Inbound call with IVR menu: appointment booking

CallAutomation_AppointmentBooking/CallAutomation_AppointmentBooking.sln

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+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
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+		{E0A69614-B3D9-446A-B9BC-D7D21B4A2DF8}.Debug|Any CPU.Build.0 = Debug|Any CPU
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+		{E0A69614-B3D9-446A-B9BC-D7D21B4A2DF8}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
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+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
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+	EndGlobalSection
+EndGlobal

CallAutomation_AppointmentBooking/CallAutomation_AppointmentBooking/AppointmentBookingConfig.cs

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+namespace CallAutomation_AppointmentBooking
+{
+    public class AppointmentBookingConfig
+    {
+        /// <summary>
+        /// public Callback URI that will be used to answer incoming call event,
+        /// or handle mid-call events, such as CallConnected.
+        /// See README file for details on how to setup tunnel on your localhost to handle this.
+        /// </summary>
+        public Uri CallbackUri { get; init; }
+
+        /// <summary>
+        /// DirectOffered phonenumber is can be aquired from Azure Communication Service portal.
+        /// In order to answer Incoming PSTN call or make an outbound call to PSTN number,
+        /// Call Automation needs Directly offered PSTN number to do these actions.
+        /// </summary>
+        public string DirectOfferedPhonenumber { get; init; }
+
+        /// <summary>
+        /// List of all prompts from this sample's business logic.
+        /// These recorded prompts must be uploaded to publicily available Uri endpoint.
+        /// See README for pre-generated samples that can be used for demo.
+        /// </summary>
+        public Prompts AllPrompts { get; init; }
+
+        public class Prompts
+        {
+            public Uri MainMenu { get; init; }
+
+            public Uri Retry { get; init; }
+
+            public Uri Choice1 { get; init; }
+
+            public Uri Choice2 { get; init; }
+
+            public Uri Choice3 { get; init; }
+
+            public Uri PlayRecordingStarted { get; init; }
+
+            public Uri Goodbye { get; init; }
+        }
+    }
+}

CallAutomation_AppointmentBooking/CallAutomation_AppointmentBooking/CallAutomation_AppointmentBooking.csproj

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+<Project Sdk="Microsoft.NET.Sdk.Web">
+
+  <PropertyGroup>
+    <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <UserSecretsId>d7d2fc43-754d-4dba-87ed-832e765c7a4d</UserSecretsId>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Azure.Communication.CallAutomation" Version="1.0.0-alpha.20230516.1" />
+    <PackageReference Include="Azure.Messaging.EventGrid" Version="4.16.0" />
+    <PackageReference Include="Swashbuckle.AspNetCore" Version="6.2.3" />
+  </ItemGroup>
+
+</Project>

CallAutomation_AppointmentBooking/CallAutomation_AppointmentBooking/CallingModules.cs

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+using Azure.Communication;
+using Azure.Communication.CallAutomation;
+using CallAutomation_AppointmentBooking.Interfaces; 
+
+namespace CallAutomation_AppointmentBooking
+{
+    /// <summary>
+    /// Reusuable common calling actions for business needs
+    /// </summary>
+    public class CallingModules : ICallingModules
+    {
+        private readonly CallConnection _callConnection;
+        private readonly AppointmentBookingConfig _appointmentBookingConfig;
+
+        public CallingModules(
+            CallConnection callConnection,
+            AppointmentBookingConfig appointmentBookingConfig)
+        {
+            _callConnection = callConnection;
+            _appointmentBookingConfig = appointmentBookingConfig;
+        }
+
+        public async Task<string> RecognizeTonesAsync(
+            CommunicationIdentifier targetToRecognize,
+            int minDigitToCollect,
+            int maxDigitToCollect,
+            Uri askPrompt,
+            Uri retryPrompt)
+        {
+            for (int i = 0; i < 3; i++)
+            {
+                // prepare recognize tones
+                CallMediaRecognizeDtmfOptions callMediaRecognizeDtmfOptions = new CallMediaRecognizeDtmfOptions(targetToRecognize, maxDigitToCollect);
+                callMediaRecognizeDtmfOptions.Prompt = new FileSource(askPrompt);
+                callMediaRecognizeDtmfOptions.InterruptPrompt = true;
+                callMediaRecognizeDtmfOptions.InitialSilenceTimeout = TimeSpan.FromSeconds(10);
+                callMediaRecognizeDtmfOptions.InterToneTimeout = TimeSpan.FromSeconds(10);
+                callMediaRecognizeDtmfOptions.StopTones = new List<DtmfTone> { DtmfTone.Pound, DtmfTone.Asterisk };
+
+                // Send request to recognize tones
+                StartRecognizingCallMediaResult startRecognizingResult = await _callConnection.GetCallMedia().StartRecognizingAsync(callMediaRecognizeDtmfOptions);
+
+                // Wait for recognize related event...
+                StartRecognizingEventResult recognizeEventResult = await startRecognizingResult.WaitForEventProcessorAsync();
+
+                if (recognizeEventResult.IsSuccess)
+                {
+                    // success recognition - return the tones detected.
+                    RecognizeCompleted recognizeCompleted = recognizeEventResult.SuccessResult;
+                    string dtmfTones = ((DtmfResult)recognizeCompleted.RecognizeResult).ConvertToString();
+
+                    // check if it collected the minimum digit it collected
+                    if (dtmfTones.Length >= minDigitToCollect)
+                    {
+                        return dtmfTones;
+                    }
+                }
+                else
+                {
+                    // failed recognition - likely timeout
+                    _ = recognizeEventResult.FailureResult;
+                }
+
+                // play retry prompt and retry again
+                await PlayMessageThenWaitUntilItEndsAsync(retryPrompt);
+            }
+
+            throw new Exception("Retried 3 times, Failed to get tones.");
+        }
+
+
+        public async Task PlayMessageThenWaitUntilItEndsAsync(Uri playPrompt)
+        {
+            // Play failure prompt and retry.
+            FileSource fileSource = new FileSource(playPrompt);
+            PlayResult playResult = await _callConnection.GetCallMedia().PlayToAllAsync(fileSource);
+
+            // ... wait for play to complete, then return
+            await playResult.WaitForEventProcessorAsync();
+        }
+
+        public async Task TerminateCallAsync()
+        {
+            // Terminate the call
+            await _callConnection.HangUpAsync(true);
+        }
+    }
+}

