Procedure: Een basis atomfeed maken

Artikel
03/05/2024

Met Windows Communication Foundation (WCF) kunt u een service maken die een syndicatiefeed beschikbaar maakt. In dit onderwerp wordt beschreven hoe u een syndicatieservice maakt die een Atom-syndicatiefeed beschikbaar maakt.

Een eenvoudige syndicatieservice maken

Definieer een servicecontract met behulp van een interface die is gemarkeerd met het WebGetAttribute kenmerk. Elke bewerking die wordt weergegeven als een syndicatiefeed, moet een Atom10FeedFormatter object retourneren.
```
[ServiceContract]
public interface IBlog
{
    [OperationContract]
    [WebGet]
    Atom10FeedFormatter GetBlog();
}
```
```
<ServiceContract()> _
Public Interface IBlog
    <OperationContract()> _
    <WebGet> _
    Function GetBlog() As Atom10FeedFormatter
End Interface
```
Notitie

Alle servicebewerkingen die van WebGetAttribute toepassing zijn, worden toegewezen aan HTTP GET-aanvragen. Als u uw bewerking wilt toewijzen aan een andere HTTP-methode, gebruikt u in plaats daarvan de WebInvokeAttribute methode. Zie How to: Create a Basic WCF Web HTTP Service(s) voor meer informatie.

Implementeer het servicecontract.

public class BlogService : IBlog
{
    public Atom10FeedFormatter GetBlog()
    {
        SyndicationFeed feed = new SyndicationFeed("My Blog Feed", "This is a test feed", new Uri("http://SomeURI"), "FeedOneID", new DateTimeOffset(DateTime.Now));
        feed.Authors.Add(new SyndicationPerson("someone@microsoft.com"));
        feed.Categories.Add(new SyndicationCategory("How To Sample Code"));
        feed.Description = new TextSyndicationContent("This is a sample that illustrates how to expose a feed using ATOM 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 Atom10FeedFormatter(feed);
    }
}

Public Class BlogService
    Implements IBlog
    Public Function GetBlog() As Atom10FeedFormatter Implements IBlog.GetBlog
        Dim feed As New SyndicationFeed("My Blog Feed", "This is a test feed", New Uri("http://SomeURI"), "FeedOneID", new DateTimeOffset(DateTime.Now))
        feed.Authors.Add(New SyndicationPerson("someone@microsoft.com"))
        feed.Categories.Add(New SyndicationCategory("How To Sample Code"))
        feed.Description = New TextSyndicationContent("This is a sample that illustrates how to expose a feed imports ATOM with WCF")

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

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

        Dim item3 As 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 Atom10FeedFormatter(feed)
    End Function
End Class

Maak een SyndicationFeed object en voeg een auteur, categorie en beschrijving toe.

SyndicationFeed feed = new SyndicationFeed("My Blog Feed", "This is a test feed", new Uri("http://SomeURI"), "FeedOneID", new DateTimeOffset(DateTime.Now));
feed.Authors.Add(new SyndicationPerson("someone@microsoft.com"));
feed.Categories.Add(new SyndicationCategory("How To Sample Code"));
feed.Description = new TextSyndicationContent("This is a sample that illustrates how to expose a feed using ATOM with WCF");

Dim feed As New SyndicationFeed("My Blog Feed", "This is a test feed", New Uri("http://SomeURI"), "FeedOneID", new DateTimeOffset(DateTime.Now))
feed.Authors.Add(New SyndicationPerson("someone@microsoft.com"))
feed.Categories.Add(New SyndicationCategory("How To Sample Code"))
feed.Description = New TextSyndicationContent("This is a sample that illustrates how to expose a feed imports ATOM with WCF")

Maak verschillende SyndicationItem objecten.

