add dke:ping (#138)

* add dke:ping

* fix mistake

* cleanup

* Remove unused test output helper from PingServiceTest

The test output helper was not being utilized in the PingServiceTest class and has been removed to clean up the code. Additionally, a minor spacing adjustment was made in the existing Fact attribute for consistency.

* Refactor variable declaration in PingServiceTest

Simplify variable declaration from explicit type to 'var' in PingServiceTest. This change promotes readability and adheres to modern C# coding conventions.

* Update skip reason for PingServiceTest

Clarify the reason for skipping the PingServiceTest fact. The updated message highlights that a deleted endpoint cannot be automatically tested and requires manual actions.

* Refactor test method for deleted endpoint handling

Updated PingServiceTest.cs to refactor a test method for better readability. Changed variable declaration and initialization style for consistency. Kept skip attribute message format consistent across tests.

* Simplify imports in PingServiceTest.cs

Removed unused using directives in PingServiceTest.cs to clean up the code. This helps improve readability and maintainability by excluding unnecessary dependencies.

* Remove unused import in PingService.cs

Eliminated an unnecessary import statement for `Agrirouter.Feed.Request` in PingService.cs to clean up the code. This change helps in maintaining clarity and avoiding potential confusion with unused references.

---------

Co-authored-by: Sascha Doemer <[email protected]>

agrirouter-sdk-dotnet-standard-api/Definitions/TechnicalMessageTypeDefinitions.cs

@@ -52,6 +52,11 @@ public static class TechnicalMessageTypes
         /// </summary>
         public static string DkeSubscription => "dke:subscription";
 
+        /// <summary>
+        ///     Type 'dke:ping'.
+        /// </summary>
+        public static string DkePing => "dke:ping";
+
         /// <summary>
         ///     Type 'dke:cloud_onboard_endpoints'.
         /// </summary>

agrirouter-sdk-dotnet-standard-api/Service/Messaging/IPingService.cs

@@ -0,0 +1,11 @@
+using Agrirouter.Api.Service.Parameters;
+
+namespace Agrirouter.Api.Service.Messaging
+{
+    /// <summary>
+    ///     Send a ping message to check if the endpoint still exists.
+    /// </summary>
+    public interface IPingService : IMessagingService<PingParameters>, IEncodeMessageService<PingParameters>
+    {
+    }
+}

agrirouter-sdk-dotnet-standard-api/Service/Parameters/PingParameters.cs

@@ -0,0 +1,7 @@
+namespace Agrirouter.Api.Service.Parameters
+{
+    public class PingParameters : MessageParameters
+    {
+        // no additional fields, but more verbosity with explicit class definition
+    }
+}

agrirouter-sdk-dotnet-standard-impl/Service/Messaging/PingService.cs

@@ -0,0 +1,84 @@
+using System;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using Agrirouter.Api.Definitions;
+using Agrirouter.Api.Dto.Messaging;
+using Agrirouter.Api.Service.Messaging;
+using Agrirouter.Api.Service.Parameters;
+using Agrirouter.Impl.Service.Common;
+using Agrirouter.Request;
+using Google.Protobuf;
+
+namespace Agrirouter.Impl.Service.Messaging
+{
+    /// <summary>
+    ///     Service to list the endpoints connected to an endpoint.
+    /// </summary>
+    public class PingService: IPingService
+    {
+        private readonly IMessagingService<MessagingParameters> _messagingService;
+
+        /// <summary>
+        ///     Constructor.
+        /// </summary>
+        /// <param name="messagingService"></param>
+        public PingService(IMessagingService<MessagingParameters> messagingService)
+        {
+            _messagingService = messagingService;
+        }
+
+        /// <summary>
+        ///     Please see base class declaration for documentation.
+        /// </summary>
+        /// <param name="pingParameters">-</param>
+        /// <returns>-</returns>
+        public MessagingResult Send(PingParameters pingParameters)
+        {
+            var encodedMessages = new List<string> {Encode(pingParameters).Content};
+            var messagingParameters = pingParameters.BuildMessagingParameter(encodedMessages);
+            return _messagingService.Send(messagingParameters);
+        }
+
+        /// <summary>
+        ///     Please see base class declaration for documentation.
+        /// </summary>
+        /// <param name="pingParameters">-</param>
+        /// <returns>-</returns>
+        public Task<MessagingResult> SendAsync(PingParameters pingParameters)
+        {
+            var encodedMessages = new List<string> {Encode(pingParameters).Content};
+            var messagingParameters = pingParameters.BuildMessagingParameter(encodedMessages);
+            return _messagingService.SendAsync(messagingParameters);
+        }
+
+        /// <summary>
+        ///     Please see <seealso cref="IEncodeMessageService{T}.Encode" /> for documentation.
+        /// </summary>
+        /// <param name="pingParameters">-</param>
+        /// <returns>-</returns>
+        public EncodedMessage Encode(PingParameters pingParameters)
+        {
+            var messageHeaderParameters = new MessageHeaderParameters
+            {
+                ApplicationMessageId = pingParameters.ApplicationMessageId,
+                TeamSetContextId = pingParameters.TeamsetContextId ?? "",
+                TechnicalMessageType = TechnicalMessageTypes.DkePing,
+                Mode = RequestEnvelope.Types.Mode.Direct
+            };
+
+            var messagePayloadParameters = new MessagePayloadParameters
+            {
+                TypeUrl = "",
+                Value = ByteString.Empty
+            };
+
+            var encodedMessage = new EncodedMessage
+            {
+                Id = Guid.NewGuid().ToString(),
+                Content = EncodeMessageService.Encode(messageHeaderParameters, messagePayloadParameters)
+            };
+
+            return encodedMessage;
+        }
+    }
+}

