Web Api token authorization

Question

Hi I tried to access a third party web api(http://some domain) which is having Key ,Value , tried with postman tool its working by passing key, value but how to validate that authorization and get data in asp.net code behind thanks in advance

Sai Kumar Koona · Answer

Hi Sai, Can you please check the below sample code where we are including token details in the HTTP call. public async Task string > GetAPI( string apiPath) { var baseUri = new Uri( "https://api.twitter.com/" ); var encodedConsumerKey = HttpUtility.UrlEncode( "111111111111" ); var encodedConsumerKeySecret = HttpUtility.UrlEncode( "222222222222" ); var encodedPair = Base64Encode(String.Format( "{0}:{1}" , encodedConsumerKey, encodedConsumerKeySecret)); var requestToken = new HttpRequestMessage { Method = HttpMethod.Post, RequestUri = new Uri(baseUri, "oauth2/token" ), Content = new StringContent( "grant_type=client_credentials" ) }; requestToken.Content.Headers.ContentType = new MediaTypeWithQualityHeaderValue( "application/x-www-form-urlencoded" ) { CharSet = "UTF-8" }; requestToken.Headers.TryAddWithoutValidation( "Authorization" , String.Format( "Basic {0}" , encodedPair)); var bearerResult = await HttpClient.SendAsync(requestToken); var bearerData = await bearerResult.Content.ReadAsStringAsync(); var bearerToken = JObject.Parse(bearerData)[ "access_token" ].ToString(); var requestData = new HttpRequestMessage { Method = HttpMethod.Get, RequestUri = new Uri(baseUri, apiPath), }; requestData.Headers.TryAddWithoutValidation( "Authorization" , String.Format( "Bearer {0}" , bearerToken)); var results = await HttpClient.SendAsync(requestData); return await results.Content.ReadAsStringAsync(); }

Contact Enrika · Answer

God bless ya, @sai-kumar51... that method you posted undoubtedly saved me 16+hours of work, and several years off an early death. We're working on a DocuSign integration, and their sample programs and code examples make me want to slit my throat... I've not the slightest idea why their C# oauth sample code doesn't contain this exact code right here... the only alteration I had to make for our configuration was to remove the 'await's, and it was like a little miracle. God bless ya, son, God bless ya.

Rajeesh Menoth · Answer

Hi, You must add authorization or your credential in the header. In your code authorization header is empty and for that reason your are getting 401 error. Reference : https://www.c-sharpcorner.com/article/cognitive-services-extract-handwritten-text-from-an-image-using-computer-visio/ https://stackoverflow.com/questions/4675166/asp-net-http-authorization-header https://docs.microsoft.com/en-us/aspnet/web-api/overview/security/basic-authentication https://forums.asp.net/t/1756594.aspx?Howto+pass+Authorisation+token+in+GET+POST+REQUEST+Header+to+webservice Mark as answer, if that helped you

Ashok · Answer

Thanks for reply saikumar,already i have key, value to authenticate web api but how can we check through code static void Main(string[] args) { HttpClient client = new HttpClient(); client.BaseAddress = new Uri("http://server01:80"); client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json")); HttpResponseMessage response = client.GetAsync("api/products").Result; if (response.IsSuccessStatusCode) { var products = response.Content.ReadAsAsync >().Result; foreach (var p in products) { Console.WriteLine("{0}	{1};	{2}", p.Name, p.Price, p.Category); } } else { Console.WriteLine("{0} ({1})", (int)response.StatusCode, response.ReasonPhrase); //Get 401 unauthorized error here. } Console.ReadKey(); }

Sai Kumar Koona · Answer

Hi Sai, as you already verified the given API is working as expected using postman tool. You can use HttpClient object to access the same web API from the server side. Please read the following article for more practical implementation. https://www.c-sharpcorner.com/article/calling-web-api-using-httpclient/