android - c2dm server with C#

Question

Do anyone know if its possible to create a c2dm serverside with C#? How do i add the required parameters (email, password etc)?

Answer 1

Here is the core of a basic prototype C# server I created.

class C2DMPrototype
{
    // Hardcoded for now
    private const string RegistrationId = "XXXXXXXXXXX";

    private const string GoogleAuthUrl = "https://www.google.com/accounts/ClientLogin";
    // TODO : Production code should use https (secure) push and have the correct certificate
    private const string GoogleMessageUrl = "http://android.clients.google.com/c2dm/send";

    private const string PostWebRequest = "POST";
    private const string AuthTokenHeader = "Auth=";
    private const string UpdateClientAuth = "Update-Client-Auth";

    // Post data parameters
    private const string RegistrationIdParam = "registration_id";
    private const string CollapseKeyParam = "collapse_key";
    private const string DataPayloadParam = "data.payload";
    private const string DelayWhileIdleParam = "delay_while_idle";

    private string _authTokenString = String.Empty;
    private string _updatedAuthTokenString = String.Empty;
    private string _message = String.Empty;

    public void StartServer()
    {
        if ((_authTokenString = GetAuthentificationToken()).Equals(String.Empty))
        {
            Console.ReadLine();
            return;
        }

        while (true)
        {
            try
            {
                Console.Write("Message> ");
                _message = Console.ReadLine().ToLower().Trim();
                SendMessage(_authTokenString, RegistrationId, _message);
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
                Console.WriteLine(ex.StackTrace);
            }
        }
    }

    private static string GetAuthentificationToken()
    {
        string authTokenString = String.Empty;
        try
        {
            WebRequest request = WebRequest.Create(GoogleAuthUrl);
            request.Method = PostWebRequest;

            NameValueCollection postFieldNameValue = new NameValueCollection();
            postFieldNameValue.Add("Email", "XXXXXXXXXXX");
            postFieldNameValue.Add("Passwd", "XXXXXXXXXXX");
            postFieldNameValue.Add("accountType", "GOOGLE");
            postFieldNameValue.Add("source", "Google-cURL-Example");
            postFieldNameValue.Add("service", "ac2dm");

            string postData = GetPostStringFrom(postFieldNameValue);
            byte[] byteArray = Encoding.UTF8.GetBytes(postData);

            request.ContentType = "application/x-www-form-urlencoded";
            request.ContentLength = byteArray.Length;

            Stream dataStream = request.GetRequestStream();
            dataStream.Write(byteArray, 0, byteArray.Length);
            dataStream.Close();

            WebResponse response = request.GetResponse();
            if (((HttpWebResponse)response).StatusCode.Equals(HttpStatusCode.OK))
            {
                dataStream = response.GetResponseStream();
                StreamReader reader = new StreamReader(dataStream);

                string responseFromServer = reader.ReadToEnd();

                authTokenString = ParseForAuthTokenKey(responseFromServer);

                reader.Close();
                dataStream.Close();
            }
            else
            {
                Console.WriteLine("Response from web service not OK :");
                Console.WriteLine(((HttpWebResponse)response).StatusDescription);
            }

            response.Close();
        }
        catch (Exception ex)
        {
            Console.WriteLine("Getting Authentication Failure");
            Console.WriteLine(ex.Message);
        }
        return authTokenString;
    }

    private static void SendMessage(string authTokenString, string registrationId, string message)
    {
        //Certeficate was not being accepted for the sercure call
        //ServicePointManager.ServerCertificateValidationCallback += new RemoteCertificateValidationCallback(ValidateServerCertificate);

        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(GoogleMessageUrl);
        request.Method = PostWebRequest;
        request.KeepAlive = false;

        NameValueCollection postFieldNameValue = new NameValueCollection();
        postFieldNameValue.Add(RegistrationIdParam, registrationId);
        postFieldNameValue.Add(CollapseKeyParam, "0");
        postFieldNameValue.Add(DelayWhileIdleParam, "0");
        postFieldNameValue.Add(DataPayloadParam, message);

        string postData = GetPostStringFrom(postFieldNameValue);
        byte[] byteArray = Encoding.UTF8.GetBytes(postData);

        request.ContentType = "application/x-www-form-urlencoded;charset=UTF-8";
        request.ContentLength = byteArray.Length;

        request.Headers.Add(HttpRequestHeader.Authorization, "GoogleLogin auth=" + authTokenString);

        Stream dataStream = request.GetRequestStream();
        dataStream.Write(byteArray, 0, byteArray.Length);
        dataStream.Close();

        WebResponse response = request.GetResponse();
        HttpStatusCode responseCode = ((HttpWebResponse)response).StatusCode;
        if (responseCode.Equals(HttpStatusCode.Unauthorized) || responseCode.Equals(HttpStatusCode.Forbidden))
        {
            Console.WriteLine("Unauthorized - need new token");
        }
        else if (!responseCode.Equals(HttpStatusCode.OK))
        {
            Console.WriteLine("Response from web service not OK :");
            Console.WriteLine(((HttpWebResponse)response).StatusDescription);
        }

        StreamReader reader = new StreamReader(response.GetResponseStream());
        string responseLine = reader.ReadLine();
        reader.Close();
    }

    private static string GetPostStringFrom(NameValueCollection nameValuePair)
    {
        StringBuilder postString = new StringBuilder();
        for (int i = 0; i < nameValuePair.Count; i++)
        {
            postString.Append(nameValuePair.GetKey(i));
            postString.Append("=");
            postString.Append(Uri.EscapeDataString(nameValuePair[i]));
            if (i + 1 != nameValuePair.Count)
            {
                postString.Append("&");
            }
        }
        return postString.ToString();
    }

    private static string ParseForAuthTokenKey(string webResponse)
    {
        string tokenKey = String.Empty;
        if (webResponse.Contains(AuthTokenHeader))
        {
            tokenKey = webResponse.Substring(webResponse.IndexOf(AuthTokenHeader) + AuthTokenHeader.Length);
            if (tokenKey.Contains(Environment.NewLine))
            {
                tokenKey.Substring(0, tokenKey.IndexOf(Environment.NewLine));
            }
        }
        return tokenKey.Trim();
    }

    public static bool ValidateServerCertificate(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
    {
        // Return "true" to force the certificate to be accepted.
        return true;
    }
}