Procedura: creare un feed RSS di baseHow to: Create a Basic RSS Feed

Windows Communication Foundation (WCF) consente di creare un servizio che espone un feed di diffusione.Windows Communication Foundation (WCF) allows you to create a service that exposes a syndication feed. In questo argomento viene illustrato come creare un servizio di diffusione che espone un feed di diffusione RSS.This topic discusses how to create a syndication service that exposes an RSS syndication feed.

Per creare un servizio di diffusione di baseTo create a basic syndication service

  1. Definire un contratto di servizio usando un'interfaccia contrassegnata con l'attributo WebGetAttribute.Define a service contract using an interface marked with the WebGetAttribute attribute. Ogni operazione esposta come feed di diffusione deve restituire un oggetto Rss20FeedFormatter.Each operation that is exposed as a syndication feed should return a Rss20FeedFormatter object.

    [ServiceContract]
    public interface IBlog
    {
        [OperationContract]
        [WebGet]
        Rss20FeedFormatter GetBlog();
    }
    
    <ServiceContract()> _
    Public Interface IBlog
        <OperationContract()> _
    <WebGet> _
    Function GetBlog() As Rss20FeedFormatter
    End Interface
    

    Nota

    Tutte le operazioni del servizio che applicano l'attributo WebGetAttribute vengono mappate alle richieste HTTP GET.All service operations that apply the WebGetAttribute attribute are mapped to HTTP GET requests. Per eseguire il mapping dell'operazione a un metodo HTTP diverso, utilizzare invece WebInvokeAttribute.To map your operation to a different HTTP method, use the WebInvokeAttribute instead. Per altre informazioni, vedere procedura: creare un servizio HTTP Web di WCF base.For more information, see How to: Create a Basic WCF Web HTTP Service.

  2. Implementare il contratto di servizioImplement the service contract.

    public class BlogService : IBlog
    {
        public Rss20FeedFormatter GetBlog()
        {
            SyndicationFeed feed = new SyndicationFeed("My Blog Feed", "This is a test feed", new Uri("http://SomeURI"));
            feed.Authors.Add(new SyndicationPerson("someone@microsoft.com"));
            feed.Categories.Add(new SyndicationCategory("How To Sample Code"));
            feed.Description = new TextSyndicationContent("This is a how to sample that demonstrates how to expose a feed using RSS 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 Rss20FeedFormatter(feed);
        }
    }
    
    Public Class BlogService
        Implements IBlog
    
        Public Function GetBlog() As Rss20FeedFormatter Implements IBlog.GetBlog
            Dim feed As SyndicationFeed = New SyndicationFeed("My Blog Feed", "This is a test feed", New Uri("http://SomeURI"))
            feed.Authors.Add(New SyndicationPerson("someone@microsoft.com"))
            feed.Categories.Add(New SyndicationCategory("How To Sample Code"))
            feed.Description = New TextSyndicationContent("This is a how to sample that demonstrates how to expose a feed using RSS with WCF")
    
            Dim item1 As SyndicationItem = New SyndicationItem( _
                "Item One", _
                "This is the content for item one", _
                New Uri("http://localhost/Content/One"), _
                "ItemOneID", _
                DateTime.Now)
    
            Dim item2 As SyndicationItem = New SyndicationItem( _
                "Item Two", _
                "This is the content for item two", _
                New Uri("http://localhost/Content/Two"), _
                "ItemTwoID", _
                DateTime.Now)
    
            Dim item3 As SyndicationItem = 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 Rss20FeedFormatter(feed)
        End Function
    End Class
    
  3. Creare un oggetto SyndicationFeed e aggiungere un autore, una categoria e una descrizione.Create a SyndicationFeed object and add an author, category, and description.

