Postupy: Výměna zpráv zařazených do fronty pomocí koncových bodů WCF

Článek
03/05/2024

Fronty zajišťují, aby mezi klientem a službou WCF (Windows Communication Foundation) mohlo dojít k spolehlivému zasílání zpráv, i když služba není v době komunikace dostupná. Následující postupy ukazují, jak zajistit trvalou komunikaci mezi klientem a službou pomocí standardní vazby ve frontě při implementaci služby WCF.

Tato část vysvětluje, jak se používá NetMsmqBinding pro komunikaci ve frontě mezi klientem WCF a službou WCF.

Použití řazení front ve službě WCF

Definujte kontrakt služby pomocí rozhraní označeného symbolem ServiceContractAttribute. Označte operace v rozhraní, které jsou součástí kontraktu služby, OperationContractAttribute a zadejte je jako jednosměrný, protože není vrácena žádná odpověď na metodu. Následující kód poskytuje příklad kontraktu služby a jeho definice operace.

[ServiceContract(Namespace="http://Microsoft.ServiceModel.Samples")]
public interface IOrderProcessor
{
    [OperationContract(IsOneWay = true)]
    void SubmitPurchaseOrder(PurchaseOrder po);
}

<ServiceContract(Namespace:="http://Microsoft.ServiceModel.Samples")> _
Public Interface IOrderProcessor
    <OperationContract(IsOneWay:=True)> _
    Sub SubmitPurchaseOrder(ByVal po As PurchaseOrder)
End Interface

Když kontrakt služby předává uživatelem definované typy, musíte pro tyto typy definovat datové kontrakty. Následující kód ukazuje dva kontrakty PurchaseOrder dat a PurchaseOrderLineItem. Tyto dva typy definují data odesílaná do služby. (Všimněte si, že třídy, které definují tento datový kontrakt, také definují řadu metod. Tyto metody se nepovažují za součást kontraktu dat. Součástí datového kontraktu DataMemberAttribute jsou pouze členové deklarované s atributem.)

[DataContract(Namespace = "http://Microsoft.ServiceModel.Samples")]
public class PurchaseOrder
{
    static readonly string[] OrderStates = { "Pending", "Processed", "Shipped" };
    static Random statusIndexer = new Random(137);

    [DataMember]
    public string PONumber;

    [DataMember]
    public string CustomerId;

    [DataMember]
    public PurchaseOrderLineItem[] orderLineItems;

    public float TotalCost
    {
        get
        {
            float totalCost = 0;
            foreach (PurchaseOrderLineItem lineItem in orderLineItems)
                totalCost += lineItem.TotalCost;
            return totalCost;
        }
    }

    public string Status
    {
        get
        {
            return OrderStates[statusIndexer.Next(3)];
        }
    }

    public override string ToString()
    {
        System.Text.StringBuilder strbuf = new System.Text.StringBuilder("Purchase Order: " + PONumber + "\n");
        strbuf.Append("\tCustomer: " + CustomerId + "\n");
        strbuf.Append("\tOrderDetails\n");

        foreach (PurchaseOrderLineItem lineItem in orderLineItems)
        {
            strbuf.Append("\t\t" + lineItem.ToString());
        }

        strbuf.Append("\tTotal cost of this order: $" + TotalCost + "\n");
        strbuf.Append("\tOrder status: " + Status + "\n");
        return strbuf.ToString();
    }
}

<DataContract(Namespace:="http://Microsoft.ServiceModel.Samples")> _
Public Class PurchaseOrder
    Private Shared ReadOnly OrderStates() As String = {"Pending", "Processed", "Shipped"}
    Private Shared statusIndexer As New Random(137)

    <DataMember> _
    Public PONumber As String

    <DataMember> _
    Public CustomerId As String

    <DataMember> _
    Public orderLineItems() As PurchaseOrderLineItem

    Public ReadOnly Property TotalCost() As Single
        Get
            Dim totalCost_Renamed As Single = 0
            For Each lineItem In orderLineItems
                totalCost_Renamed += lineItem.TotalCost
            Next lineItem
            Return totalCost_Renamed
        End Get
    End Property

