Index

• Introduction
• The Android Application
• Sending from Firebase Portal
• The .Net Core Service

Code on Github

Console Application

• Create a new .Net Core empty application and add the Newtonosoft.Json package

• Then we define the data types for the message. Notice the JsonProperty to adapt the FCM style of Json data

    public class NotificationData
    {
        public string ShortDesc { get; set; }
        public long IncidentNo { get; set; }
        public string Description { get; set; }
    }
  
    public class Notification
    {
        public Notification()
        {
            Sound = "default";
        }
  
        [JsonProperty("title")]
        public string Title { get; set; }
  
        [JsonProperty("text")]
        public string Text { get; set; }
  
        [JsonProperty("sound")]
        public string Sound { get; set; }
    }
  
    public class NotificationMessage
    {
        [JsonProperty("to")]
        public string To { get; set; }
  
        [JsonProperty("data")]
        public NotificationData Data { get; set; }
  
        [JsonProperty("notification")]
        public Notification Notification { get; set; }
    }
  

• Then fill the main. The Server key is the one founded inside the FCM console, Settings->Cloud Messaging->Server key

    class Program
    {
        static void Main(string[] args)
        {
            SendNotificationFromFirebaseCloud();
        }
  
        public static String SendNotificationFromFirebaseCloud()
        {
            var result = "-1";
            var webAddr = "https://fcm.googleapis.com/fcm/send";
            var httpWebRequest = (HttpWebRequest)WebRequest.Create(webAddr);
            httpWebRequest.ContentType = "application/json";
            httpWebRequest.Headers.Add(HttpRequestHeader.Authorization, "key=PROJECTSETTINGS->Cloud Messagings->Server Key");
            httpWebRequest.Method = "POST";
            using (var streamWriter = new StreamWriter(httpWebRequest.GetRequestStream()))
            {
                string strNJson = JsonConvert.SerializeObject(new NotificationMessage
                {
                    To = "/topics/ServiceNow",
                    Data = new NotificationData
                    {
                        Description = "Detailed description",
                        IncidentNo = 12345,
                        ShortDesc = "Short desc."
                    },
                    Notification = new Notification
                    {
                        Title = "ServiceNow: Incident No." + 12345,
                        Text = "This is Notification"
                    }
                });
                streamWriter.Write(strNJson);
                streamWriter.Flush();
            }
  
            var httpResponse = (HttpWebResponse)httpWebRequest.GetResponse();
            using (var streamReader = new StreamReader(httpResponse.GetResponseStream()))
            {
                result = streamReader.ReadToEnd();
            }
            return result;
        }
    }
  

• Just run and...surprise :) It works!

Adding the API

• Add the following nuget packages:

  • Microsoft.AspNetCore
  • Microsoft.AspNetCore.Hosting
  • Microsoft.AspNetCore.Mvc

• Now should add the "Web" stuff. The WebStartup class is used to start a web application

    public class WebStartup
    {
        public IConfiguration Configuration { get; }
        public WebStartup(IConfiguration configuration)
        {
            Configuration = configuration;
        }
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddMvc();
        }
        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
  
            app.UseMvc();
  
        }
    }
  

• Now change the main to start the application...and quit when needed

    class Program
    {
        static void Main(string[] args)
        {
            var host = WebHost
                .CreateDefaultBuilder()
                .UseKestrel()
                .UseStartup<WebStartup>()
                .UseUrls("http://*:5006")
                .Build();
            host.Start();
  
            while (true)
            {
                if ("quit" == Console.ReadLine())
                {
                    break;
                }
            }
        }
    }
  

• Time then to add the models for our project

    public class NotificationModel
    {
        public string ShortDesc { get; set; }
        public long IncidentNo { get; set; }
        public string Description { get; set; }
    }
  
    public class NotificationResult
    {
        public string Result { get; internal set; }
    }
  

• And let's add a Controller

    [Produces("application/json")]
    [Route("api/notifications")]
    public class NotificationsController : Controller
    {
        [HttpPost]
        [Route("")]
        public NotificationResult Send(NotificationModel messageData)
        {
            var result = "-1";
            var webAddr = "https://fcm.googleapis.com/fcm/send";
            var httpWebRequest = (HttpWebRequest)WebRequest.Create(webAddr);
            httpWebRequest.ContentType = "application/json";
            httpWebRequest.Headers.Add(HttpRequestHeader.Authorization, "key=PROJECTSETTINGS->Cloud Messagings->Server Key");
            httpWebRequest.Method = "POST";
            using (var streamWriter = new StreamWriter(httpWebRequest.GetRequestStream()))
            {
                string strNJson = JsonConvert.SerializeObject(new NotificationMessage
                {
                    To = "/topics/ServiceNow",
                    Data = new NotificationData
                    {
                        Description = messageData.Description,
                        IncidentNo = messageData.IncidentNo,
                        ShortDesc = messageData.ShortDesc
                    },
                    Notification = new Notification
                    {
                        Title = "ServiceNow: Incident No." + messageData.IncidentNo,
                        Text = "Notification"
                    }
                });
                streamWriter.Write(strNJson);
                streamWriter.Flush();
            }
  
            var httpResponse = (HttpWebResponse)httpWebRequest.GetResponse();
            using (var streamReader = new StreamReader(httpResponse.GetResponseStream()))
            {
                result = streamReader.ReadToEnd();
            }
  
            return new NotificationResult
            {
                Result = result
            };
        }
        [HttpGet]
        [Route("sanity")]
        public string Sanity()
        {
            return "OK";
        }
    }
  

• Now with a simple curl (download here curl for windows) you can send notifications to the phone!

    curl --header "Content-Type: application/json" --request POST --data '{"IncidentNo":122,"ShortDesc":"Short incident","Description":"Long description"}' http://localhost:5006/api/notifications