    SyndicationFeed feed = new SyndicationFeed("My Blog Feed", "This is a test feed", new Uri("http://SomeURI"));
    feed.Authors.Add(new SyndicationPerson("someone@microsoft.com"));
    feed.Categories.Add(new SyndicationCategory("How To Sample Code"));
    feed.Description = new TextSyndicationContent("This is a how to sample that demonstrates how to expose a feed using RSS with WCF");
    
    Dim feed As SyndicationFeed = New SyndicationFeed("My Blog Feed", "This is a test feed", New Uri("http://SomeURI"))
    feed.Authors.Add(New SyndicationPerson("someone@microsoft.com"))
    feed.Categories.Add(New SyndicationCategory("How To Sample Code"))
    feed.Description = New TextSyndicationContent("This is a how to sample that demonstrates how to expose a feed using RSS with WCF")
    
  4. Creare diversi oggetti SyndicationItem.Create several SyndicationItem objects.

    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 SyndicationItem = New SyndicationItem( _
        "Item One", _
        "This is the content for item one", _
        New Uri("http://localhost/Content/One"), _
        "ItemOneID", _
        DateTime.Now)
    
    Dim item2 As SyndicationItem = New SyndicationItem( _
        "Item Two", _
        "This is the content for item two", _
        New Uri("http://localhost/Content/Two"), _
        "ItemTwoID", _
        DateTime.Now)
    
    Dim item3 As SyndicationItem = New SyndicationItem( _
        "Item Three", _
        "This is the content for item three", _
        New Uri("http://localhost/Content/three"), _
        "ItemThreeID", _
        DateTime.Now)
    
  5. Aggiungere SyndicationItem al feed.Add the SyndicationItem to the feed.

    List<SyndicationItem> items = new List<SyndicationItem>();
    
    items.Add(item1);
    items.Add(item2);
    items.Add(item3);
    
    feed.Items = items;
    
    Dim items As New List(Of SyndicationItem)()
    
    items.Add(item1)
    items.Add(item2)
    items.Add(item3)
    
    feed.Items = items
    
  6. Restituire il feed.Return the feed.

    return new Rss20FeedFormatter(feed);
    
    Return New Rss20FeedFormatter(feed)
    

Per ospitare un servizioTo host a service

  1. Creare un oggetto WebServiceHost.Create a WebServiceHost object.

    Uri baseAddress = new Uri("http://localhost:8000/BlogService");
    WebServiceHost svcHost = new WebServiceHost(typeof(BlogService), baseAddress);
    
    Dim baseAddress As New Uri("http://localhost:8000/BlogService")
    Dim svcHost As New WebServiceHost(GetType(BlogService), baseAddress)
    
  2. Aprire l'host del servizio e attendere finché l'utente non preme INVIO.Open the service host and wait until the user presses ENTER.

    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("Summary: {0}", ((TextSyndicationContent)item.Summary).Text);
    }
    Console.WriteLine("Press <enter> to quit...");
    Console.ReadLine();
    svcHost.Close();
    
    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("Summary: {0}", item.Summary.Text)
    Next
    Console.WriteLine("Press <enter> to quit...")
    Console.ReadLine()
    svcHost.Close()
    

Per chiamare GetBlog() con un HTTP GETTo call GetBlog() with an HTTP GET

  1. Aprire Internet Explorer, digitare l'URL seguente e premere INVIO: http://localhost:8000/BlogService/GetBlog.Open Internet Explorer, type the following URL, and press ENTER: 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 di servizio da chiamare.The URL contains the base address of the service (http://localhost:8000/BlogService), the relative address of the endpoint, and the service operation to call.

Per chiamare GetBlog() dal codiceTo call GetBlog() from code

  1. Creare un XmlReader con l'indirizzo di base e il metodo che si sta chiamando.Create an XmlReader with the base address and the method you are calling.

    Uri serviceAddress = new Uri("http://localhost:8000/BlogService/GetBlog");
    
    Dim serviceAddress As New Uri("http://localhost:8000/BlogService/GetBlog")
    
  2. Chiamare il metodo statico Load(XmlReader) passando l'oggetto XmlReader appena creato.Call the static Load(XmlReader) method, passing in the XmlReader you just created.

