Procedura: scambiare messaggi in coda con endpoint WCF
Le code garantiscono una messaggistica affidabile tra un client e un servizio Windows Communication Foundation (WCF), anche se il servizio non è disponibile al momento della comunicazione. Nelle procedure seguenti viene spiegato come assicurare una comunicazione durevole tra un client e un servizio utilizzando l'associazione in coda standard in caso di implementazione del servizio WCF.
In questa sezione viene spiegato come utilizzare NetMsmqBinding per la comunicazione in coda tra un client WCF e un servizio WCF.
Per utilizzare l'accodamento in un servizio WCF
Definire un contratto di servizio utilizzando un'interfaccia contrassegnata con ServiceContractAttribute. Contrassegnare con OperationContractAttribute le operazioni che nell'interfaccia fanno parte del contratto di servizio e specificare che sono unidirezionali dal momento che non viene restituita alcuna risposta al metodo. Nel codice seguente sono contenuti un esempio di contratto di servizio semplice e la relativa definizione di operazione.
<ServiceContract(Namespace:="http://Microsoft.ServiceModel.Samples")> _ Public Interface IOrderProcessor <OperationContract(IsOneWay := True)> _ Sub SubmitPurchaseOrder(ByVal po As PurchaseOrder) End Interface
[ServiceContract(Namespace="http://Microsoft.ServiceModel.Samples")] public interface IOrderProcessor { [OperationContract(IsOneWay = true)] void SubmitPurchaseOrder(PurchaseOrder po); }
Quando il contratto di servizio passa tipi definiti dall'utente, è necessario definire contratti dati per tali tipi. Nel codice seguente vengono illustrati due contratti dati,
PurchaseOrder
ePurchaseOrderLineItem
. Questi due tipi definiscono i dati inviati al servizio. Si noti che le classi che definiscono questo contratto dati definiscono anche un certo numero di metodi. Questi non vengono considerati parte del contratto dati. Solo i membri che sono dichiarati con l'attributo DataMember fanno parte del contratto dati.<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
[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(); } }
Implementare i metodi del contratto di servizio definiti nell'interfaccia in una classe.
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
public class OrderProcessorService : IOrderProcessor { [OperationBehavior(TransactionScopeRequired = true, TransactionAutoComplete = true)] public void SubmitPurchaseOrder(PurchaseOrder po) { Orders.Add(po); Console.WriteLine("Processing {0} ", po); } }
Si noti OperationBehaviorAttribute sul metodo
SubmitPurchaseOrder
. In tal modo viene specificato che questa operazione deve essere chiamata all'interno di una transazione e che la transazione viene completata automaticamente quando il metodo è stato completato.Creare una coda transazionale utilizzando lo spazio dei nomi System.Messaging. È possibile scegliere di creare la coda mediante la console MMC (Microsoft Management Console) MSMQ. In tal caso, avere cura di creare una coda transazionale.
' Create the transacted MSMQ queue if necessary. If (Not MessageQueue.Exists(queueName)) Then MessageQueue.Create(queueName, True) End If
// Create the transacted MSMQ queue if necessary. if (!MessageQueue.Exists(queueName)) MessageQueue.Create(queueName, true);
Definire un ServiceEndpoint nella configurazione che specifichi l'indirizzo del servizio e utilizzi l'associazione NetMsmqBinding standard. Per ulteriori informazioni su utilizzo della configurazione di WCF, vedere Configuring Windows Communication Foundation Applications.