    Public ReadOnly Property Status() As String
        Get
            Return OrderStates(statusIndexer.Next(3))
        End Get
    End Property

    Public Overrides Function ToString() As String
        Dim strbuf As New System.Text.StringBuilder("Purchase Order: " & PONumber & Constants.vbLf)
        strbuf.Append(Constants.vbTab & "Customer: " & CustomerId & Constants.vbLf)
        strbuf.Append(Constants.vbTab & "OrderDetails" & Constants.vbLf)

        For Each lineItem In orderLineItems
            strbuf.Append(Constants.vbTab + Constants.vbTab + lineItem.ToString())
        Next lineItem

        strbuf.Append(Constants.vbTab & "Total cost of this order: $" & TotalCost + Constants.vbLf)
        strbuf.Append(Constants.vbTab & "Order status: " & Status + Constants.vbLf)
        Return strbuf.ToString()
    End Function
End Class

Implementujte metody kontraktu služby definovaného v rozhraní ve třídě.

public class OrderProcessorService : IOrderProcessor
{
    [OperationBehavior(TransactionScopeRequired = true, TransactionAutoComplete = true)]
    public void SubmitPurchaseOrder(PurchaseOrder po)
    {
        Orders.Add(po);
        Console.WriteLine("Processing {0} ", po);
    }
}

Public Class OrderProcessorService
    Implements IOrderProcessor
    <OperationBehavior(TransactionScopeRequired:=True, TransactionAutoComplete:=True)> _
    Public Sub SubmitPurchaseOrder(ByVal po As PurchaseOrder) Implements IOrderProcessor.SubmitPurchaseOrder
        Orders.Add(po)
        Console.WriteLine("Processing {0} ", po)
    End Sub
End Class

Všimněte si OperationBehaviorAttribute umístění metody SubmitPurchaseOrder . Určuje, že tato operace musí být volána v rámci transakce a že transakce se automaticky dokončí po dokončení metody.

Vytvoření transakční fronty pomocí System.Messaging. Místo toho můžete vytvořit frontu pomocí konzoly Microsoft Management Console (MSMQ) Microsoft Message Queuing (MMC). Pokud ano, ujistěte se, že jste vytvořili transakční frontu.

// Create the transacted MSMQ queue if necessary.
if (!MessageQueue.Exists(queueName))
    MessageQueue.Create(queueName, true);

' Create the transacted MSMQ queue if necessary.
If (Not MessageQueue.Exists(queueName)) Then
    MessageQueue.Create(queueName, True)
End If

ServiceEndpoint Definujte v konfiguraci, která určuje adresu služby a používá standardní NetMsmqBinding vazbu. Další informace o použití konfigurace WCF naleznete v tématu Konfigurace služeb WCF.

Vytvořte hostitele pro OrderProcessing službu, ServiceHost který čte zprávy z fronty a zpracovává je. Otevřete hostitele služby, aby byla služba dostupná. Zobrazí zprávu, která uživateli oznámí, že má službu ukončit stisknutím libovolné klávesy. Zavolejte ReadLine a počkejte, až se stiskne klávesa, a pak službu zavřete.

// Create a ServiceHost for the OrderProcessorService type.
using (ServiceHost serviceHost = new ServiceHost(typeof(OrderProcessorService)))
{
    // Open the ServiceHost to create listeners and start listening for messages.
    serviceHost.Open();

    // The service can now be accessed.
    Console.WriteLine("The service is ready.");
    Console.WriteLine("Press <ENTER> to terminate service.");
    Console.WriteLine();
    Console.ReadLine();

    // Close the ServiceHostB to shutdown the service.
    serviceHost.Close();
}

' Create a ServiceHost for the OrderProcessorService type.
Using serviceHost As New ServiceHost(GetType(OrderProcessorService))
    ' Open the ServiceHost to create listeners and start listening for messages.
    serviceHost.Open()

    ' The service can now be accessed.
    Console.WriteLine("The service is ready.")
    Console.WriteLine("Press <ENTER> to terminate service.")
    Console.WriteLine()
    Console.ReadLine()

