How to implement apple token based push notifications (using p8 file) in C#?

Question

For an app with some kind of chat based features I want to add push notification support for receiving new messages. What I want to do is use the new token based authenticat

Answer 1

It have tried the above on ASP.NET CORE 2.1 and 2.2 to no avail. The response I always got was "The message received was unexpected or badly formatted" with HttpVersion20 enabled, which made me doubt whether http2 implementation is concrete.

Below is what worked on ASP.NET CORE 3.0;

 var teamId = "YOURTEAMID";
 var keyId = "YOURKEYID";

            try
            {
                //
                var data = await System.IO.File.ReadAllTextAsync(Path.Combine(_environment.ContentRootPath, "apns/"+config.P8FileName));
                var list = data.Split('\n').ToList();
                var prk = list.Where((s, i) => i != 0 && i != list.Count - 1).Aggregate((agg, s) => agg + s);
                //
                var key = new ECDsaCng(CngKey.Import(Convert.FromBase64String(prk), CngKeyBlobFormat.Pkcs8PrivateBlob));
                //
                var token = CreateToken(key, keyId, teamId);
                //
                var deviceToken = "XXXXXXXXXXXXXXXXXXXXXXXXXXXX";
                var url = string.Format("https://api.sandbox.push.apple.com/3/device/{0}", deviceToken);
                var request = new HttpRequestMessage(HttpMethod.Post, url);
                //
                request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);
                //

                request.Headers.TryAddWithoutValidation("apns-push-type", "alert"); // or background
                request.Headers.TryAddWithoutValidation("apns-id", Guid.NewGuid().ToString("D"));
                //Expiry
                //
                request.Headers.TryAddWithoutValidation("apns-expiration", Convert.ToString(0));
                //Send imediately
                request.Headers.TryAddWithoutValidation("apns-priority", Convert.ToString(10));
                //App Bundle
                request.Headers.TryAddWithoutValidation("apns-topic", "com.xx.yy");
                //Category
                request.Headers.TryAddWithoutValidation("apns-collapse-id", "test");

                //
                var body = JsonConvert.SerializeObject(new
                {
                    aps = new
                    {
                        alert = new
                        {
                            title = "Test",
                            body = "Sample Test APNS",
                            time = DateTime.Now.ToString()
                        },
                        badge = 1,
                        sound = "default"
                    },
                    acme2 = new string[] { "bang", "whiz" }
                })
                //
                request.Version = HttpVersion.Version20;
                //
                using (var stringContent = new StringContent(body, Encoding.UTF8, "application/json"))
                {
                    //Set Body
                    request.Content = stringContent;
                    _logger.LogInformation(request.ToString());
                    //
                    var handler = new HttpClientHandler();
                    //
                    handler.SslProtocols = SslProtocols.Tls12 | SslProtocols.Tls11 | SslProtocols.Tls;
                    //
                    handler.ServerCertificateCustomValidationCallback = (message, cert, chain, errors) => true;

                    //Continue
                    using (HttpClient client = new HttpClient(handler))
                    {
                        //
                        HttpResponseMessage resp = await client.SendAsync(request).ContinueWith(responseTask =>
                        {
                            return responseTask.Result;
                            //

                        });
                        //
                        _logger.LogInformation(resp.ToString());
                        //
                        if (resp != null)
                        {
                            string apnsResponseString = await resp.Content.ReadAsStringAsync();
                            //
                            handler.Dispose();
                            //ALL GOOD ....
                            return;
                        }
                        //
                        handler.Dispose();
                    }
                }
            }
            catch (HttpRequestException e)
            {
                _logger.LogError(5, e.StackTrace, e);
            }

For CreateToken() Refer Above Recommended solution by yaakov,