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

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

Dim item3 As New SyndicationItem( _
    "Item Three", _
    "This is the content for item three", _
    New Uri("http://localhost/Content/three"), _
    "ItemThreeID", _
    DateTime.Now)

Voeg de SyndicationItem objecten toe aan de 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

Retourneer de feed.

return new Atom10FeedFormatter(feed);

Return New Atom10FeedFormatter(feed)

De service hosten

Maak een 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)

Open de servicehost, laad de feed van de service, geef de feed weer en wacht tot de gebruiker op Enter drukt.

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("Content: {0}", ((TextSyndicationContent)item.Content).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("Content: {0}", item.Title.Text)
Next

Console.WriteLine("Press <ENTER> to quit...")
Console.ReadLine()
svcHost.Close()

GetBlog() aanroepen met een HTTP GET

Blader in een webbrowser naar de volgende URL: http://localhost:8000/BlogService/GetBlog

De URL bevat het basisadres van de service (http://localhost:8000/BlogService), het relatieve adres van het eindpunt en de servicebewerking die moet worden aangeroepen.

GetBlog() aanroepen vanuit code

Maak een XmlReader met het basisadres en de methode die u aanroept.

XmlReader reader = XmlReader.Create("http://localhost:8000/BlogService/GetBlog");

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

Roep de statische Load(XmlReader) methode aan, waarbij de XmlReader zojuist gemaakte methode wordt doorgegeven.
```
SyndicationFeed feed = SyndicationFeed.Load(reader);
```
```
Dim feed As SyndicationFeed = SyndicationFeed.Load(serviceAddress)
```
Hiermee wordt de servicebewerking aangeroepen en wordt een nieuwe SyndicationFeed gevuld met de formatter die wordt geretourneerd door de servicebewerking.

Toegang tot het feedobject.

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

Opmerking

Hier volgt de volledige codevermelding voor dit voorbeeld.

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

namespace Service
{
    [ServiceContract]
    public interface IBlog
    {
        [OperationContract]
        [WebGet]
        Atom10FeedFormatter GetBlog();
    }

    public class BlogService : IBlog
    {
        public Atom10FeedFormatter GetBlog()
        {
            SyndicationFeed feed = new SyndicationFeed("My Blog Feed", "This is a test feed", new Uri("http://SomeURI"), "FeedOneID", new DateTimeOffset(DateTime.Now));
            feed.Authors.Add(new SyndicationPerson("someone@microsoft.com"));
            feed.Categories.Add(new SyndicationCategory("How To Sample Code"));
            feed.Description = new TextSyndicationContent("This is a sample that illustrates how to expose a feed using ATOM 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 Atom10FeedFormatter(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("Content: {0}", ((TextSyndicationContent)item.Content).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.Xml
Imports System.Collections.Generic
Imports System.Collections.ObjectModel
Imports System.ServiceModel
Imports System.ServiceModel.Description
Imports System.ServiceModel.Syndication
Imports System.ServiceModel.Channels
Imports System.ServiceModel.Web

<ServiceContract()> _
Public Interface IBlog
    <OperationContract()> _
    <WebGet> _
    Function GetBlog() As Atom10FeedFormatter
End Interface

Public Class BlogService
    Implements IBlog
    Public Function GetBlog() As Atom10FeedFormatter Implements IBlog.GetBlog
        Dim feed As New SyndicationFeed("My Blog Feed", "This is a test feed", New Uri("http://SomeURI"), "FeedOneID", new DateTimeOffset(DateTime.Now))
        feed.Authors.Add(New SyndicationPerson("someone@microsoft.com"))
        feed.Categories.Add(New SyndicationCategory("How To Sample Code"))
        feed.Description = New TextSyndicationContent("This is a sample that illustrates how to expose a feed imports ATOM with WCF")

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

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

        Dim item3 As 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 Atom10FeedFormatter(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.AddServiceEndpoint(GetType(IBlog), New WebHttpBinding(), "")
            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("Content: {0}", item.Title.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

De code compileren

Bij het compileren van de voorgaande code verwijst u naar System.ServiceModel.dll en System.ServiceModel.Web.dll.

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