作法：建立基本 WCF Web HTTP 服務

發行項
03/08/2024

Windows Communication Foundation (WCF) 可讓您建立一個可公開 Web 端點的服務。 Web 端點會透過 XML 或 JSON 來傳送資料，而且不使用任何 SOAP 封套。本主題示範如何公開這類端點。

注意

保護 Web 端點的唯一方式，就是透過 HTTPS 運用傳輸安全性來加以公開。使用訊息安全性時，安全性資訊通常會放在 SOAP 標頭中，而傳送至非 SOAP 端點的訊息不包含任何 SOAP 封套，也就沒地方可以放置安全性資訊，因此您必須仰賴傳輸安全性。

若要建立 Web 端點

透過加上 ServiceContractAttribute、WebInvokeAttribute 和 WebGetAttribute 屬性標示的介面來定義服務合約。

[ServiceContract]
public interface IService
{
    [OperationContract]
    [WebGet]
    string EchoWithGet(string s);

    [OperationContract]
    [WebInvoke]
    string EchoWithPost(string s);
}

<ServiceContract()> _
Public Interface IService
    <OperationContract()> _
    <WebGet()> _
    Function EchoWithGet(ByVal s As String) As String

    <OperationContract()> _
    <WebInvoke()> _
    Function EchoWithPost(ByVal s As String) As String
end interface

注意

根據預設，WebInvokeAttribute 會將 POST 呼叫對應至作業。但是，您可以指定 "method=" 參數，以指定要對應至作業的 HTTP 方法 (例如，HEAD、PUT 和 DELETE)。 WebGetAttribute 沒有 "method=" 參數，只能將 GET 呼叫對應至服務作業。

實作服務合約。

public class Service : IService
{
    public string EchoWithGet(string s)
    {
        return "You said " + s;
    }

    public string EchoWithPost(string s)
    {
        return "You said " + s;
    }
}

Public Class Service
    Implements IService
    Public Function EchoWithGet(ByVal s As String) As String Implements IService.EchoWithGet
        Return "You said " + s
    End Function

    Public Function EchoWithPost(ByVal s As String) As String Implements IService.EchoWithPost
        Return "You said " + s
    End Function
End Class

若要裝載服務

建立 WebServiceHost 物件。

WebServiceHost host = new WebServiceHost(typeof(Service), new Uri("http://localhost:8000/"));

Dim host As WebServiceHost = New WebServiceHost(GetType(Service), New Uri("http://localhost:8000/"))

新增包含 ServiceEndpoint 的 WebHttpBehavior。
```
ServiceEndpoint ep = host.AddServiceEndpoint(typeof(IService), new WebHttpBinding(), "");
```
```
Dim ep As ServiceEndpoint = host.AddServiceEndpoint(GetType(IService), New WebHttpBinding(), "")
```
注意

如果您沒有加入端點，WebServiceHost 會自動建立預設端點。 WebServiceHost 也會加入 WebHttpBehavior，並停用 HTTP 說明網頁和 Web 服務描述語言 (WSDL) 的 GET 功能，使中繼資料端點不會干擾預設 HTTP 端點。

如果新增包含 "" 的 URL 非 SOAP 端點，會在嘗試呼叫端點上的作業時導致未預期的行為。發生原因是因為端點的接聽 URI 與說明頁面 (當您瀏覽至 WCF 服務的基底位址時所顯示的頁面) 的 URI 相同。

您可以執行下列其中一項動作來預防發生這種情況：
- 一律為非 SOAP 端點指定非空白的 URI。
- 關閉說明頁面。運用下列程式碼即可達到這個目的：
```
ServiceDebugBehavior sdb = host.Description.Behaviors.Find<ServiceDebugBehavior>();
sdb.HttpHelpPageEnabled = false;
```
```
Dim sdb As ServiceDebugBehavior = host.Description.Behaviors.Find(Of ServiceDebugBehavior)()
sdb.HttpHelpPageEnabled = False
```