    ' Close the ServiceHostB to shutdown the service.
    serviceHost.Close()
End Using

Vytvoření klienta pro službu ve frontě

Následující příklad ukazuje, jak spustit hostující aplikaci a pomocí nástroje Svcutil.exe vytvořit klienta WCF.
```
svcutil http://localhost:8000/ServiceModelSamples/service  
```
ServiceEndpoint Definujte v konfiguraci, která určuje adresu a používá standardní NetMsmqBinding vazbu, jak je znázorněno v následujícím příkladu.

Vytvořte obor transakce pro zápis do transakční fronty, volání SubmitPurchaseOrder operace a zavření klienta WCF, jak je znázorněno v následujícím příkladu.

//Create a transaction scope.
using (TransactionScope scope = new TransactionScope(TransactionScopeOption.Required))
{
    // Make a queued call to submit the purchase order.
    client.SubmitPurchaseOrder(po);
    // Complete the transaction.
    scope.Complete();
}

//Closing the client gracefully closes the connection and cleans up resources.
client.Close();

'Create a transaction scope.
Using scope As New TransactionScope(TransactionScopeOption.Required)
    ' Make a queued call to submit the purchase order.
    client.SubmitPurchaseOrder(po)
    ' Complete the transaction.
    scope.Complete()
End Using

'Closing the client gracefully closes the connection and cleans up resources.
client.Close()

Příklad

Následující příklady ukazují kód služby, hostující aplikaci, soubor App.config a kód klienta, které jsou součástí tohoto příkladu.

// This is the service code
//  Copyright (c) Microsoft Corporation.  All Rights Reserved.

using System;
using System.ServiceModel.Channels;
using System.Configuration;
using System.Messaging;
using System.ServiceModel;
using System.Transactions;
using System.Runtime.Serialization;
using System.Collections.Generic;

namespace Microsoft.ServiceModel.Samples
{
    // Define the purchase order line item.
    [DataContract(Namespace = "http://Microsoft.ServiceModel.Samples")]
    public class PurchaseOrderLineItem
    {
        [DataMember]
        public string ProductId;

        [DataMember]
        public float UnitCost;

        [DataMember]
        public int Quantity;

        public override string ToString()
        {
            String displayString = "Order LineItem: " + Quantity + " of "  + ProductId + " @unit price: $" + UnitCost + "\n";
            return displayString;
        }

        public float TotalCost
        {
            get { return UnitCost * Quantity; }
        }
    }

    // Define the purchase order.
    [DataContract(Namespace = "http://Microsoft.ServiceModel.Samples")]
    public class PurchaseOrder
    {
        static readonly string[] OrderStates = { "Pending", "Processed", "Shipped" };
        static Random statusIndexer = new Random(137);

        [DataMember]
        public string PONumber;

        [DataMember]
        public string CustomerId;

        [DataMember]
        public PurchaseOrderLineItem[] orderLineItems;

        public float TotalCost
        {
            get
            {
                float totalCost = 0;
                foreach (PurchaseOrderLineItem lineItem in orderLineItems)
                    totalCost += lineItem.TotalCost;
                return totalCost;
            }
        }

        public string Status
        {
            get
            {
                return OrderStates[statusIndexer.Next(3)];
            }
        }

        public override string ToString()
        {
            System.Text.StringBuilder strbuf = new System.Text.StringBuilder("Purchase Order: " + PONumber + "\n");
            strbuf.Append("\tCustomer: " + CustomerId + "\n");
            strbuf.Append("\tOrderDetails\n");

            foreach (PurchaseOrderLineItem lineItem in orderLineItems)
            {
                strbuf.Append("\t\t" + lineItem.ToString());
            }

            strbuf.Append("\tTotal cost of this order: $" + TotalCost + "\n");
            strbuf.Append("\tOrder status: " + Status + "\n");
            return strbuf.ToString();
        }
    }