    XmlReader reader = XmlReader.Create("http://localhost:8000/BlogService/GetBlog");
    SyndicationFeed feed = SyndicationFeed.Load(reader);
        
    
    Dim reader As XmlReader = XmlReader.Create("http://localhost:8000/BlogService/GetBlog")
    Dim feed As SyndicationFeed = SyndicationFeed.Load(reader)
    

    Verrà in tal modo richiamata l'operazione del servizio e verrà popolato un nuovo SyndicationFeed con il formattatore restituito dall'operazione del servizio.This invokes the service operation and populates a new SyndicationFeed with the formatter returned from the service operation.

  3. Accedere all'oggetto feed.Access the feed object.

    Console.WriteLine(feed.Title.Text);
    Console.WriteLine("Items:");
    foreach (SyndicationItem item in feed.Items)
    {
        Console.WriteLine("Title: {0}", item.Title.Text);
        Console.WriteLine("Summary: {0}", ((TextSyndicationContent)item.Summary).Text);
    }
    
    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
    

EsempioExample

Di seguito è riportato il codice completo per questo esempio.The following is the full code listing for this example.

using System;
using System.Xml;
using System.ServiceModel;
using System.ServiceModel.Description;
using System.ServiceModel.Syndication;
using System.ServiceModel.Web;
using System.Collections.ObjectModel;
using System.Collections.Generic;

namespace Service
{
    [ServiceContract]
    public interface IBlog
    {
        [OperationContract]
        [WebGet]
        Rss20FeedFormatter GetBlog();
    }

    public class BlogService : IBlog
    {
        public Rss20FeedFormatter GetBlog()
        {
            SyndicationFeed feed = new SyndicationFeed("My Blog Feed", "This is a test feed", new Uri("http://SomeURI"));
            feed.Authors.Add(new SyndicationPerson("someone@microsoft.com"));
            feed.Categories.Add(new SyndicationCategory("How To Sample Code"));
            feed.Description = new TextSyndicationContent("This is a how to sample that demonstrates how to expose a feed using RSS 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 Rss20FeedFormatter(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("Summary: {0}", ((TextSyndicationContent)item.Summary).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
Imports System.Xml
Imports System.ServiceModel
Imports System.ServiceModel.Description
Imports System.ServiceModel.Syndication
Imports System.ServiceModel.Web
Imports System.Collections.ObjectModel
Imports System.Collections.Generic

<ServiceContract()> _
Public Interface IBlog
    <OperationContract()> _
<WebGet> _
Function GetBlog() As Rss20FeedFormatter
End Interface

Public Class BlogService
    Implements IBlog

    Public Function GetBlog() As Rss20FeedFormatter Implements IBlog.GetBlog
        Dim feed As SyndicationFeed = New SyndicationFeed("My Blog Feed", "This is a test feed", New Uri("http://SomeURI"))
        feed.Authors.Add(New SyndicationPerson("someone@microsoft.com"))
        feed.Categories.Add(New SyndicationCategory("How To Sample Code"))
        feed.Description = New TextSyndicationContent("This is a how to sample that demonstrates how to expose a feed using RSS with WCF")

        Dim item1 As SyndicationItem = New SyndicationItem( _
            "Item One", _
            "This is the content for item one", _
            New Uri("http://localhost/Content/One"), _
            "ItemOneID", _
            DateTime.Now)

        Dim item2 As SyndicationItem = New SyndicationItem( _
            "Item Two", _
            "This is the content for item two", _
            New Uri("http://localhost/Content/Two"), _
            "ItemTwoID", _
            DateTime.Now)

        Dim item3 As SyndicationItem = 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 Rss20FeedFormatter(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.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("Summary: {0}", item.Summary.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 codiceCompiling the Code

Durante la compilazione del codice precedente, fare riferimento a System.ServiceModel.dll e a System.ServiceModel.Web.dll.When compiling the preceding code, reference System.ServiceModel.dll and System.ServiceModel.Web.dll.

Vedere ancheSee Also

WebHttpBinding
WebGetAttribute