開啟服務主機並等候使用者按下 ENTER。

host.Open();
Console.WriteLine("Service is running");
Console.WriteLine("Press enter to quit...");
Console.ReadLine();
host.Close();

host.Open()
Console.WriteLine("Service is running")
Console.WriteLine("Press enter to quit...")
Console.ReadLine()
host.Close()

此範例示範如何使用主控台應用程式來裝載 Web 樣式服務。您也可以透過 IIS 裝載這類服務。若要這麼做，請在 .svc 檔案中指定 WebServiceHostFactory 類別，如下列程式碼所示。

<%ServiceHost
    language=c#
    Debug="true"
    Service="Microsoft.Samples.Service"
    Factory=System.ServiceModel.Activation.WebServiceHostFactory%>

若要在瀏覽器中呼叫對應至 GET 的服務作業

開啟網頁瀏覽器，輸入 URL "http://localhost:8000/EchoWithGet?s=Hello, world!"，然後按 Enter。該 URL 包含服務的基底位址 (http://localhost:8000/)、端點的相對位址 ("")、要呼叫的服務作業 ("EchoWithGet")、問號，並於後面接續由連字號 (&) 分隔的具名參數清單。

若要透過程式碼呼叫服務作業

在 ChannelFactory<TChannel> 區塊中建立 using 的執行個體。

using (ChannelFactory<IService> cf = new ChannelFactory<IService>(new WebHttpBinding(), "http://localhost:8000"))

Using cf As New ChannelFactory(Of IService)(New WebHttpBinding(), "http://localhost:8000")

將 WebHttpBehavior 加入至 ChannelFactory<TChannel> 所呼叫的端點。

cf.Endpoint.Behaviors.Add(new WebHttpBehavior());

cf.Endpoint.Behaviors.Add(New WebHttpBehavior())

建立通道並呼叫服務。

IService channel = cf.CreateChannel();

string s;

Console.WriteLine("Calling EchoWithGet via HTTP GET: ");
s = channel.EchoWithGet("Hello, world");
Console.WriteLine("   Output: {0}", s);

Console.WriteLine("");
Console.WriteLine("This can also be accomplished by navigating to");
Console.WriteLine("http://localhost:8000/EchoWithGet?s=Hello, world!");
Console.WriteLine("in a web browser while this sample is running.");

Console.WriteLine("");

Console.WriteLine("Calling EchoWithPost via HTTP POST: ");
s = channel.EchoWithPost("Hello, world");
Console.WriteLine("   Output: {0}", s);

Dim channel As IService = cf.CreateChannel()

Dim s As String

Console.WriteLine("Calling EchoWithGet via HTTP GET: ")
s = channel.EchoWithGet("Hello, world")
Console.WriteLine("   Output: {0}", s)

Console.WriteLine("")
Console.WriteLine("This can also be accomplished by navigating to")
Console.WriteLine("http://localhost:8000/EchoWithGet?s=Hello, world!")
Console.WriteLine("in a web browser while this sample is running.")

Console.WriteLine("")

Console.WriteLine("Calling EchoWithPost via HTTP POST: ")
s = channel.EchoWithPost("Hello, world")
Console.WriteLine("   Output: {0}", s)

關閉 WebServiceHost。
```
host.Close();
```
```
host.Close()
```

範例

以下是這個範例的完整程式碼清單。

// Service.cs
using System;
using System.Collections.Generic;
using System.ServiceModel;
using System.ServiceModel.Description;
using System.ServiceModel.Web;
using System.Text;

namespace Microsoft.ServiceModel.Samples.BasicWebProgramming
{
    [ServiceContract]
    public interface IService
    {
        [OperationContract]
        [WebGet]
        string EchoWithGet(string s);

