Como: implementar um serviço de descoberta que registra usando o proxy de descoberta

Artigo
06/10/2024

Este tópico é o segundo de quatro tópicos que aborda como implementar um proxy de descoberta. No tópico anterior, Como implementar um proxy de descoberta, você implementou um proxy de descoberta. Neste tópico, você criará um serviço WCF que envia mensagens de comunicado (Hello e Bye) para o proxy de descoberta, fazendo com que ele se registre e cancele o registro no proxy de descoberta.

Para definir um contrato de serviço

Adicione um novo projeto de aplicativo de console chamado Service à solução DiscoveryProxyExample.
Adicione referências aos assemblies a seguir:
1. System.ServiceModel
2. System.ServiceModel.Discovery
Adicione uma nova classe chamada CalculatorService ao projeto.

Adicione as diretivas using a seguir.

using System;
using System.ServiceModel;

Em CalculatorService.cs, defina o contrato de serviço.

// Define a service contract.
[ServiceContract(Namespace = "http://Microsoft.Samples.Discovery")]
public interface ICalculatorService
{
    [OperationContract]
    double Add(double n1, double n2);
    [OperationContract]
    double Subtract(double n1, double n2);
    [OperationContract]
    double Multiply(double n1, double n2);
    [OperationContract]
    double Divide(double n1, double n2);
}

Também em CalculatorService.cs, implemente o contrato de serviço.

// Service class which implements the service contract.
public class CalculatorService : ICalculatorService
{
    public double Add(double n1, double n2)
    {
        double result = n1 + n2;
        Console.WriteLine("Received Add({0},{1})", n1, n2);
        Console.WriteLine("Return: {0}", result);
        return result;
    }

    public double Subtract(double n1, double n2)
    {
        double result = n1 - n2;
        Console.WriteLine("Received Subtract({0},{1})", n1, n2);
        Console.WriteLine("Return: {0}", result);
        return result;
    }

    public double Multiply(double n1, double n2)
    {
        double result = n1 * n2;
        Console.WriteLine("Received Multiply({0},{1})", n1, n2);
        Console.WriteLine("Return: {0}", result);
        return result;
    }

    public double Divide(double n1, double n2)
    {
        double result = n1 / n2;
        Console.WriteLine("Received Divide({0},{1})", n1, n2);
        Console.WriteLine("Return: {0}", result);
        return result;
    }
}

Para hospedar o serviço

Abra o arquivo Program.cs que foi gerado quando você criou o projeto.

Adicione as diretivas using a seguir.

using System;
using System.ServiceModel;
using System.ServiceModel.Description;
using System.ServiceModel.Discovery;

Dentro do método Main(), adicione o seguinte código:

// Define the base address of the service
Uri baseAddress = new Uri("net.tcp://localhost:9002/CalculatorService/" + Guid.NewGuid().ToString());
// Define the endpoint address where announcement messages will be sent
Uri announcementEndpointAddress = new Uri("net.tcp://localhost:9021/Announcement");

// Create the service host
ServiceHost serviceHost = new ServiceHost(typeof(CalculatorService), baseAddress);
try
{
    // Add a service endpoint
    ServiceEndpoint netTcpEndpoint = serviceHost.AddServiceEndpoint(typeof(ICalculatorService),
        new NetTcpBinding(), string.Empty);

    // Create an announcement endpoint, which points to the Announcement Endpoint hosted by the proxy service.
    AnnouncementEndpoint announcementEndpoint = new AnnouncementEndpoint(new NetTcpBinding(),
        new EndpointAddress(announcementEndpointAddress));

    // Create a ServiceDiscoveryBehavior and add the announcement endpoint
    ServiceDiscoveryBehavior serviceDiscoveryBehavior = new ServiceDiscoveryBehavior();
    serviceDiscoveryBehavior.AnnouncementEndpoints.Add(announcementEndpoint);

    // Add the ServiceDiscoveryBehavior to the service host to make the service discoverable
    serviceHost.Description.Behaviors.Add(serviceDiscoveryBehavior);

    // Start listening for messages
    serviceHost.Open();

    Console.WriteLine("Calculator Service started at {0}", baseAddress);
    Console.WriteLine();
    Console.WriteLine("Press <ENTER> to terminate the service.");
    Console.WriteLine();
    Console.ReadLine();

    serviceHost.Close();
}
catch (CommunicationException e)
{
    Console.WriteLine(e.Message);
}
catch (TimeoutException e)
{
    Console.WriteLine(e.Message);
}

if (serviceHost.State != CommunicationState.Closed)
{
    Console.WriteLine("Aborting the service...");
    serviceHost.Abort();
}

Você concluiu a implementação de um serviço detectável. Prossiga para Como implementar um aplicativo cliente que usa o proxy de descoberta para localizar um serviço.