<services> <service name="Microsoft.ServiceModel.Samples.OrderProcessorService" behaviorConfiguration="CalculatorServiceBehavior"> <host> <baseAddresses> <add baseAddress="https://localhost:8000/ServiceModelSamples/service"/> </baseAddresses> </host> <!-- Define NetMsmqEndpoint --> <endpoint address="net.msmq://localhost/private/ServiceModelSamplesTransacted" binding="netMsmqBinding" contract="Microsoft.ServiceModel.Samples.IOrderProcessor" /> <!-- the mex endpoint is exposed at https://localhost:8000/ServiceModelSamples/service/mex --> <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" /> </service> </services>
Creare un host per il servizio
OrderProcessing
utilizzando l'elemento ServiceHost che legge i messaggi dalla coda e li elabora. Aprire l'host del servizio per rendere disponibile il servizio. Visualizzare un messaggio che indichi all'utente di premere un tasto qualsiasi per terminare il servizio. ChiamareReadLine
per attendere che il tasto venga premuto, quindi chiudere il servizio.' 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
// 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(); }
Per creare un client per il servizio in coda
Nell'esempio di codice riportato di seguito viene illustrato come eseguire l'applicazione host e utilizzare lo strumento Svcutil.exe per creare il client WCF.
svcutil https://localhost:8000/ServiceModelSamples/service
Definire un ServiceEndpoint nella configurazione che specifichi l'indirizzo e utilizzi l'associazione NetMsmqBinding standard, come illustrato nell'esempio seguente.
<client> <!-- Define NetMsmqEndpoint --> <endpoint address="net.msmq://localhost/private/ServiceModelSamplesTransacted" binding="netMsmqBinding" contract="Microsoft.ServiceModel.Samples.IOrderProcessor" /> </client>
Creare un ambito di transazione da scrivere nella coda transazionale, chiamare l'operazione
SubmitPurchaseOrder
e chiudere il client WCF, come illustrato nell'esempio seguente.'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()
//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();
Esempio
Negli esempi seguenti vengono illustrati il codice di servizio, l'applicazione host, il file App.config e il codice client inclusi per questo esempio.
' This is the service code
' Copyright (c) Microsoft Corporation. All Rights Reserved.
Imports System
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 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 hosting application.
Imports System
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 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 app.config for the service -->
<configuration>
<appSettings>
<!-- use appSetting to configure MSMQ queue name -->
<add key="queueName" value=".\private$\ServiceModelSamplesTransacted" />
</appSettings>
<system.serviceModel>
<services>
<service
name="Microsoft.ServiceModel.Samples.OrderProcessorService"
behaviorConfiguration="CalculatorServiceBehavior">
<host>
<baseAddresses>
<add baseAddress="https://localhost:8000/ServiceModelSamples/service"/>
</baseAddresses>
</host>
<!-- Define NetMsmqEndpoint -->
<endpoint address="net.msmq://localhost/private/ServiceModelSamplesTransacted"
binding="netMsmqBinding"
contract="Microsoft.ServiceModel.Samples.IOrderProcessor" />
<!-- the mex endpoint is exposed at https://localhost:8000/ServiceModelSamples/service/mex -->
<endpoint address="mex"
binding="mexHttpBinding"
contract="IMetadataExchange" />
</service>
</services>
<behaviors>
<serviceBehaviors>
<behavior name="CalculatorServiceBehavior">
<serviceMetadata httpGetEnabled="True"/>
</behavior>
</serviceBehaviors>
</behaviors>
</system.serviceModel>
</configuration>
' This is the client code.
' Copyright (c) Microsoft Corporation. All Rights Reserved.
Imports System
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
// 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 app.config for the client app -->
<configuration>
<system.serviceModel>
<client>
<!-- Define NetMsmqEndpoint -->
<endpoint address="net.msmq://localhost/private/ServiceModelSamplesTransacted"
binding="netMsmqBinding"
contract="Microsoft.ServiceModel.Samples.IOrderProcessor" />
</client>
</system.serviceModel>
</configuration>
Vedere anche
Attività
Associazioni MSMQ transazionali
Procedura: scambiare messaggi con endpoint WCF e con applicazioni del sistema di accodamento dei messaggi
Da Windows Communication Foundation a Accodamento messaggi
Accodamento messaggi in Windows Communication Foundation
Sicurezza dei messaggi nell'accodamento messaggi
Riferimento
Concetti
Accodamento in WCF
Installazione accodamento messaggi (MSMQ)