.
Bruce (SqlWork.com) 69,881 Reputation points

2021-10-12T17:42:10.13+00:00

the error is from the server being called. you should log the response so you can debug. also if you have proper logging on the service you call, you shod be able to debug from that side.

1 answer

Limitless Technology 39,786 Reputation points

2021-10-13T08:49:11.707+00:00

Hi there,

Web API apps typically use several HTTP verbs: GET, POST, PUT, DELETE, and sometimes PATCH. That being said, developers may run into situations where those verbs are implemented by another IIS module on their production IIS server, which leads to a situation where a Web API controller that works correctly in Visual Studio or on a development server will return an HTTP 405 error when it is deployed to a production IIS server.

You can Troubleshoot Web API2 apps that work in Visual Studio and fail on a production IIS server from here https://learn.microsoft.com/en-us/aspnet/web-api/overview/testing-and-debugging/troubleshooting-http-405-errors-after-publishing-web-api-applications

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