Exemplo

Esta é a lista completa do código usado neste tópico.

// CalculatorService.cs
//----------------------------------------------------------------
// Copyright (c) Microsoft Corporation.  All rights reserved.
//----------------------------------------------------------------

using System;
using System.ServiceModel;

namespace Microsoft.Samples.Discovery
{
    // Define a service contract.
    [ServiceContract(Namespace = "http://Microsoft.Samples.Discovery")]
    public interface ICalculatorService
    {
        [OperationContract]
        double Add(double n1, double n2);
        [OperationContract]
        double Subtract(double n1, double n2);
        [OperationContract]
        double Multiply(double n1, double n2);
        [OperationContract]
        double Divide(double n1, double n2);
    }

    // Service class which implements the service contract.
    public class CalculatorService : ICalculatorService
    {
        public double Add(double n1, double n2)
        {
            double result = n1 + n2;
            Console.WriteLine("Received Add({0},{1})", n1, n2);
            Console.WriteLine("Return: {0}", result);
            return result;
        }

        public double Subtract(double n1, double n2)
        {
            double result = n1 - n2;
            Console.WriteLine("Received Subtract({0},{1})", n1, n2);
            Console.WriteLine("Return: {0}", result);
            return result;
        }

        public double Multiply(double n1, double n2)
        {
            double result = n1 * n2;
            Console.WriteLine("Received Multiply({0},{1})", n1, n2);
            Console.WriteLine("Return: {0}", result);
            return result;
        }

        public double Divide(double n1, double n2)
        {
            double result = n1 / n2;
            Console.WriteLine("Received Divide({0},{1})", n1, n2);
            Console.WriteLine("Return: {0}", result);
            return result;
        }
    }
}

// Program.cs
//----------------------------------------------------------------
// Copyright (c) Microsoft Corporation.  All rights reserved.
//----------------------------------------------------------------

using System;
using System.ServiceModel;
using System.ServiceModel.Description;
using System.ServiceModel.Discovery;

namespace Microsoft.Samples.Discovery
{
    class Program
    {
        public static void Main()
        {
            Uri baseAddress = new Uri("net.tcp://localhost:9002/CalculatorService/" + Guid.NewGuid().ToString());
            Uri announcementEndpointAddress = new Uri("net.tcp://localhost:9021/Announcement");

            ServiceHost serviceHost = new ServiceHost(typeof(CalculatorService), baseAddress);
            try
            {
                ServiceEndpoint netTcpEndpoint = serviceHost.AddServiceEndpoint(typeof(ICalculatorService),
                    new NetTcpBinding(), string.Empty);

                // Create an announcement endpoint, which points to the Announcement Endpoint hosted by the proxy service.
                AnnouncementEndpoint announcementEndpoint = new AnnouncementEndpoint(new NetTcpBinding(),
                    new EndpointAddress(announcementEndpointAddress));

                ServiceDiscoveryBehavior serviceDiscoveryBehavior = new ServiceDiscoveryBehavior();
                serviceDiscoveryBehavior.AnnouncementEndpoints.Add(announcementEndpoint);

                // Make the service discoverable
                serviceHost.Description.Behaviors.Add(serviceDiscoveryBehavior);

                serviceHost.Open();

                Console.WriteLine("Calculator Service started at {0}", baseAddress);
                Console.WriteLine();
                Console.WriteLine("Press <ENTER> to terminate the service.");
                Console.WriteLine();
                Console.ReadLine();

                serviceHost.Close();
            }
            catch (CommunicationException e)
            {
                Console.WriteLine(e.Message);
            }
            catch (TimeoutException e)
            {
                Console.WriteLine(e.Message);
            }

            if (serviceHost.State != CommunicationState.Closed)
            {
                Console.WriteLine("Aborting the service...");
                serviceHost.Abort();
            }
        }
    }
}

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Como: implementar um serviço de descoberta que registra usando o proxy de descoberta

Para definir um contrato de serviço

Para hospedar o serviço

Exemplo

Confira também

Recursos adicionais