发送来自服务器的GCM消息（下游HTTP JSON）

Question

您能否通过下载HTTP JSON提供简单的代码（或链接），以便从我的C＃服务器向Android设备发送简单消息？

我使用下一个简单的c＃代码来发送消息使用下游HTTP纯文本。但我需要与JSON这样做，因为我需要使用优先级字段。

private string SendMessageUsingGCM(String sRegistrationId, string sTextToSend, string sCollapseKey) 
{ 
    String GCM_URL = @"https://gcm-http.googleapis.com/gcm/send"; 
    bool flag = false; 
    string sError = ""; 

    StringBuilder sb = new StringBuilder(); 
    sb.AppendFormat("registration_id={0}&collapse_key={1}", sRegistrationId, sCollapseKey); 
    sb.AppendFormat("&delay_while_idle=0&priority=high"); //priority field will not work on this kind of messages 
    sb.AppendFormat("&data.msg=" + HttpUtility.UrlEncode(sTextToSend)); //To send special characters like ä, ë, arabs... 
    string msg = sb.ToString(); 

    HttpWebRequest req = (HttpWebRequest)WebRequest.Create(GCM_URL); 
    req.Method = "POST"; 
    req.ContentLength = msg.Length; 
    req.ContentType = "application/x-www-form-urlencoded"; 
    req.Timeout = 20000; 

    req.Headers.Add("Authorization:key=" + MyAthorizationKey); 

    try 
    { 
     using (StreamWriter oWriter = new StreamWriter(req.GetRequestStream())) 
     { 
      oWriter.Write(msg); 
     } 

     using (HttpWebResponse resp = (HttpWebResponse)req.GetResponse()) 
     { 
      using (StreamReader sr = new StreamReader(resp.GetResponseStream())) 
      { 
       string respData = sr.ReadToEnd(); 

       if (resp.StatusCode == HttpStatusCode.OK) // OK = 200 
       { 
        if (respData.StartsWith("id=")) 
         flag = true; 
        else 
         sError = respData; 
       } 
       else if (resp.StatusCode == HttpStatusCode.InternalServerError) // 500 
        sError = "Internal server error. Try later."; 
       else if (resp.StatusCode == HttpStatusCode.ServiceUnavailable) // 503 
        sError = "Server not available temnporatily. Try later."; 
       else if (resp.StatusCode == HttpStatusCode.Unauthorized)   // 401 
        sError = "The API Key is not valid."; 
       else 
        sError = "Error: " + resp.StatusCode; 
      } 
     } 
    } 
    catch (WebException e) 
    { //The remote server returned an error: (502) Bad Gateway. //Más info: http://stackoverflow.com/questions/2159361/error-502-bad-gateway-when-sending-a-request-with-httpwebrequest-over-ssl 
     //The remote server returned an error: (500) Internal Server Error. Más info: http://stackoverflow.com/questions/4098945/500-internal-server-error-at-getresponse 
     sError = "WebException: " + e.ToString(); 
    } 
    catch (Exception e) 
    { 
     sError = "Exception: " + e.ToString(); 
    } 


    if (flag == true) 
     return "Ok"; 

    return "Error " + sError; 
} 

Answer 1

private string SendMessageUsingGCM(String sRegistrationId, string sTextToSend, string sCollapseKey) 
{ 
    String GCM_URL = @"https://gcm-http.googleapis.com/gcm/send"; 
    bool flag = false; 
    string sError = ""; 

    string msg = "{"; 
    msg += "\"to\": \"" + sRegistrationId+ "\","; 
    msg += "\"collapse_key\": \"" + sCollapseKey + "\", "; 
    msg += "\"priority\": \"high\","; 
    msg += "\"data\": {\"msg\": \"" + sTextToSend+ "\" }"; 
    msg += "}"; 

    HttpWebRequest req = (HttpWebRequest)WebRequest.Create(GCM_URL); 
    req.Method = "POST"; 
    req.ContentLength = msg.Length; 
    req.ContentType = "application/json"; 
    req.Timeout = 2000; 
    req.Headers.Add("Authorization:key=" + MyAthorizationKey); 

    try 
    { 
     Byte[] byteArray = Encoding.UTF8.GetBytes(msg); 
     req.ContentLength = byteArray.Length; //<--To send special characters like ä, ë, arabs... http://stackoverflow.com/questions/32537219/error-httpwebrequest-bytes-to-be-written-to-the-stream-exceed-the-content-len 
     Stream writer = req.GetRequestStream(); 
     writer.Write(byteArray, 0, byteArray.Length); 

     using (HttpWebResponse resp = (HttpWebResponse)req.GetResponse()) 
     { 
      using (StreamReader sr = new StreamReader(resp.GetResponseStream())) 
      { 
       string respData = sr.ReadToEnd(); 

       if (resp.StatusCode == HttpStatusCode.OK) // OK = 200 
       { 
        if (respData.StartsWith("id=")) 
         flag = true; 
        else 
         sError = respData; 
       } 
       else if (resp.StatusCode == HttpStatusCode.InternalServerError) // 500 
        sError = "Internal server error. Try later."; 
       else if (resp.StatusCode == HttpStatusCode.ServiceUnavailable) // 503 
        sError = "Server not available temnporatily. Try later."; 
       else if (resp.StatusCode == HttpStatusCode.Unauthorized)   // 401 
        sError = "The API Key is not valid."; 
       else 
        sError = "Error: " + resp.StatusCode; 
      } 
     } 
    } 
    catch (WebException e) 
    { //The remote server returned an error: (502) Bad Gateway. //Más info: http://stackoverflow.com/questions/2159361/error-502-bad-gateway-when-sending-a-request-with-httpwebrequest-over-ssl 
     //The remote server returned an error: (500) Internal Server Error. Más info: http://stackoverflow.com/questions/4098945/500-internal-server-error-at-getresponse 
     sError = "WebException: " + e.ToString(); 
    } 
    catch (Exception e) 
    { 
     sError = "Exception: " + e.ToString(); 
    } 


    if (flag == true) 
     return "Ok"; 

    return "Error " + sError; 
}