send post Https request with Content Type application Json on C#

Question

I'm trying to send the following request:

 POST /messaging/registrations/(REGISTRATION_ID_FOR_DESTINATION_APP_INSTANCE)/messages   HTTP/1.1
 Host: api.amazon.com
 Authorization: Bearer (MY_ACCESS_TOKEN)
 Content-Type: application/json
 X-Amzn-Type-Version: [email protected]
 Accept: application/json
 X-Amzn-Accept-Type: [email protected]
 
 {
"data":{"message":"value1","title":"value2"},
"consolidationKey":"Some Key",
"expiresAfter":86400
 }

in order to get a response format like this:

 HTTP/1.1 200
 X-Amzn-Data-md5: t5psxALRTM7WN30Q8f20tw==
 X-Amzn-RequestId: e8bef3ce-242e-11e2-8484-47f4656fc00d
 Content-Type: application/json
 X-Amzn-Type-Version: [email protected]
 Content-Length: 308
  
 {"registrationID":(REGISTRATION_ID_FOR_DESTINATION_APP_INSTANCE)}

to do that I tried with this code:

private void sendNotification(String registrationID,String message,
                                          String title,String accessToken)
{     
 //registrationID content (REGISTRATION_ID_FOR_DESTINATION_APP_INSTANCE) that can vary
 string url = "https://api.amazon.com/messaging/registrations/"+ registrationID +"/messages";

 var client = new HttpClient();

 //set Request headers 
 client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue(
                                                      "Bearer", accessToken);
 client.DefaultRequestHeaders.Accept.Add(
             new MediaTypeWithQualityHeaderValue("application/json"));
 client.DefaultRequestHeaders.Add("X-Amzn-Type-Version",
                                "[email protected]");
 client.DefaultRequestHeaders.Add("X-Amzn-Accept-Type",
                            "[email protected]");

 //the content of the message body

 var content = new Dictionary<string, Object>();
 content.Add("consolidationKey", "SyncNow");
 content.Add("expiresAfter", 86400);
 var data = new Dictionary<string, string>();
 data.Add("message", message);
 data.Add("title", title);
 content.Add("data", data);

       
 var result = client.PostAsJsonAsync<Dictionary<string, Object>>(url, content).Result;
}

As response I get StatusCode:400,ReasonPhrase:'Bad Request', I don't know why?

For detail about result which I got:

  result    {StatusCode: 400, ReasonPhrase: 'Bad Request', Version: 1.1, Content: System.Net.Http.StreamContent, Headers:
 {
  x-amzn-RequestId: 1b943a1c-fe94-11e2-b963-71a537223b43
  Vary: Accept-Encoding
  Vary: User-Agent
  Cneonction: close
  Date: Tue, 06 Aug 2013 12:31:24 GMT
  Content-Length: 34
  Content-Type: application/json
 }}    System.Net.Http.HttpResponseMessage

 result.RequestMessage  {Method: POST, 
 RequestUri: 'https://api.amazon.com/messaging/registrations/(REGISTRATION_ID_FOR_DESTINATION_APP_INSTANCE)/messages', 
 Version: 1.1, 
 Content: System.Net.Http.ObjectContent`1[[System.Collections.Generic.Dictionary`2[[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],
 [System.Object, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]], mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]], 
 Headers:
 {
  Authorization: Bearer (MY_ACCESS_TOKEN)
  Accept: application/json
  X-Amzn-Type-Version: [email protected]
  X-Amzn-Accept-Type: [email protected]
  Content-Type: application/json; charset=utf-8
  Content-Length: 98
 }}       System.Net.Http.HttpRequestMessage

Answer 1

I found an other solution that work perfectly .

private void sendNotification(String registrationID,String message,String title,String accessToken)
    {
       HttpWebRequest httpWReq =
            (HttpWebRequest)WebRequest.Create("https://api.amazon.com/messaging/registrations/" + registrationID + "/messages");

        Encoding encoding = new UTF8Encoding();
        string postData = "{\"data\":{\"message\":\""+message+"\",\"title\":\""+title+"\"},\"consolidationKey\":\"Some Key\",\"expiresAfter\":86400}";
        byte[] data = encoding.GetBytes(postData);

        httpWReq.ProtocolVersion = HttpVersion.Version11;
        httpWReq.Method = "POST";
        httpWReq.ContentType = "application/json";//charset=UTF-8";
        httpWReq.Headers.Add("X-Amzn-Type-Version",
                                           "[email protected]");
        httpWReq.Headers.Add("X-Amzn-Accept-Type",
                                        "[email protected]");
        httpWReq.Headers.Add(HttpRequestHeader.Authorization,
            "Bearer " + accessToken);
        httpWReq.ContentLength = data.Length;


        Stream stream = httpWReq.GetRequestStream();
        stream.Write(data, 0, data.Length);
        stream.Close();

        HttpWebResponse response = (HttpWebResponse)httpWReq.GetResponse();
        string s=response.ToString();
        StreamReader reader = new StreamReader(response.GetResponseStream());
        String jsonresponse = "";
        String temp = null;
        while ((temp = reader.ReadLine()) != null)
        {
            jsonresponse += temp;
        }

    }