Vorgehensweise: Erstellen eines grundlegenden RS-Feeds

Windows Communication Foundation (WCF) ermöglicht Ihnen die Erstellung eines Diensts, der einen Syndication-Feed verfügbar macht. In diesem Thema wird erläutert, wie ein Syndication-Dienst, der einen RSS Syndication-Feed verfügbar macht, erstellt wird.

So erstellen Sie einen grundlegenden Syndication-Dienst

1. Definieren Sie einen Dienstvertrag mit einer Schnittstelle, die mit dem WebGetAttribute-Attribut gekennzeichnet ist. Jeder Vorgang, der als Syndication-Feed verfügbar gemacht wird, sollte ein Rss20FeedFormatter-Objekt zurückgeben.

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

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

   Hinweis:
   Alle Dienstvorgänge, die das WebGetAttribute-Attribut übernehmen, werden HTTP GET-Anforderungen zugeordnet. Wenn Sie den Vorgang einer anderen HTTP-Methode zuordnen möchten, verwenden Sie stattdessen WebInvokeAttribute. Weitere Informationen finden Sie unter Vorgehensweise: Erstellen eines grundlegenden WCF-Web-HTTP-Diensts.

2. Implementieren Sie den Dienstvertrag.

   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. Erstellen Sie ein SyndicationFeed-Objekt, und fügen Sie einen Autor, eine Kategorie und eine Beschreibung hinzu.

   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. Erstellen Sie mehrere SyndicationItem-Objekte.

   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. Fügen Sie dem Feed das SyndicationItem hinzu

   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. Geben Sie den Feed zurück.

   Return New Rss20FeedFormatter(feed)
   

   return new Rss20FeedFormatter(feed);
   

So hosten Sie einen Dienst

1. Erstellen Sie ein WebServiceHost-Objekt.

   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. Öffnen Sie den Diensthost, und warten Sie, bis der Benutzer die EINGABETASTE drückt.

   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();
   

So rufen Sie GetBlog() mit HTTP GET auf

1. Öffnen Sie den Internet Explorer, geben Sie die folgende URL ein, und drücken Sie die EINGABETASTE: https://localhost:8000/BlogService/GetBlog Die URL enthält die Basisadresse des Diensts (https://localhost:8000/BlogService), die relative Adresse des Endpunkts und den aufzurufenden Dienstvorgang.

So rufen Sie GetBlog() aus dem Code auf

1. Erstellen Sie einen XmlReader mit der Basisadresse und der Methode, die Sie aufrufen.

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

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

2. Rufen Sie die statische Load-Methode auf, und übergeben Sie dabei den gerade erstellten XmlReader.

   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);
   
   

   Dies ruft einen Dienstvorgang auf und füllt einen neuen SyndicationFeed mit dem vom Dienstvorgang zurückgegebenen Formatierungsprogramm auf.

3. Greifen Sie auf das Feedobjekt zu.

   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);
   }
   

Beispiel

Nachfolgend ist die vollständige Codeauflistung für dieses Beispiel angegeben.

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();
            }
        }
    }
}

Kompilieren des Codes

Verweisen Sie beim Kompilieren des obigen Codes auf System.ServiceModel.dll und System.ServiceModel.Web.dll.

Siehe auch

Verweis

WebHttpBinding
WebGetAttribute