In this article I will try to explain how we can integrate a push notification service for Android using ASP.NET and C#. We all know that mobile applications are booming the market trend.
Some custom mobile applications use the push notification service to give updates to application users. Here I will explain how we can use Google’s C2DM (Cloud to Device Messaging)
push notification service. The figure above shows a typical flow of push notification.
- Components — The physical entities that play a role in C2DM.
- Credentials — The IDs and tokens that are used in different stages of C2DM to ensure that all parties have been authenticated, and that the message is going to the correct place.
|Mobile Device||The device that is running an Android application that uses C2DM. This must be a 2.2 Android device that has Market installed, and it must have at least one
logged-in Google account.|
|Third Party Application Server||An application server that developers set up as part of implementing C2DM in their applications. The third-party application server sends data to an
Android application on the device via the C2DM server.|
|C2DM Server||The Google servers involved in taking messages from the third-party application server and sending them to the device.|
|Sender ID||An email account associated with the application's developer. The sender ID is used in the registration process to identify an Android application that is
permitted to send messages to the device. This ID is typically role-based rather than being a personal account—- for example, firstname.lastname@example.org.|
|Application ID||The application that is registering to receive messages. The application is identified by the package name from the manifest. This ensures that the
messages are targeted at the correct application.|
|Registration ID||An ID issued by C2DM servers to the Android application that allows it to receive messages. Once the application has the registration ID, it sends it
to the third-party application server, which uses it to identify each device that has registered to receive messages for a given application. In other words,
a registration ID is tied to a particular application running on a particular device.|
|Google User Account||For C2DM to work, the mobile device must include at least one logged-in Google account.|
|Sender Auth Token||A ClientLogin Auth token that is saved on the third-party application server that gives the application server authorized access to Google services.
The token is included in the header of POST requests that sends messages. For more discussion of ClientLogin Auth tokens, see ClientLogin for Installed Applications.|
Life Cycle Flow
Here are the primary processes involved in cloud-to-device messaging:
- Enabling C2DM - An Android application running on a mobile device registers to receive messages.
- Sending a message - A third-party application server sends messages to the device.
- Receiving a message - An Android application receives a message from a C2DM server.
Action Item From Android Application
- First you need to register your application with C2DM services. http://code.google.com/android/c2dm/signup.html
- Integrate C2DM to the Android application and Google will return the RegistrationID. Use this RegistrationID in the ASP.NET application.
Action Item From ASP.NET Application
On the ASP.NET application side, we require the following credentials:
- Google User Account
- Message Text
Your code should follow the three simple steps below to send a Push notification.
- Authentication process with Google.
- Server certification validation.
- Submit a message.
Let’s go one by one.
1. Authentication Process
First you need to pass the SenderID (Google user account name) and its password to get the authentication string. Remember, this authentication string will be used
when we submit message to the C2DM server.
public string CheckAuthentication(string SenderID, string Password)
string Array = "";
string URL = "https://www.google.com/accounts/ClientLogin?";
string fullURL = URL + "Email=" + SenderID.Trim() + "&Passwd=" + Password.Trim() +
"&accountType=GOOGLE" + "&source=Company-App-Version" + "&service=ac2dm";
HttpWebRequest Request = (HttpWebRequest)HttpWebRequest.Create(fullURL);
HttpWebResponse Response = (HttpWebResponse)Request.GetResponse();
int Index = 0;
if (Response.StatusCode == HttpStatusCode.OK)
Stream Stream = Response.GetResponseStream();
Reader = new StreamReader(Stream);
string File = Reader.ReadToEnd();
Index = File.ToString().IndexOf("Auth=") + 5;
int len = File.Length - Index;
Array = File.ToString().Substring(Index, len);
catch (Exception ex)
Array = ex.Message;
ex = null;
2. Server Certification
Here we are not going to install any certificates on the development workstation or application server and then verify it in code.
But we are doing a little bit of delegation modeling for the validating server certification.
Make sure this delegation method is called before we submit a message to C2DM.
ServicePointManager.ServerCertificateValidationCallback += delegate(
3. Send Message
Finally we are in the last step to send the push notification on the device. After successfully finishing
the above two steps we have to write the below code to finalize the process.
Now we have to use RegistrationID, Message, and AuthenticationToken/String here.
First create a
httpWebRequest object with the URL that is shown in the code. Also we need to pass the following name value pair as a query string along with the URL.
registration_id<br />collapse_key<br />delay_while_idle<br />data.payload
(In case you can use
data.message as an alternate.)
Read the below code and try to understand the implementation.
public string SendMessage(string RegistrationID, string Message, string AuthString)
HttpWebRequest Request = (HttpWebRequest)WebRequest.Create(
Request.Method = "POST";
Request.KeepAlive = false;
NameValueCollection postFieldNameValue = new NameValueCollection();
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=" + AuthString);
ServicePointManager.ServerCertificateValidationCallback += delegate(
Stream dataStream = Request.GetRequestStream();
dataStream.Write(byteArray, 0, byteArray.Length);
WebResponse Response = Request.GetResponse();
HttpStatusCode ResponseCode = ((HttpWebResponse)Response).StatusCode;
if (ResponseCode.Equals(HttpStatusCode.Unauthorized) ||
return "Unauthorized - need new token";
else if (!ResponseCode.Equals(HttpStatusCode.OK))
return "Response from web service isn't OK";
StreamReader Reader = new StreamReader(Response.GetResponseStream());
string responseLine = Reader.ReadLine();
Using the Code Sample
You can browse the attached sample code. I have created it as a library file. You can add AndroidPushNotification.dll to your project reference and use it.
To send a push notification to the Android application is now just two lines of code.
public partial class Default : System.Web.UI.Page
protected void Page_Load(object sender, EventArgs e)
PushNotification.PushNotification objPush =
blStatus.Text = objPush.Android("5grDMrPboQIz0Fpyojo-_u2",
"email@example.com", "myapppassword", "Testing DLL");
objPush.Android function with
I hope this code will make your life easy to integrate the Android Push Notification with ASP.NET
and C#. Again reminding you that you can use this code to run an Android push notification without any server certification.