Comment : créer un flux RSS de base

Windows Communication Foundation (WCF) vous permet de créer un service qui expose un flux de syndication. Cette rubrique explique comment créer un service de syndication qui expose un flux de syndication RSS.

Pour créer un service de syndication de base

1. Définissez un contrat de service utilisant une interface marquée avec l'attribut WebGetAttribute. Chaque opération exposée comme un flux de syndication doit retourner un objet Rss20FeedFormatter.

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

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

   Remarque :
   Toutes les opérations du service qui appliquent l'attribut WebGetAttribute sont mappées aux demandes HTTP GET. Pour mapper votre opération à une méthode HTTP différente, utilisez WebInvokeAttribute à la place. Pour plus d'informations, consultez Procédure : créer un service Web HTTP WCF de base.

2. Implémentez le contrat de service.

   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("https://localhost/Content/One"), _
               "ItemOneID", _
               DateTime.Now)
   
           Dim item2 As SyndicationItem = New SyndicationItem( _
               "Item Two", _
               "This is the content for item two", _
               New Uri("https://localhost/Content/Two"), _
               "ItemTwoID", _
               DateTime.Now)
   
           Dim item3 As SyndicationItem = New SyndicationItem( _
               "Item Three", _
               "This is the content for item three", _
               New Uri("https://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
   

   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("https://localhost/Content/One"),
               "ItemOneID",
               DateTime.Now);
   
           SyndicationItem item2 = new SyndicationItem(
               "Item Two",
               "This is the content for item two",
               new Uri("https://localhost/Content/Two"),
               "ItemTwoID",
               DateTime.Now);
   
           SyndicationItem item3 = new SyndicationItem(
               "Item Three",
               "This is the content for item three",
               new Uri("https://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);
       }
   }
   

3. Créez un objet SyndicationFeed et ajoutez un auteur, une catégorie et une description.

   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")
   

   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");
   

4. Créez plusieurs objets SyndicationItem.

   Dim item1 As SyndicationItem = New SyndicationItem( _
       "Item One", _
       "This is the content for item one", _
       New Uri("https://localhost/Content/One"), _
       "ItemOneID", _
       DateTime.Now)
   
   Dim item2 As SyndicationItem = New SyndicationItem( _
       "Item Two", _
       "This is the content for item two", _
       New Uri("https://localhost/Content/Two"), _
       "ItemTwoID", _
       DateTime.Now)
   
   Dim item3 As SyndicationItem = New SyndicationItem( _
       "Item Three", _
       "This is the content for item three", _
       New Uri("https://localhost/Content/three"), _
       "ItemThreeID", _
       DateTime.Now)
   

   SyndicationItem item1 = new SyndicationItem(
       "Item One",
       "This is the content for item one",
       new Uri("https://localhost/Content/One"),
       "ItemOneID",
       DateTime.Now);
   
   SyndicationItem item2 = new SyndicationItem(
       "Item Two",
       "This is the content for item two",
       new Uri("https://localhost/Content/Two"),
       "ItemTwoID",
       DateTime.Now);
   
   SyndicationItem item3 = new SyndicationItem(
       "Item Three",
       "This is the content for item three",
       new Uri("https://localhost/Content/three"),
       "ItemThreeID",
       DateTime.Now);
   

5. Ajoutez le flux SyndicationItem.

   Dim items As New List(Of SyndicationItem)()
   
   items.Add(item1)
   items.Add(item2)
   items.Add(item3)
   
   feed.Items = items
   

   List<SyndicationItem> items = new List<SyndicationItem>();
   
   items.Add(item1);
   items.Add(item2);
   items.Add(item3);
   
   feed.Items = items;
   

6. Retournez le flux.

   Return New Rss20FeedFormatter(feed)
   

   return new Rss20FeedFormatter(feed);
   

Pour héberger un service

1. Créez un objet WebServiceHost.

   Dim baseAddress As New Uri("https://localhost:8000/BlogService")
   Dim svcHost As New WebServiceHost(GetType(BlogService), baseAddress)
   

   Uri baseAddress = new Uri("https://localhost:8000/BlogService");
   WebServiceHost svcHost = new WebServiceHost(typeof(BlogService), baseAddress);
   

2. Ouvrez l'hôte de service et attendez jusqu'à ce que l'utilisateur appuie sur ENTRÉE.

   svcHost.Open()
   Console.WriteLine("Service is running")
   
   Dim reader As XmlReader = XmlReader.Create("https://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()
   

   svcHost.Open();
   Console.WriteLine("Service is running");
   
   XmlReader reader = XmlReader.Create("https://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();
   

Pour appeler GetBlog() avec un HTTP GET

1. Ouvrez Internet Explorer, tapez l'URL suivante et appuyez sur ENTRÉE : https://localhost:8000/BlogService/GetBlog. L'URL contient l'adresse de base du service (https://localhost:8000/BlogService), l'adresse relative du point de terminaison et l'opération de service à appeler.

Pour appeler GetBlog() à partir d'un code

1. Créez un XmlReader avec l'adresse de base et la méthode que vous appelez.

   Dim serviceAddress As New Uri("https://localhost:8000/BlogService/GetBlog")
   

   Uri serviceAddress = new Uri("https://localhost:8000/BlogService/GetBlog");
   

2. Appelez la méthode Load statique, en passant dans le XmlReader que vous venez de créer.

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

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

   Cela appelle l'opération de service et remplit un nouvel objet SyndicationFeed avec le module de formatage retourné à partir de l'opération de service.

3. Accédez à l'objet de flux.

   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(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);
   }
   

Exemple

Les éléments suivants représentent l'intégralité du code pour cet exemple.

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("https://localhost/Content/One"), _
            "ItemOneID", _
            DateTime.Now)

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

        Dim item3 As SyndicationItem = New SyndicationItem( _
            "Item Three", _
            "This is the content for item three", _
            New Uri("https://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("https://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("https://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

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("https://localhost/Content/One"),
                "ItemOneID",
                DateTime.Now);

            SyndicationItem item2 = new SyndicationItem(
                "Item Two",
                "This is the content for item two",
                new Uri("https://localhost/Content/Two"),
                "ItemTwoID",
                DateTime.Now);

            SyndicationItem item3 = new SyndicationItem(
                "Item Three",
                "This is the content for item three",
                new Uri("https://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("https://localhost:8000/BlogService");
            WebServiceHost svcHost = new WebServiceHost(typeof(BlogService), baseAddress);

            try
            {
                svcHost.Open();
                Console.WriteLine("Service is running");

                XmlReader reader = XmlReader.Create("https://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();
            }
        }
    }
}

Compilation du code

Lors de la compilation du code précédent, référencez System.ServiceModel.dll et System.ServiceModel.Web.dll.

Voir aussi

Référence

WebHttpBinding
WebGetAttribute