HOW TO：建立基本 RSS 摘要

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02/28/2011

Windows Communication Foundation (WCF) 可以讓您建立公開新聞訂閱摘要的服務。本主題討論如何建立可公開 RSS 新聞訂閱摘要的新聞訂閱服務。

若要建立基本新聞訂閱服務

使用以 WebGetAttribute 屬性標記的介面來定義服務合約。每個公開為新聞訂閱摘要的作業都應該傳回 Rss20FeedFormatter 物件。

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

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

注意：
所有套用 WebGetAttribute 屬性的服務作業都會對應至 HTTP GET 要求。若要將您的作業對應至不同的 HTTP 方法，請改用 WebInvokeAttribute。如需詳細資訊，請參閱 HOW TO：建立基本 WCF Web HTTP 服務.

實作服務合約。

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);
    }
}

建立 SyndicationFeed 物件並加入作者、分類和描述。

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");

建立幾個 SyndicationItem 物件。

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);

將 SyndicationItem 加入至摘要。

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;

傳回摘要。

Return New Rss20FeedFormatter(feed)

return new Rss20FeedFormatter(feed);

若要裝載服務

建立 WebServiceHost 物件。

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);

開啟服務主機並等候使用者按下 ENTER。

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();

若要使用 HTTP GET 呼叫 GetBlog()

開啟 Internet Explorer 並輸入下列 URL，然後按下 ENTER：https://localhost:8000/BlogService/GetBlog。URL 包含服務的基底位址 (https://localhost:8000/BlogService)、端點的相對位址，以及要呼叫的服務作業。

若要從程式碼呼叫 GetBlog()

使用基底位址與您要呼叫的方法建立 XmlReader。

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

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

呼叫靜態 Load 方法，傳入剛才建立的 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);

這會叫用服務作業，並在新的 SyndicationFeed 中填入服務作業所傳回的格式器。

存取摘要物件。

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);
}

範例

以下是這個範例的完整程式碼清單。

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();
            }
        }
    }
}

編譯程式碼

在編譯先前的程式碼時，請參考 System.ServiceModel.dll 和 System.ServiceModel.Web.dll。

另請參閱

參考

WebHttpBinding
WebGetAttribute

共用方式為