    // Order Processing Logic
    // Can replace with transaction-aware resource such as SQL or transacted hashtable to hold the purchase orders.
    // This example uses a non-transactional resource.
    public class Orders
    {
        static Dictionary<string, PurchaseOrder> purchaseOrders = new Dictionary<string, PurchaseOrder>();

        public static void Add(PurchaseOrder po)
        {
            purchaseOrders.Add(po.PONumber, po);
        }

        public static string GetOrderStatus(string poNumber)
        {
            PurchaseOrder po;
            if (purchaseOrders.TryGetValue(poNumber, out po))
                return po.Status;
            else
                return null;
        }

        public static void DeleteOrder(string poNumber)
        {
            if(purchaseOrders[poNumber] != null)
                purchaseOrders.Remove(poNumber);
        }
    }

    // Define a service contract.
    [ServiceContract(Namespace="http://Microsoft.ServiceModel.Samples")]
    public interface IOrderProcessor
    {
        [OperationContract(IsOneWay = true)]
        void SubmitPurchaseOrder(PurchaseOrder po);
    }

    // Service class that implements the service contract.
    // Added code to write output to the console window.
    public class OrderProcessorService : IOrderProcessor
    {
        [OperationBehavior(TransactionScopeRequired = true, TransactionAutoComplete = true)]
        public void SubmitPurchaseOrder(PurchaseOrder po)
        {
            Orders.Add(po);
            Console.WriteLine("Processing {0} ", po);
        }
    }
}

' This is the service code
'  Copyright (c) Microsoft Corporation.  All Rights Reserved.

Imports System.ServiceModel.Channels
Imports System.Configuration
Imports System.Messaging
Imports System.ServiceModel
Imports System.Transactions
Imports System.Runtime.Serialization
Imports System.Collections.Generic

Namespace Microsoft.ServiceModel.Samples
    ' Define the purchase order line item.
    <DataContract(Namespace:="http://Microsoft.ServiceModel.Samples")> _
    Public Class PurchaseOrderLineItem
        <DataMember> _
        Public ProductId As String

        <DataMember> _
        Public UnitCost As Single

        <DataMember> _
        Public Quantity As Integer

        Public Overrides Function ToString() As String
            Dim displayString As String = "Order LineItem: " & Quantity & " of " & ProductId & " @unit price: $" & UnitCost + Constants.vbLf
            Return displayString
        End Function

        Public ReadOnly Property TotalCost() As Single
            Get
                Return UnitCost * Quantity
            End Get
        End Property
    End Class

    ' Define the purchase order.
    <DataContract(Namespace:="http://Microsoft.ServiceModel.Samples")> _
    Public Class PurchaseOrder
        Private Shared ReadOnly OrderStates() As String = {"Pending", "Processed", "Shipped"}
        Private Shared statusIndexer As New Random(137)

        <DataMember> _
        Public PONumber As String

        <DataMember> _
        Public CustomerId As String

        <DataMember> _
        Public orderLineItems() As PurchaseOrderLineItem

        Public ReadOnly Property TotalCost() As Single
            Get
                Dim totalCost_Renamed As Single = 0
                For Each lineItem In orderLineItems
                    totalCost_Renamed += lineItem.TotalCost
                Next lineItem
                Return totalCost_Renamed
            End Get
        End Property

        Public ReadOnly Property Status() As String
            Get
                Return OrderStates(statusIndexer.Next(3))
            End Get
        End Property

        Public Overrides Function ToString() As String
            Dim strbuf As New System.Text.StringBuilder("Purchase Order: " & PONumber & Constants.vbLf)
            strbuf.Append(Constants.vbTab & "Customer: " & CustomerId & Constants.vbLf)
            strbuf.Append(Constants.vbTab & "OrderDetails" & Constants.vbLf)

            For Each lineItem In orderLineItems
                strbuf.Append(Constants.vbTab + Constants.vbTab + lineItem.ToString())
            Next lineItem

            strbuf.Append(Constants.vbTab & "Total cost of this order: $" & TotalCost + Constants.vbLf)
            strbuf.Append(Constants.vbTab & "Order status: " & Status + Constants.vbLf)
            Return strbuf.ToString()
        End Function
    End Class

