Windows Communication Foundation (WCF) consente di creare un servizio che espone un feed di diffusione. In questo argomento viene illustrato come creare un servizio di diffusione che espone un feed di diffusione Atom.
Per creare un servizio di diffusione di base
Definire un contratto di servizio usando un'interfaccia contrassegnata con l'attributo WebGetAttribute. Ogni operazione esposta come feed di diffusione deve restituire un oggetto Atom10FeedFormatter.
[ServiceContract]
public interface IBlog
{
[OperationContract]
[WebGet]
Atom10FeedFormatter GetBlog();
}
<ServiceContract()> _
Public Interface IBlog
<OperationContract()> _
<WebGet> _
Function GetBlog() As Atom10FeedFormatter
End Interface
public class BlogService : IBlog
{
public Atom10FeedFormatter GetBlog()
{
SyndicationFeed feed = new SyndicationFeed("My Blog Feed", "This is a test feed", new Uri("http://SomeURI"), "FeedOneID", new DateTimeOffset(DateTime.Now));
feed.Authors.Add(new SyndicationPerson("someone@microsoft.com"));
feed.Categories.Add(new SyndicationCategory("How To Sample Code"));
feed.Description = new TextSyndicationContent("This is a sample that illustrates how to expose a feed using ATOM with WCF");
SyndicationItem item1 = new SyndicationItem(
"Item One",
"This is the content for item one",
new Uri("http://localhost/Content/One"),
"ItemOneID",
DateTime.Now);
SyndicationItem item2 = new SyndicationItem(
"Item Two",
"This is the content for item two",
new Uri("http://localhost/Content/Two"),
"ItemTwoID",
DateTime.Now);
SyndicationItem item3 = new SyndicationItem(
"Item Three",
"This is the content for item three",
new Uri("http://localhost/Content/three"),
"ItemThreeID",
DateTime.Now);
List<SyndicationItem> items = new List<SyndicationItem>();
items.Add(item1);
items.Add(item2);
items.Add(item3);
feed.Items = items;
return new Atom10FeedFormatter(feed);
}
}
Public Class BlogService
Implements IBlog
Public Function GetBlog() As Atom10FeedFormatter Implements IBlog.GetBlog
Dim feed As New SyndicationFeed("My Blog Feed", "This is a test feed", New Uri("http://SomeURI"), "FeedOneID", new DateTimeOffset(DateTime.Now))
feed.Authors.Add(New SyndicationPerson("someone@microsoft.com"))
feed.Categories.Add(New SyndicationCategory("How To Sample Code"))
feed.Description = New TextSyndicationContent("This is a sample that illustrates how to expose a feed imports ATOM with WCF")
Dim item1 As New SyndicationItem( _
"Item One", _
"This is the content for item one", _
New Uri("http://localhost/Content/One"), _
"ItemOneID", _
DateTime.Now)
Dim item2 As New SyndicationItem( _
"Item Two", _
"This is the content for item two", _
New Uri("http://localhost/Content/Two"), _
"ItemTwoID", _
DateTime.Now)
Dim item3 As New SyndicationItem( _
"Item Three", _
"This is the content for item three", _
New Uri("http://localhost/Content/three"), _
"ItemThreeID", _
DateTime.Now)
Dim items As New List(Of SyndicationItem)()
items.Add(item1)
items.Add(item2)
items.Add(item3)
feed.Items = items
Return New Atom10FeedFormatter(feed)
End Function
End Class
Creare un oggetto SyndicationFeed e aggiungere un autore, una categoria e una descrizione.
