Unity, C#, VWS API

hi i'm trying to export my image to Cloud Database by VWS API. so i refer some forum and make some code. but it doesn't work.

Please Help me.

If i delete "//" in front of the line 'dicHeader.Add("Date", date);', or 'dicHeader.Add("Host", https://vws.vuforia.com);

Error is 'cannot override specific Headers', and current code's error is "result_code":"fail"," traction_id":"*****"

what is problem?? is vuforia sever broken?? i'm looking for problem almost 2weeks. Please help me

using UnityEngine; using System.Collections; using System.Collections.Generic; using JsonFx.Json; using System.Security.Cryptography; using System.IO; using System.Text; using System; using System.Net; //using UnityEngine.Networking; public class vwsConnectToCloud : MonoBehaviour { public string accessKey = "3de5198ece877f037505************"; public string secretKey = "87ae92f53e764a6aea1a************"; public string url = "https://vws.vuforia.com/targets"; public Texture2D target; string Date = ""; string contentType = "application/json"; // Use this for initialization void Start() { } public void calljpostTarget() { StartCoroutine(jpostTarget()); } // Update is called once per frame void Update() { } IEnumerator jpostTarget() { Date = DateTime.UtcNow.ToString("r"); //Date = DateTime.Now.ToUniversalTime().ToString("r"); Dictionary<string, string> test = new Dictionary<string, string>(); test.Add("name", "myTarget"); test.Add("width", "32.0"); test.Add("image", System.Convert.ToBase64String(target.EncodeToPNG())); string json = JsonWriter.Serialize(test); HttpWebRequest httpWReq = (HttpWebRequest)HttpWebRequest.Create(url); //byte[] rawData = req.data; WWWForm jform = new WWWForm(); jform.AddBinaryData("json", Encoding.UTF8.GetBytes(json)); Dictionary<string, string> dicHeader = new Dictionary<string, string>(); dicHeader = jform.headers; //dicHeader.Add("Host", "vws.vuforia.com"); //dicHeader.Add("Date", Date); //dicHeader.Add("Content-Type", "application/json"); dicHeader["Content-Type"] = contentType; dicHeader.Add("Authorization", "VWS " + accessKey + ":" + signature(secretKey, json)); List<string> test2 = new List<string>(dicHeader.Values); List<string> test3 = new List<string>(dicHeader.Keys); for (int i = 0; i < test2.Count; i++) { Debug.Log("Test Data " + test3[i] + test2[i]); } WWW request = new WWW(url, jform.data, dicHeader); yield return request; print(request.responseHeaders["Date"]); print(request.text); //yield return www.Send(); } string signature(string secret, string json) { MD5 md5 = MD5.Create(); var contentMD5bytes = md5.ComputeHash(System.Text.Encoding.ASCII.GetBytes(json)); StringBuilder sb = new StringBuilder(); for (int i = 0; i < contentMD5bytes.Length; i++) { sb.Append(contentMD5bytes[i].ToString("x2")); } string contentMD5 = sb.ToString(); string StringToSign = string.Format("{0}\n{1}\n{2}\n{3}\n{4}", "POST", contentMD5, "application/json", Date, "/targets"); HMACSHA1 sha1 = new HMACSHA1(System.Text.Encoding.ASCII.GetBytes(secret), true); //HMACSHA1 sha1 = new HMACSHA1(System.Text.Encoding.ASCII.GetBytes(secret)); byte[] sha1Bytes = Encoding.ASCII.GetBytes(StringToSign); MemoryStream stream = new MemoryStream(sha1Bytes); byte[] sha1Hash = sha1.ComputeHash(stream); string signature = System.Convert.ToBase64String(sha1Hash); return signature; } }