Calling WEB API with basic authentication in C#

Question

I have a working WEB API that I wrote, and I added basic authentication to the API (username is "testing", password is "123456"). However, when trying to call that API from my web form, I keep getting the "(401) Unauthorized" message. What should I change in the web code to call the API successfully?

 string url = String.Format("http://example.com"); //here I have the correct url for my API
 HttpWebRequest requestObj = (HttpWebRequest)WebRequest.Create(url);
 requestObj.Method = "Get";
 requestObj.PreAuthenticate = true;
 requestObj.Credentials = new NetworkCredential("testing", "123456");
 HttpWebResponse responseObj = null;
 responseObj = (HttpWebResponse)requestObj.GetResponse();
 string strresult = null;
 using (Stream stream = responseObj.GetResponseStream())
 {
     StreamReader sr = new StreamReader(stream);
     strresult = sr.ReadToEnd();
     sr.Close();
 }

This is what my API searches for in terms of authentication:

actionContext.Request.Headers.Authorization.Parameter

Should I be adding a header instead of NetworkCredential or is it the same thing?

score 31 · Accepted Answer · edited Mar 14 '23 at 09:08

This should help:

HttpMessageHandler handler = new HttpClientHandler();
    
var httpClient = new HttpClient(handler)
{
     BaseAddress = new Uri(url),
     Timeout = new TimeSpan(0, 2, 0)
};
    
httpClient.DefaultRequestHeaders.Add("ContentType", "application/json");
    
//This is the key section you were missing    
var plainTextBytes = System.Text.Encoding.UTF8.GetBytes("testing:123456");
string val = System.Convert.ToBase64String(plainTextBytes);
httpClient.DefaultRequestHeaders.Add("Authorization", "Basic " + val);
    
HttpResponseMessage response = httpClient.GetAsync(url).Result;
string content = string.Empty;
    
using (StreamReader stream = new StreamReader(response.Content.ReadAsStreamAsync().Result, System.Text.Encoding.GetEncoding(_encoding)))
{
     content = stream.ReadToEnd();
}

score 4 · Answer 2 · answered Aug 27 '19 at 13:59

4

This is the line I needed:

requestObj.Headers["Authorization"] = "Basic " + Convert.ToBase64String(Encoding.Default.GetBytes("username:password"));

answered Aug 27 '19 at 13:59

Maya Berk

177
1
1
11

Martinus Suherman · Answer 3 · 2021-06-23T11:37:42.810

1

I just found out that with .NET Core 3.1 you could do it like this:

    HttpRequestMessage request = new HttpRequestMessage(
        HttpMethod.Post,
        "your-api-url-here");

    request.Headers.Authorization = new BasicAuthenticationHeaderValue(username, password);

edited Jun 23 '21 at 11:37

answered Jun 18 '21 at 08:10

Martinus Suherman

44
4

score 0 · Answer 4 · answered Aug 26 '19 at 22:10

I think your API might need a header being added to it (if you haven't done so already). Take a look at this article: https://en.wikipedia.org/wiki/Basic_access_authentication#Client_side

But essentially, your API will need an Authorization header added to it. The Authorization key will contain the word Basic followed by a space, then the username and password encrypted using Base64. So in your instance, testing:123456 would be encrypted using base64 as dGVzdGluZzoxMjM0NTY=. So the header record will look like this:

Authorization: Basic dGVzdGluZzoxMjM0NTY=

Thank you very much!! That's what I did – Maya Berk Aug 27 '19 at 13:58 — Maya Berk, Aug 27 '19 at 13:58

score 0 · Answer 5 · answered Jan 02 '20 at 15:11

(Basic Authentication) Here is the other solution to call Authenticated API

 class Program
{
    static void Main(string[] args)
    {
        BaseClient clientbase = new BaseClient("https://website.com/api/v2/", "username", "password");
        BaseResponse response = new BaseResponse();
        BaseResponse response = clientbase.GetCallV2Async("Candidate").Result;
    }


    public async Task<BaseResponse> GetCallAsync(string endpoint)
    {
        try
        {
            HttpResponseMessage response = await client.GetAsync(endpoint + "/").ConfigureAwait(false);
            if (response.IsSuccessStatusCode)
            {
                baseresponse.ResponseMessage = await response.Content.ReadAsStringAsync();
                baseresponse.StatusCode = (int)response.StatusCode;
            }
            else
            {
                baseresponse.ResponseMessage = await response.Content.ReadAsStringAsync();
                baseresponse.StatusCode = (int)response.StatusCode;
            }
            return baseresponse;
        }
        catch (Exception ex)
        {
            baseresponse.StatusCode = 0;
            baseresponse.ResponseMessage = (ex.Message ?? ex.InnerException.ToString());
        }
        return baseresponse;
    }
}


public class BaseResponse
{
    public int StatusCode { get; set; }
    public string ResponseMessage { get; set; }
}

public class BaseClient
{
    readonly HttpClient client;
    readonly BaseResponse baseresponse;

    public BaseClient(string baseAddress, string username, string password)
    {
        HttpClientHandler handler = new HttpClientHandler()
        {
            Proxy = new WebProxy("http://127.0.0.1:8888"),
            UseProxy = false,
        };

        client = new HttpClient(handler);
        client.BaseAddress = new Uri(baseAddress);
        client.DefaultRequestHeaders.Accept.Clear();
        client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
        var byteArray = Encoding.ASCII.GetBytes(username + ":" + password);

        client.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Basic", Convert.ToBase64String(byteArray));

        baseresponse = new BaseResponse();

    }
}

Calling WEB API with basic authentication in C#

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