agrirouter-sdk-dotnet-standard-test/Service/Messaging/Mqtt/PingServiceTest.cs

@@ -0,0 +1,114 @@
+using System;
+using System.Text;
+using System.Threading.Tasks;
+using Agrirouter.Api.Dto.Messaging;
+using Agrirouter.Api.Dto.Onboard;
+using Agrirouter.Api.Service.Parameters;
+using Agrirouter.Impl.Service.Common;
+using Agrirouter.Impl.Service.Messaging;
+using Agrirouter.Test.Data;
+using Agrirouter.Test.Helper;
+using MQTTnet;
+using MQTTnet.Client;
+using Newtonsoft.Json;
+using Xunit;
+
+namespace Agrirouter.Test.Service.Messaging.Mqtt
+{
+    [Collection("Integrationtest")]
+    public class PingServiceTest : AbstractIntegrationTestForCommunicationUnits
+    {
+        [Fact]
+        public async void
+            GivenExistingEndpointWhenSendingPingThenShouldBeSuccessful()
+        {
+            var mqttClient = new MqttFactory().CreateMqttClient();
+
+            await MqttConnectionHelper.ConnectMqttClient(mqttClient, OnboardResponse);
+            await MqttConnectionHelper.SubscribeToTopics(mqttClient, OnboardResponse);
+
+            var pingService = new PingService(new MqttMessagingService(mqttClient));
+            var pingParameters = new PingParameters()
+            {
+                OnboardResponse = OnboardResponse
+            };
+
+            pingService.Send(pingParameters);
+
+            var messageReceived = false;
+            var counter = 0;
+
+            mqttClient.UseApplicationMessageReceivedHandler(e =>
+            {
+                messageReceived = true;
+
+                var msg = JsonConvert.DeserializeObject<MessageResponse>(
+                    Encoding.UTF8.GetString(e.ApplicationMessage.Payload));
+                var decodedMessage = DecodeMessageService.Decode(msg.Command.Message);
+
+                Assert.Equal(200, decodedMessage.ResponseEnvelope.ResponseCode);
+            });
+
+            while (!messageReceived && counter < 5)
+            {
+                await Task.Delay(TimeSpan.FromSeconds(5));
+                counter++;
+            }
+
+            Assert.True(messageReceived);
+        }
+
+        private static OnboardResponse OnboardResponse =>
+            OnboardResponseIntegrationService.Read(Identifier.Mqtt.CommunicationUnit.SingleEndpointWithP12Certificate);
+
+
+        [Fact(Skip =
+            "Concept only: A deleted endpoint can not be tested automatically and requires some manual actions.")]
+        public async void
+            GivenRecentlyDeletedEndpointWhenSendingPingThenShouldReturn400()
+        {
+            // This test case can not run. We have no Router Device based tests currently, and this command only
+            // makes sense with a Router Device.
+            // It is only intended to show the concept of the test case.
+
+            var mqttClient = new MqttFactory().CreateMqttClient();
+
+            await MqttConnectionHelper.ConnectMqttClient(mqttClient, OnboardResponse);
+            await MqttConnectionHelper.SubscribeToTopics(mqttClient, OnboardResponse);
+
+            // Endpoint would need to be deleted here
+            // if it was deleted earlier, the connection wouldn't be possible
+
+            var pingService = new PingService(new MqttMessagingService(mqttClient));
+            var pingParameters = new PingParameters()
+            {
+                OnboardResponse = OnboardResponse
+            };
+
+            pingService.Send(pingParameters);
+
+            var messageReceived = false;
+            var counter = 0;
+
+            mqttClient.UseApplicationMessageReceivedHandler(e =>
+            {
+                messageReceived = true;
+
+                var msg = JsonConvert.DeserializeObject<MessageResponse>(
+                    Encoding.UTF8.GetString(e.ApplicationMessage.Payload));
+                var decodedMessage = DecodeMessageService.Decode(msg.Command.Message);
+
+                // your own application should remove the endpoint from your endpoint list/registry now!
+                Assert.Equal(400, decodedMessage.ResponseEnvelope.ResponseCode);
+            });
+
+            while (!messageReceived && counter < 5)
+            {
+                await Task.Delay(TimeSpan.FromSeconds(5));
+                counter++;
+            }
+
+            Assert.True(messageReceived);
+        }
+    }
+}