CallAutomation_AppointmentBooking/CallAutomation_AppointmentBooking/Controllers/EventController.cs

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+using Azure.Communication.CallAutomation;
+using Azure.Messaging;
+using Microsoft.AspNetCore.Mvc;
+
+namespace CallAutomation_AppointmentBooking.Controllers
+{
+    /// <summary>
+    /// This is controller where it will recieve interim events from Call automation service.
+    /// We are utilizing event processor, this will handle events and relay to our business logic.
+    /// </summary>
+    [Route("api/[controller]")]
+    [ApiController]
+    public class EventController : ControllerBase
+    {
+        private readonly ILogger<EventController> _logger;
+        private readonly CallAutomationEventProcessor _eventProcessor;
+
+        public EventController(
+            ILogger<EventController> logger,
+            CallAutomationClient callAutomationClient)
+        {
+            _logger = logger;
+            _eventProcessor = callAutomationClient.GetEventProcessor();
+        }
+
+        [HttpPost]
+        public IActionResult CallbackEvent([FromBody] CloudEvent[] cloudEvents)
+        {
+            // Prase incoming event into solid base class of CallAutomationEvent.
+            // This is useful when we want to access the properties of the event easily, such as CallConnectionId.
+            // We are using this parsed event to log CallconnectionId of the event here.
+            CallAutomationEventBase? parsedBaseEvent = CallAutomationEventParser.ParseMany(cloudEvents).FirstOrDefault();            
+            _logger.LogInformation($"Event Recieved. CallConnectionId[{parsedBaseEvent?.CallConnectionId}], Type Name[{parsedBaseEvent?.GetType().Name}]");
+
+            // Utilizing evnetProcessor here to easily handle mid-call call automation events.
+            // process event into processor, so events could be handled in CallingModule.
+            _eventProcessor.ProcessEvents(cloudEvents);
+            return Ok();
+        }
+    }
+}

CallAutomation_AppointmentBooking/CallAutomation_AppointmentBooking/Controllers/IncomingCallController.cs

