gistfile1.cs

  struct Panda
    {
        public static string Api_host = "api.pandastream.com";
        public static string Api_version = "/v2";
        public static string Cloud_ID = "yourCloudID";
        public static string Access_key = "yourAccessKey";
        public static string Secret_key = "yourSecretKey";
    }

    [WebMethod]
    public string GetVideoEncodingID_Panda()
    {
        string pandaResponse = string.Empty;
        string videoID = "05102f9acbf2583daa85c6ec186e1635";
        string pTimeStamp = GetTimestamp();

        try
        {
            //generate string to sign
            string stringToSign = "GET\n" +
                Panda.Api_host + "\n" +
                "/videos/" + videoID + "/encodings.json" + "\n" +
                "access_key=" + Panda.Access_key +
                "&cloud_id=" + Panda.Cloud_ID +
                "&timestamp=" + pTimeStamp;

            string signature = EncodeStringToSignAsHMACSHA256(stringToSign, Panda.Secret_key);

            //generate request string
            string callUrl = "http://" + Panda.Api_host +
              Panda.Api_version +
              "/videos/" + videoID + "/encodings.json?" +
              "access_key=" + HttpUtility.UrlEncode(Panda.Access_key) +
              "&cloud_id=" + HttpUtility.UrlEncode(Panda.Cloud_ID) +
              "&timestamp=" + pTimeStamp +
              "&signature=" + HttpUtility.UrlEncode(signature);

            //call Panda API
            HttpWebRequest httpReq = (HttpWebRequest)WebRequest.Create(callUrl);
            httpReq.Method = "GET";
            httpReq.ContentLength = 0;
            HttpWebResponse httpResponse = (HttpWebResponse)httpReq.GetResponse();
            Encoding enc = System.Text.Encoding.GetEncoding(1252);
            StreamReader responseStream = new StreamReader(httpResponse.GetResponseStream(), enc);
            pandaResponse = responseStream.ReadToEnd();
        }
        catch (Exception ex)
        {
        }

        return pandaResponse;
    }

    public string EncodeStringToSignAsHMACSHA256(string stringToSign, string secretKey)
    {
        byte[] toSign = Encoding.UTF8.GetBytes(stringToSign);
        byte[] secret;
        HMAC signer;
        secret = Encoding.UTF8.GetBytes(secretKey);
        signer = new HMACSHA256(secret);
        byte[] sigBytes = signer.ComputeHash(toSign);
        string signature = Convert.ToBase64String(sigBytes);

        return signature;
    }

    private string GetTimestamp()
    {
        DateTime currentTime = DateTime.UtcNow;
        string timestamp = currentTime.ToString("yyyy-MM-ddTHH:mm:ss+00:00");
        return HttpUtility.UrlEncode(timestamp).ToUpper();
    }