方法 : 基本的な RSS フィードを作成する

Windows Communication Foundation (WCF) では、配信フィードを公開するサービスを作成できます。ここでは、RSS 配信フィードを公開する配信サービスを作成する方法について説明します。

基本的な配信サービスを作成するには

1. WebGetAttribute 属性でマークされたインターフェイスを使用して、サービス コントラクトを定義します。配信フィードとして公開される各操作は、Rss20FeedFormatter オブジェクトを返す必要があります。

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

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

   注 :
   WebGetAttribute 属性を適用するすべてのサービス操作は、HTTP GET 要求にマッピングされます。他の HTTP メソッドに操作をマッピングするには、代わりに WebInvokeAttribute を使用します。詳細については、次のトピックを参照してください。、「方法 : 基本的な WCF Web HTTP サービスを作成する」を参照してください。

2. サービス コントラクトを実装します。

   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. SyndicationFeed オブジェクトを作成し、作成者、カテゴリ、および説明を追加します。

   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. 複数の SyndicationItem オブジェクトを作成します。

   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. SyndicationItem をフィードに追加します。

   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. フィードを返します。

   Return New Rss20FeedFormatter(feed)
   

   return new Rss20FeedFormatter(feed);
   

サービスをホストするには

1. WebServiceHost オブジェクトを作成します。

   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. サービス ホストを開き、ユーザーが Enter キーを押すのを待ちます。

   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();
   

HTTP GET で GetBlog() を呼び出すには

1. Internet Explorer を開いて「https://localhost:8000/BlogService/GetBlog」という URL を入力し、Enter キーを押します。この URL には、サービスのベース アドレス (https://localhost:8000/BlogService)、エンドポイントの相対アドレス、および呼び出すサービス操作が含まれます。

コードから GetBlog() を呼び出すには

1. ベース アドレスと呼び出すメソッドを使用して XmlReader を作成します。

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

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

2. 静的な Load メソッドを呼び出し、作成した XmlReader を渡します。

   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);
   
   

   これにより、サービス操作が呼び出され、サービス操作から返されたフォーマッタが新しい SyndicationFeed に設定されます。

3. フィード オブジェクトにアクセスします。

   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);
   }
   

例

この例の完全なコードの一覧を以下に示します。

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();
            }
        }
    }
}

コードのコンパイル方法

上記のコードのコンパイル時には、System.ServiceModel.dll と System.ServiceModel.Web.dll が参照されます。

参照

リファレンス

WebHttpBinding
WebGetAttribute