Push Notification From C# .Net to Android Using FCM HTTP V1

Section 9. Use the Authorization token generated above via c# code to call FCM HTTP V1 API; get the FCM Token of Android from an Android device. Test using Postman; a push notification will be sent to the Android device.

Section 10. On successful completion of the above steps, Implement Further, Create this Model Classes for storing Request & Response data.

Section 11. Call the FCM HTTP V1 API using the Authorization token generated & get the FCM id / Token from the Android device.

Section 12. Entire Code

#region FCM Auth & Send Notification To Mobile //notify FCM Code

public class Data {

  public string body {
    get;
    set;
  }

  public string title {
    get;
    set;
  }

  public string key_1 {
    get;
    set;
  }

  public string key_2 {
    get;
    set;
  }

}

public class Message {

  public string token {
    get;
    set;
  }

  public Data data {
    get;
    set;
  }

  public Notification notification {
    get;
    set;
  }

}

public class Notification {

  public string title {
    get;
    set;
  }

  public string body {
    get;
    set;
  }

}

public class Root {

  public Message message {
    get;
    set;
  }

}

public void GenerateFCM_Auth_SendNotifcn()

{
  //----------Generating Bearer token for FCM---------------

  string fileName = System.Web.Hosting.HostingEnvironment.MapPath("~/***-approval-firebase-adminsdk-gui00-761039f087.json"); //Download from Firebase Console ServiceAccount

  string scopes = "https://www.googleapis.com/auth/firebase.messaging";
  var bearertoken = ""; // Bearer Token in this variable
  using(var stream = new FileStream(fileName, FileMode.Open, FileAccess.Read))

  {

    bearertoken = GoogleCredential
      .FromStream(stream) // Loads key file
      .CreateScoped(scopes) // Gathers scopes requested
      .UnderlyingCredential // Gets the credentials
      .GetAccessTokenForRequestAsync().Result; // Gets the Access Token

  }

  ///--------Calling FCM-----------------------------

  var clientHandler = new HttpClientHandler();
  var client = new HttpClient(clientHandler);

  client.BaseAddress = new Uri("https://fcm.googleapis.com/v1/projects/***-approval/messages:send"); // FCM HttpV1 API

  client.DefaultRequestHeaders.Accept.Clear();
  client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

  //client.DefaultRequestHeaders.Accept.Add("Authorization", "Bearer " + bearertoken);
  client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", bearertoken); // Authorization Token in this variable

  //---------------Assigning Of data To Model --------------

  Root rootObj = new Root();
  rootObj.message = new Message();

  rootObj.message.token = "cEM68BIdTomaE0R2dbaO:APA91bG8XfOjU_GSPNQYCrJ4wzE7VmMPEsyudwtE41VWKzJcoT2f3wbKsKCHwk5s078ZL31mM258-BzdZPRNXAlc_fyzCzj2txLQvQ3u7jggDPHjYIMlHRgspXT0CudfK"; //FCM Token id

  rootObj.message.data = new Data();
  rootObj.message.data.title = "Data Title";
  rootObj.message.data.body = "Data Body";
  rootObj.message.data.key_1 = "Sample Key";
  rootObj.message.data.key_2 = "Sample Key2";
  rootObj.message.notification = new Notification();
  rootObj.message.notification.title = "Notify Title";
  rootObj.message.notification.body = "Notify Body";

  //-------------Convert Model To JSON ----------------------

  var jsonObj = new JavaScriptSerializer().Serialize(rootObj);

  //------------------------Calling Of FCM Notify API-------------------

  var data = new StringContent(jsonObj, Encoding.UTF8, "application/json");
  data.Headers.ContentType = new MediaTypeHeaderValue("application/json");

  var response = client.PostAsync("https://fcm.googleapis.com/v1/projects/**-approval/messages:send", data).Result; // Calling The FCM httpv1 API

  //---------- Deserialize Json Response from API ----------------------------------

  var jsonResponse = response.Content.ReadAsStringAsync().Result;
  var responseObj = new JavaScriptSerializer().DeserializeObject(jsonResponse);

}

#endregion