SyndicationFeed feed = new SyndicationFeed("My Blog Feed", "This is a test feed", new Uri("http://SomeURI"), "FeedOneID", new DateTimeOffset(DateTime.Now));
feed.Authors.Add(new SyndicationPerson("someone@microsoft.com"));
feed.Categories.Add(new SyndicationCategory("How To Sample Code"));
feed.Description = new TextSyndicationContent("This is a sample that illustrates how to expose a feed using ATOM with WCF");
Dim feed As New SyndicationFeed("My Blog Feed", "This is a test feed", New Uri("http://SomeURI"), "FeedOneID", new DateTimeOffset(DateTime.Now))
feed.Authors.Add(New SyndicationPerson("someone@microsoft.com"))
feed.Categories.Add(New SyndicationCategory("How To Sample Code"))
feed.Description = New TextSyndicationContent("This is a sample that illustrates how to expose a feed imports ATOM with WCF")
SyndicationItem item1 = new SyndicationItem(
"Item One",
"This is the content for item one",
new Uri("http://localhost/Content/One"),
"ItemOneID",
DateTime.Now);
SyndicationItem item2 = new SyndicationItem(
"Item Two",
"This is the content for item two",
new Uri("http://localhost/Content/Two"),
"ItemTwoID",
DateTime.Now);
SyndicationItem item3 = new SyndicationItem(
"Item Three",
"This is the content for item three",
new Uri("http://localhost/Content/three"),
"ItemThreeID",
DateTime.Now);
Dim item1 As New SyndicationItem( _
"Item One", _
"This is the content for item one", _
New Uri("http://localhost/Content/One"), _
"ItemOneID", _
DateTime.Now)
Dim item2 As New SyndicationItem( _
"Item Two", _
"This is the content for item two", _
New Uri("http://localhost/Content/Two"), _
"ItemTwoID", _
DateTime.Now)
Dim item3 As New SyndicationItem( _
"Item Three", _
"This is the content for item three", _
New Uri("http://localhost/Content/three"), _
"ItemThreeID", _
DateTime.Now)
svcHost.Open()
Console.WriteLine("Service is running")
Dim reader As XmlReader = XmlReader.Create("http://localhost:8000/BlogService/GetBlog")
Dim feed As SyndicationFeed = SyndicationFeed.Load(reader)
Console.WriteLine(feed.Title.Text)
Console.WriteLine("Items:")
For Each item As SyndicationItem In feed.Items
Console.WriteLine("Title: {0}", item.Title.Text)
Console.WriteLine("Content: {0}", item.Title.Text)
Next
Console.WriteLine("Press <ENTER> to quit...")
Console.ReadLine()
svcHost.Close()
Per chiamare GetBlog() con un HTTP GET
In un browser web, navigare sull'URL seguente: http://localhost:8000/BlogService/GetBlog
L'URL contiene l'indirizzo di base del servizio (http://localhost:8000/BlogService), l'indirizzo relativo dell'endpoint e l'operazione del servizio da chiamare.
Per chiamare GetBlog() dal codice
Creare un XmlReader con l'indirizzo di base e il metodo che si sta chiamando.
Dim feed As SyndicationFeed = SyndicationFeed.Load(serviceAddress)
Verrà in tal modo richiamata l'operazione del servizio e verrà popolato un nuovo SyndicationFeed con il formattatore restituito dall'operazione del servizio.
Console.WriteLine(feed.Title.Text)
Console.WriteLine("Items:")
For Each item As SyndicationItem In feed.Items
Console.WriteLine("Title: {0}", item.Title.Text)
Console.WriteLine("Summary: {0}", item.Summary.Text)
Next
Esempio
Di seguito è riportato il codice completo per questo esempio.
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ServiceModel;
using System.Xml;
using System.ServiceModel.Description;
using System.ServiceModel.Syndication;
using System.ServiceModel.Channels;
using System.ServiceModel.Web;
namespace Service
{
[ServiceContract]
public interface IBlog
{
[OperationContract]
[WebGet]
Atom10FeedFormatter GetBlog();
}
public class BlogService : IBlog
{
public Atom10FeedFormatter GetBlog()
{
SyndicationFeed feed = new SyndicationFeed("My Blog Feed", "This is a test feed", new Uri("http://SomeURI"), "FeedOneID", new DateTimeOffset(DateTime.Now));
feed.Authors.Add(new SyndicationPerson("someone@microsoft.com"));
feed.Categories.Add(new SyndicationCategory("How To Sample Code"));
feed.Description = new TextSyndicationContent("This is a sample that illustrates how to expose a feed using ATOM with WCF");
SyndicationItem item1 = new SyndicationItem(
"Item One",