        [OperationContract]
        [WebInvoke]
        string EchoWithPost(string s);
    }
    public class Service : IService
    {
        public string EchoWithGet(string s)
        {
            return "You said " + s;
        }

        public string EchoWithPost(string s)
        {
            return "You said " + s;
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            WebServiceHost host = new WebServiceHost(typeof(Service), new Uri("http://localhost:8000/"));
            try
            {
                ServiceEndpoint ep = host.AddServiceEndpoint(typeof(IService), new WebHttpBinding(), "");
                host.Open();
                using (ChannelFactory<IService> cf = new ChannelFactory<IService>(new WebHttpBinding(), "http://localhost:8000"))
                {
                    cf.Endpoint.Behaviors.Add(new WebHttpBehavior());

                    IService channel = cf.CreateChannel();

                    string s;

                    Console.WriteLine("Calling EchoWithGet via HTTP GET: ");
                    s = channel.EchoWithGet("Hello, world");
                    Console.WriteLine("   Output: {0}", s);

                    Console.WriteLine("");
                    Console.WriteLine("This can also be accomplished by navigating to");
                    Console.WriteLine("http://localhost:8000/EchoWithGet?s=Hello, world!");
                    Console.WriteLine("in a web browser while this sample is running.");

                    Console.WriteLine("");

                    Console.WriteLine("Calling EchoWithPost via HTTP POST: ");
                    s = channel.EchoWithPost("Hello, world");
                    Console.WriteLine("   Output: {0}", s);
                    Console.WriteLine("");
                }

                Console.WriteLine("Press <ENTER> to terminate");
                Console.ReadLine();

                host.Close();
            }
            catch (CommunicationException cex)
            {
                Console.WriteLine("An exception occurred: {0}", cex.Message);
                host.Abort();
            }
        }
    }
}

'Service.cs
Imports System.Collections.Generic
Imports System.ServiceModel
Imports System.ServiceModel.Description
Imports System.ServiceModel.Web
Imports System.Text

<ServiceContract()> _
Public Interface IService
    <OperationContract()> _
    <WebGet()> _
    Function EchoWithGet(ByVal s As String) As String

    <OperationContract()> _
    <WebInvoke()> _
    Function EchoWithPost(ByVal s As String) As String
end interface

Public Class Service
    Implements IService
    Public Function EchoWithGet(ByVal s As String) As String Implements IService.EchoWithGet
        Return "You said " + s
    End Function

    Public Function EchoWithPost(ByVal s As String) As String Implements IService.EchoWithPost
        Return "You said " + s
    End Function
End Class

Module program

    Sub Main()
        Dim host As WebServiceHost = New WebServiceHost(GetType(Service), New Uri("http://localhost:8000/"))
        Try
            Dim ep As ServiceEndpoint = host.AddServiceEndpoint(GetType(IService), New WebHttpBinding(), "")
            host.Open()
            Using cf As New ChannelFactory(Of IService)(New WebHttpBinding(), "http://localhost:8000")

                cf.Endpoint.Behaviors.Add(New WebHttpBehavior())

                Dim channel As IService = cf.CreateChannel()

                Dim s As String

                Console.WriteLine("Calling EchoWithGet via HTTP GET: ")
                s = channel.EchoWithGet("Hello, world")
                Console.WriteLine("   Output: {0}", s)

                Console.WriteLine("")
                Console.WriteLine("This can also be accomplished by navigating to")
                Console.WriteLine("http://localhost:8000/EchoWithGet?s=Hello, world!")
                Console.WriteLine("in a web browser while this sample is running.")

                Console.WriteLine("")

                Console.WriteLine("Calling EchoWithPost via HTTP POST: ")
                s = channel.EchoWithPost("Hello, world")
                Console.WriteLine("   Output: {0}", s)
                Console.WriteLine("")
            End Using

            Console.WriteLine("Press <ENTER> to terminate")
            Console.ReadLine()

            host.Close()
        Catch cex As CommunicationException
            Console.WriteLine("An exception occurred: {0}", cex.Message)
            host.Abort()
        End Try
    End Sub

End Module

編譯程式碼

編譯 Service.cs 時，請參考 System.ServiceModel.dll 和 System.ServiceModel.Web.dll。