    ' Order Processing Logic
    ' Can replace with transaction-aware resource such as SQL or transacted hashtable to hold the purchase orders.
    ' This example uses a non-transactional resource.
    Public Class Orders
        Private Shared purchaseOrders As New Dictionary(Of String, PurchaseOrder)()

        Public Shared Sub Add(ByVal po As PurchaseOrder)
            purchaseOrders.Add(po.PONumber, po)
        End Sub

        Public Shared Function GetOrderStatus(ByVal poNumber As String) As String
            Dim po As PurchaseOrder = Nothing
            If purchaseOrders.TryGetValue(poNumber, po) Then
                Return po.Status
            Else
                Return Nothing
            End If
        End Function

        Public Shared Sub DeleteOrder(ByVal poNumber As String)
            If purchaseOrders(poNumber) IsNot Nothing Then
                purchaseOrders.Remove(poNumber)
            End If
        End Sub
    End Class

    ' Define a service contract. 
    <ServiceContract(Namespace:="http://Microsoft.ServiceModel.Samples")> _
    Public Interface IOrderProcessor
        <OperationContract(IsOneWay:=True)> _
        Sub SubmitPurchaseOrder(ByVal po As PurchaseOrder)
    End Interface

    ' Service class that implements the service contract.
    ' Added code to write output to the console window.
    Public Class OrderProcessorService
        Implements IOrderProcessor
        <OperationBehavior(TransactionScopeRequired:=True, TransactionAutoComplete:=True)> _
        Public Sub SubmitPurchaseOrder(ByVal po As PurchaseOrder) Implements IOrderProcessor.SubmitPurchaseOrder
            Orders.Add(po)
            Console.WriteLine("Processing {0} ", po)
        End Sub
    End Class
End Namespace

// This is the hosting application.

using System;
using System.ServiceModel.Channels;
using System.Configuration;
using System.Messaging;
using System.ServiceModel;
using System.Transactions;
using System.Runtime.Serialization;
using System.Collections.Generic;

namespace Microsoft.ServiceModel.Samples
{
    class hostApp
    {
        // Host the service within this EXE console application.
        public static void Main()
        {
            // Get MSMQ queue name from appsettings in configuration.
            string queueName = ConfigurationManager.AppSettings["queueName"];

            // Create the transacted MSMQ queue if necessary.
            if (!MessageQueue.Exists(queueName))
                MessageQueue.Create(queueName, true);

            // Create a ServiceHost for the OrderProcessorService type.
            using (ServiceHost serviceHost = new ServiceHost(typeof(OrderProcessorService)))
            {
                // Open the ServiceHost to create listeners and start listening for messages.
                serviceHost.Open();

                // The service can now be accessed.
                Console.WriteLine("The service is ready.");
                Console.WriteLine("Press <ENTER> to terminate service.");
                Console.WriteLine();
                Console.ReadLine();

                // Close the ServiceHostB to shutdown the service.
                serviceHost.Close();
            }
        }
    }
}

' This is the hosting application.

Imports System.ServiceModel.Channels
Imports System.Configuration
Imports System.Messaging
Imports System.ServiceModel
Imports System.Transactions
Imports System.Runtime.Serialization
Imports System.Collections.Generic

Namespace Microsoft.ServiceModel.Samples
    Friend Class hostApp
        ' Host the service within this EXE console application.
        Public Shared Sub Main()
            ' Get MSMQ queue name from appsettings in configuration.
            Dim queueName As String = ConfigurationManager.AppSettings("queueName")

            ' Create the transacted MSMQ queue if necessary.
            If (Not MessageQueue.Exists(queueName)) Then
                MessageQueue.Create(queueName, True)
            End If

            ' Create a ServiceHost for the OrderProcessorService type.
            Using serviceHost As New ServiceHost(GetType(OrderProcessorService))
                ' Open the ServiceHost to create listeners and start listening for messages.
                serviceHost.Open()

                ' The service can now be accessed.
                Console.WriteLine("The service is ready.")
                Console.WriteLine("Press <ENTER> to terminate service.")
                Console.WriteLine()
                Console.ReadLine()

                ' Close the ServiceHostB to shutdown the service.
                serviceHost.Close()
            End Using
        End Sub
    End Class
End Namespace

// This is the client code.
//  Copyright (c) Microsoft Corporation.  All Rights Reserved.

using System;
using System.Configuration;
using System.Messaging;
using System.ServiceModel;
using System.Transactions;

namespace Microsoft.ServiceModel.Samples
{
    //The service contract is defined in generatedClient.cs, generated from the service by the svcutil tool.