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+using Azure.Communication;
+using Azure.Communication.CallAutomation;
+using Azure.Messaging.EventGrid;
+using Azure.Messaging.EventGrid.SystemEvents;
+using CallAutomation_AppointmentBooking.Interfaces;
+using Microsoft.AspNetCore.Mvc;
+
+namespace CallAutomation_AppointmentBooking.Controllers
+{
+    /// <summary>
+    /// This is the controller for recieving an inbound call.
+    /// See README files how to setup incoming call and its incoming call event
+    /// </summary>
+    [Route("api/[controller]")]
+    [ApiController]
+    public class IncomingCallController : ControllerBase
+    {
+        private readonly ILogger<IncomingCallController> _logger;
+        private readonly CallAutomationClient _callAutomationClient;
+        private readonly AppointmentBookingConfig _appointmentBookingConfig;
+        private readonly ITopLevelMenuService _topLevelMenuService;
+        private readonly IOngoingEventHandler _ongoingEventHandler;
+
+        public IncomingCallController(
+            ILogger<IncomingCallController> logger,
+            CallAutomationClient callAutomationClient,
+            AppointmentBookingConfig appointmentBookingConfig,
+            ITopLevelMenuService topLevelMenuService,
+            IOngoingEventHandler ongoingEventHandler)
+        {
+            _logger = logger;
+            _callAutomationClient = callAutomationClient;
+            _appointmentBookingConfig = appointmentBookingConfig;
+            _topLevelMenuService = topLevelMenuService;
+            _ongoingEventHandler = ongoingEventHandler;
+        }
+
+        [HttpPost]
+        public async Task<IActionResult> IncomingCall([FromBody] object request)
+        {
+            string callConnectionId = string.Empty;
+            try
+            {
+                // Parse incoming call event using eventgrid parser
+                var httpContent = new BinaryData(request.ToString());
+                EventGridEvent cloudEvent = EventGridEvent.ParseMany(httpContent).First();
+
+                if (cloudEvent.EventType == SystemEventNames.EventGridSubscriptionValidation)
+                {
+                    // this section is for handling initial handshaking with Event webhook registration
+                    var eventData = cloudEvent.Data.ToObjectFromJson<SubscriptionValidationEventData>();
+                    var responseData = new SubscriptionValidationResponse
+                    {
+                        ValidationResponse = eventData.ValidationCode
+                    };
+
+                    if (responseData.ValidationResponse != null)
+                    {
+                        _logger.LogInformation($"Incoming EventGrid event: Handshake Successful.");
+                        return Ok(responseData);
+                    }
+                }
+                else if (cloudEvent.EventType == SystemEventNames.AcsIncomingCall)
+                {
+                    // parse again the data into ACS incomingCall event
+                    AcsIncomingCallEventData incomingCallEventData = cloudEvent.Data.ToObjectFromJson<AcsIncomingCallEventData>();
+
+                    // Answer Incoming call with incoming call event data
+                    // IncomingCallContext can be used to answer the call
+                    AnswerCallResult answerCallResult = await _callAutomationClient.AnswerCallAsync(incomingCallEventData.IncomingCallContext, _appointmentBookingConfig.CallbackUri);
+                    callConnectionId = answerCallResult.CallConnectionProperties.CallConnectionId;
+
+                    _ = Task.Run(async () =>
+                    {
+                        // attaching ongoing event handler for specific events
+                        // This is useful for handling unexpected events could happen anytime (such as participants leaves the call and cal is disconnected)
+                        _ongoingEventHandler.AttachCountParticipantsInTheCall(callConnectionId);
+                        _ongoingEventHandler.AttachDisconnectedWrapup(callConnectionId);
+
+                        // Wait for call to be connected.
+                        // Wait for 40 seconds before throwing timeout error.
+                        var tokenSource = new CancellationTokenSource(TimeSpan.FromSeconds(40));
+                        AnswerCallEventResult eventResult = await answerCallResult.WaitForEventProcessorAsync(tokenSource.Token);
+
+                        if (eventResult.IsSuccess)
+                        {
+                            // call connected returned! Call is now established.
+                            // invoke top level menu now the call is connected;
+                            await _topLevelMenuService.InvokeTopLevelMenu(
+                                CommunicationIdentifier.FromRawId(incomingCallEventData.FromCommunicationIdentifier.RawId),
+                                answerCallResult.CallConnection,
+                                eventResult.SuccessResult.ServerCallId);
+                        }
+                    });
+                }
+            }
+            catch (Exception e)
+            {
+                // Exception! Failed to answer the call.
+                _logger.LogError($"Exception while answer the call. CallConnectionId[{callConnectionId}], Exception[{e}]");
+            }
+
+            return Ok();
+        }
+    }
+}

CallAutomation_AppointmentBooking/CallAutomation_AppointmentBooking/Interfaces/ICallingModules.cs

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+using Azure.Communication.CallAutomation;
+using Azure.Communication;
+
+namespace CallAutomation_AppointmentBooking.Interfaces
+{
+    public interface ICallingModules
+    {
+        Task<string> RecognizeTonesAsync(CommunicationIdentifier targetToRecognize, int minDigitToCollect, int maxDigitToCollect, Uri askPrompt, Uri retryPrompt);
+
+        Task PlayMessageThenWaitUntilItEndsAsync(Uri playPrompt);
+
+        Task TerminateCallAsync();
+    }
+}

CallAutomation_AppointmentBooking/CallAutomation_AppointmentBooking/Interfaces/IOngoingEventHandler.cs

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+using Azure.Communication;
+using Azure.Communication.CallAutomation;
+
+namespace CallAutomation_AppointmentBooking.Interfaces
+{   
+    public interface IOngoingEventHandler
+    {
+        void AttachCountParticipantsInTheCall(string callConnectionId);
+
+        void AttachDisconnectedWrapup(string callConnectionId);
+    }
+}

CallAutomation_AppointmentBooking/CallAutomation_AppointmentBooking/Interfaces/ITopLevelMenuService.cs

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+using Azure.Communication;
+using Azure.Communication.CallAutomation;
+
+namespace CallAutomation_AppointmentBooking.Interfaces
+{
+    public interface ITopLevelMenuService
+    {
+        Task InvokeTopLevelMenu(CommunicationIdentifier originalTarget, CallConnection callConnection, string serverCallId);
+    }
+}