HttpClient Get call returning statuscode 401 unauthoriszed In C#

Question

I'm trying to make a HttpClient Call through C# by adding some headers. The request is working fine by throwing the empty result as expected with 200 status code. But the same is not working in C# code. My code is like below :

public static Response TestAbcAPICall()
        {
            Response response = new Response();

            try
            {
                var endpoint = "https:/abc.com/path/?script=435&deploy=1&type=vendor&id=9797";

                
                using (var client = new System.Net.Http.HttpClient())
                {
                    client.BaseAddress = new Uri(endpoint);
                    //way - 1 Adding Authorization header

                    var authenticationHeaderValue = new AuthenticationHeaderValue("Authorization", "NLAuth nlauth_account=1249484_SKB1, nlauth_email=restletuser1@org.in, nlauth_signature=Breaths123!, nlauth_role=4444");
                    client.DefaultRequestHeaders.Authorization = authenticationHeaderValue;

                    // Adding contennt-type header
                    client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

                    var getTask = client.GetAsync(endpoint);
                    getTask.Wait();
                    var result = getTask.Result;

                    if (result.IsSuccessStatusCode)
                    {
                        var RESULTS = result.Content.ReadAsStringAsync().Result;
                        //response = JsonConvert.DeserializeObject<Response>(RESULTS);
                        if (response.flag)
                        {
                            response.flag = true;
                        }
                        else
                        {
                            response.flag = false;
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                response.message = ex.Message;
                response.flag = false;
            }

            return response;
        }

Reference ARC worrking with 200 status Image :

client.BaseAddress Is not needed to be set, you already have a full address. — Alen.Toma, Nov 30 '20 at 16:39
@Alen.Toma Yes of course Thank you, Commented it. still facing the same.. — Srikanth Reddy, Nov 30 '20 at 16:42
The working code is using HTTPS (secure). Are you getting any response with c#? If you are not getting a response than the TLS authentication is failing which occurs before a request is sent. The normal solution is to specify the TLS version : ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12; — jdweng, Nov 30 '20 at 16:45
I think hes gettings response, Try and see what is the response Eg `result.StatusCode == HttpStatusCode.Unauthorized` And also this is Get request so you dont need to set `application/json` you are aready reading it as a string — Alen.Toma, Nov 30 '20 at 16:50
Yes, Within "getTask" I'm getting the "result.IsSuccessStatusCode" as "false" — Srikanth Reddy, Nov 30 '20 at 16:51
@Alen.Toma , The result of "result.StatusCode == HttpStatusCode.Unauthorized" is true. — Srikanth Reddy, Nov 30 '20 at 16:57
Then you are doing somthing wrong with your Authorization. and there is the problem. — Alen.Toma, Nov 30 '20 at 16:59
What would be wrong. Because the things I'm passing to ARC or postman passing the same things as headers. — Srikanth Reddy, Nov 30 '20 at 17:02

score 0 · Answer 1 · answered Nov 30 '20 at 16:52

0

Your AuthenticationHeaderValue auth header will look like this when the request is sent:

Authorization: Authorization NLAuth nlauth_account=1249484_SKB1, nlauth_email=restletuser1@org.in, nlauth_signature=Breaths123!, nlauth_role=4444

As you can see the duplicate Authorization breaks it.

Instead use:

client.DefaultRequestHeaders.TryAddWithoutValidation("Authorization", "NLAuth nlauth_account=1249484_SKB1, nlauth_email=restletuser1@org.in, nlauth_signature=Breaths123!, nlauth_role=4444");

As an aside you are really only supposed to create a single HttpClient instance and reuse it throughout the lifetime of your app.

answered Nov 30 '20 at 16:52

Alex K.

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When I implemented your code, it's throwing 400 status code, Bad request. – Srikanth Reddy Nov 30 '20 at 17:00
Run Fiddler and capture the raw request, something will be different when compared to the Postman post. – Alex K. Nov 30 '20 at 17:03
As I observed through quick watch in "client" object It's taking empty for "Authorization". – Srikanth Reddy Nov 30 '20 at 17:05
But, What you said is correct, About appending "Authorization" to the value. – Srikanth Reddy Nov 30 '20 at 17:10
When I tested with fiddler, I observed "Accept: application/json" But we need to pass it as "content-type". – Srikanth Reddy Nov 30 '20 at 18:31

score 0 · Answer 2 · answered Dec 01 '20 at 03:52

Your Auth should look like below

var authenticationHeaderValue = new AuthenticationHeaderValue("NLAuth", "nlauth_account=1249484_SKB1, nlauth_email=restletuser1@org.in, nlauth_signature=Breaths123!, nlauth_role=4444");
                    client.DefaultRequestHeaders.Authorization = authenticationHeaderValue;

Or

var authenticationHeaderValue = new AuthenticationHeaderValue("NLAuth nlauth_account=1249484_SKB1, nlauth_email=restletuser1@org.in, nlauth_signature=Breaths123!, nlauth_role=4444");
                    client.DefaultRequestHeaders.Authorization = authenticationHeaderValue;

There is already post on stackoverflow that cover this issue here

Toma , The first one made to add header but giving 401 unauthorized response. The second one not even accepting as header, Instead throwing exception like format is invalid. — Srikanth Reddy, Dec 01 '20 at 05:31

HttpClient Get call returning statuscode 401 unauthoriszed In C#

2 Answers2