"This is the content for item one",
new Uri("http://localhost/Content/One"),
"ItemOneID",
DateTime.Now);
SyndicationItem item2 = new SyndicationItem(
"Item Two",
"This is the content for item two",
new Uri("http://localhost/Content/Two"),
"ItemTwoID",
DateTime.Now);
SyndicationItem item3 = new SyndicationItem(
"Item Three",
"This is the content for item three",
new Uri("http://localhost/Content/three"),
"ItemThreeID",
DateTime.Now);
List<SyndicationItem> items = new List<SyndicationItem>();
items.Add(item1);
items.Add(item2);
items.Add(item3);
feed.Items = items;
return new Atom10FeedFormatter(feed);
}
}
public class Host
{
static void Main(string[] args)
{
Uri baseAddress = new Uri("http://localhost:8000/BlogService/");
WebServiceHost svcHost = new WebServiceHost(typeof(BlogService), baseAddress);
try
{
svcHost.Open();
Console.WriteLine("Service is running");
XmlReader reader = XmlReader.Create("http://localhost:8000/BlogService/GetBlog");
SyndicationFeed feed = SyndicationFeed.Load(reader);
Console.WriteLine(feed.Title.Text);
Console.WriteLine("Items:");
foreach (SyndicationItem item in feed.Items)
{
Console.WriteLine("Title: {0}", item.Title.Text);
Console.WriteLine("Content: {0}", ((TextSyndicationContent)item.Content).Text);
}
Console.WriteLine("Press <ENTER> to quit...");
Console.ReadLine();
svcHost.Close();
}
catch (CommunicationException ce)
{
Console.WriteLine("An exception occurred: {0}", ce.Message);
svcHost.Abort();
}
}
}
}
Imports System.Xml
Imports System.Collections.Generic
Imports System.Collections.ObjectModel
Imports System.ServiceModel
Imports System.ServiceModel.Description
Imports System.ServiceModel.Syndication
Imports System.ServiceModel.Channels
Imports System.ServiceModel.Web
<ServiceContract()> _
Public Interface IBlog
<OperationContract()> _
<WebGet> _
Function GetBlog() As Atom10FeedFormatter
End Interface
Public Class BlogService
Implements IBlog
Public Function GetBlog() As Atom10FeedFormatter Implements IBlog.GetBlog
Dim feed As New SyndicationFeed("My Blog Feed", "This is a test feed", New Uri("http://SomeURI"), "FeedOneID", new DateTimeOffset(DateTime.Now))
feed.Authors.Add(New SyndicationPerson("someone@microsoft.com"))
feed.Categories.Add(New SyndicationCategory("How To Sample Code"))
feed.Description = New TextSyndicationContent("This is a sample that illustrates how to expose a feed imports ATOM with WCF")
Dim item1 As New SyndicationItem( _
"Item One", _
"This is the content for item one", _
New Uri("http://localhost/Content/One"), _
"ItemOneID", _
DateTime.Now)
Dim item2 As New SyndicationItem( _
"Item Two", _
"This is the content for item two", _
New Uri("http://localhost/Content/Two"), _
"ItemTwoID", _
DateTime.Now)
Dim item3 As New SyndicationItem( _
"Item Three", _
"This is the content for item three", _
New Uri("http://localhost/Content/three"), _
"ItemThreeID", _
DateTime.Now)
Dim items As New List(Of SyndicationItem)()
items.Add(item1)
items.Add(item2)
items.Add(item3)
feed.Items = items
Return New Atom10FeedFormatter(feed)
End Function
End Class
Module Program
Sub Main()
Dim baseAddress As New Uri("http://localhost:8000/BlogService/")
Dim svcHost As New WebServiceHost(GetType(BlogService), baseAddress)
Try
svcHost.AddServiceEndpoint(GetType(IBlog), New WebHttpBinding(), "")
svcHost.Open()
Console.WriteLine("Service is running")
Dim reader As XmlReader = XmlReader.Create("http://localhost:8000/BlogService/GetBlog")
Dim feed As SyndicationFeed = SyndicationFeed.Load(reader)
Console.WriteLine(feed.Title.Text)
Console.WriteLine("Items:")
For Each item As SyndicationItem In feed.Items
Console.WriteLine("Title: {0}", item.Title.Text)
Console.WriteLine("Content: {0}", item.Title.Text)
Next
Console.WriteLine("Press <ENTER> to quit...")
Console.ReadLine()
svcHost.Close()
Catch ce As CommunicationException
Console.WriteLine("An exception occurred: {0}", ce.Message)
svcHost.Abort()
End Try
End Sub
End Module
Compilazione del codice
Durante la compilazione del codice precedente, fare riferimento a System.ServiceModel.dll e a System.ServiceModel.Web.dll.
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