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Procédure : créer un flux Atom de base

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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 Atom.

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 Atom10FeedFormatter.

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

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

    Notes

    Toutes les opérations du service qui appliquent 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 Guide pratique pour créer un service web HTTP WCF de base.

  2. Implémentez le contrat de service.

    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

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

    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")

  4. Créez plusieurs objets SyndicationItem.

    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)

  5. Ajoutez les objets SyndicationItem au flux.

    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

  6. Retournez le flux.

    return new Atom10FeedFormatter(feed);

    Return New Atom10FeedFormatter(feed)

Pour héberger le service

  1. Créez un objet WebServiceHost.

    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)

  2. Ouvrez l'hôte de service, chargez le flux à partir du service, affichez le flux et attendez que l'utilisateur appuie sur ENTRÉE.

    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()

Pour appeler GetBlog() avec un HTTP GET

  1. Dans un navigateur web, accédez à l’URL suivante : http://localhost:8000/BlogService/GetBlog

    L'URL contient l’adresse de base du service (http://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.

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

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

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

    SyndicationFeed feed = SyndicationFeed.Load(reader);

    Dim feed As SyndicationFeed = SyndicationFeed.Load(serviceAddress)

    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:");
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

Exemple

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

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

Compilation du code

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

Voir aussi