How to Invoke the Azure api from Server Side with C#?

it is quick easy to call Web Api from client side with Ajax or XMLHttpRequest.

but it is also not so hard to implement a server side execution.

we can either use HttpWebReqeust or HttpClient to call Web Api

if you use api to load data, HttpWebRequest Method should be GET.  you can skip
the GetRequestStream part.

if your action send data to server,  HttpWebRequest Method should be POST.
 

the following sample will demonstrate a call to Web API that hosted in Azure.


   public static async Task<APIResult> InvokeAzureAPICall(string url, string inputData)
        {
            try
            {
                HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
                  req.Headers.Add("SubscriptionKey", "KEYFromAzure");

                var cert = new X509Certificate2(File.ReadAllBytes("C:\\Certs\\myCertificate.pfx"), "MYPassword");
                req.ClientCertificates.Add(cert);
   
                // from this line below only required for Post data to server
                //if passing in object are in json format.
                req.ContentType = "application/json";
                req.Method = "POST";
                Encoding encoding = new UTF8Encoding();

                byte[] dataBytes = encoding.GetBytes(inputData);
                req.ContentLength = dataBytes .Length;

                Stream stream = req.GetRequestStream();
                stream.Write(data, 0, dataBytes.Length);
                stream.Close();
              
                //ending here the above is code is required only for Post Method in the web api call. 


                WebResponse resp = await req.GetResponseAsync();

                string response = "";
                using (var readStream = new StreamReader(resp.GetResponseStream()))
                {
                    response = readStream.ReadToEnd();
                }
                return new APIResult
                {
                    apiResponse = response,
                    apiStatusCode = HttpStatusCode.OK
                };
            }
            catch (Exception ex)
            {
                string response = "";
                using (var rdstream = new StreamReader(((System.Net.WebException)ex).Response.GetResponseStream()))
                {
                    response = rdstream.ReadToEnd();
                    return new APIResult
                    {
                        apiResponse = response,
                        apiStatusCode = ((System.Net.HttpWebResponse)((System.Net.WebException)ex).Response).StatusCode
                    };
                }

            }
        }