    //Client implementation code.
    class Client
    {
        static void Main()
        {
            // Create a client.
            OrderProcessorClient client = new OrderProcessorClient();

            // Create the purchase order.
            PurchaseOrder po = new PurchaseOrder();
            po.CustomerId = "somecustomer.com";
            po.PONumber = Guid.NewGuid().ToString();

            PurchaseOrderLineItem lineItem1 = new PurchaseOrderLineItem();
            lineItem1.ProductId = "Blue Widget";
            lineItem1.Quantity = 54;
            lineItem1.UnitCost = 29.99F;

            PurchaseOrderLineItem lineItem2 = new PurchaseOrderLineItem();
            lineItem2.ProductId = "Red Widget";
            lineItem2.Quantity = 890;
            lineItem2.UnitCost = 45.89F;

            po.orderLineItems = new PurchaseOrderLineItem[2];
            po.orderLineItems[0] = lineItem1;
            po.orderLineItems[1] = lineItem2;

            //Create a transaction scope.
            using (TransactionScope scope = new TransactionScope(TransactionScopeOption.Required))
            {
                // Make a queued call to submit the purchase order.
                client.SubmitPurchaseOrder(po);
                // Complete the transaction.
                scope.Complete();
            }

            //Closing the client gracefully closes the connection and cleans up resources.
            client.Close();

            Console.WriteLine();
            Console.WriteLine("Press <ENTER> to terminate client.");
            Console.ReadLine();
        }
    }
}

' This is the client code.
'  Copyright (c) Microsoft Corporation.  All Rights Reserved.

Imports System.Configuration
Imports System.Messaging
Imports System.ServiceModel
Imports System.Transactions

Namespace Microsoft.ServiceModel.Samples
    'The service contract is defined in generatedClient.cs, generated from the service by the svcutil tool.

    'Client implementation code.
    Friend Class Client
        Shared Sub Main()
            ' Create a client.
            Dim client As New OrderProcessorClient()

            ' Create the purchase order.
            Dim po As New PurchaseOrder()
            po.CustomerId = "somecustomer.com"
            po.PONumber = Guid.NewGuid().ToString()

            Dim lineItem1 As New PurchaseOrderLineItem()
            lineItem1.ProductId = "Blue Widget"
            lineItem1.Quantity = 54
            lineItem1.UnitCost = 29.99F

            Dim lineItem2 As New PurchaseOrderLineItem()
            lineItem2.ProductId = "Red Widget"
            lineItem2.Quantity = 890
            lineItem2.UnitCost = 45.89F

            po.orderLineItems = New PurchaseOrderLineItem(1) {}
            po.orderLineItems(0) = lineItem1
            po.orderLineItems(1) = lineItem2

            'Create a transaction scope.
            Using scope As New TransactionScope(TransactionScopeOption.Required)
                ' Make a queued call to submit the purchase order.
                client.SubmitPurchaseOrder(po)
                ' Complete the transaction.
                scope.Complete()
            End Using

            'Closing the client gracefully closes the connection and cleans up resources.
            client.Close()

            Console.WriteLine()
            Console.WriteLine("Press <ENTER> to terminate client.")
            Console.ReadLine()
        End Sub
    End Class
End Namespace

Sdílet prostřednictvím

Postupy: Výměna zpráv zařazených do fronty pomocí koncových bodů WCF

Použití řazení front ve službě WCF

Vytvoření klienta pro službu ve frontě

Příklad

Viz také

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