C# 在WCF REST 4中,是否可以将HTML作为响应格式之一返回

C# 在WCF REST 4中,是否可以将HTML作为响应格式之一返回,c#,wcf,rest,C#,Wcf,Rest,我有一个我正在编写的服务,打算由多个调用方使用,包括那些无法接收或解析XML或JSON的调用方 我知道可以使用原始流从服务响应返回HTML,但我希望能够根据客户端传递的Accepts类型头返回XML、JSON或HTML中的一种 我可以用单独的URL来实现,但这将取代一个已经有一个定义良好的API层的系统 是否有这样做的例子,或者是否有人知道管道的哪些部分需要延长 (附录):我已经知道自动格式选择并启用了它,但我想从一个端点支持所有三种(或更多)格式(HTML、JSON、XML等)。是的,这是可能

我有一个我正在编写的服务,打算由多个调用方使用,包括那些无法接收或解析XML或JSON的调用方

我知道可以使用原始流从服务响应返回HTML,但我希望能够根据客户端传递的Accepts类型头返回XML、JSON或HTML中的一种

我可以用单独的URL来实现,但这将取代一个已经有一个定义良好的API层的系统

是否有这样做的例子,或者是否有人知道管道的哪些部分需要延长


(附录):我已经知道自动格式选择并启用了它,但我想从一个端点支持所有三种(或更多)格式(HTML、JSON、XML等)。

是的,这是可能的。但是您需要创建一个新的消息格式化程序,它知道如何在CLR类型(操作响应)和HTML页面之间进行转换。最简单的方法是将原始格式化程序包装到一个新的格式化程序中,这样当您收到对
Accept:text/html
请求的响应时,您就可以使用您的逻辑,但对于其他请求,您就可以使用原始格式化程序

不过,格式化程序无法访问传入的请求,因此我们也可以使用消息检查器来提供这一功能

下面的代码显示了这种格式化程序/检查器对的一种可能实现

public class StackOverflow_10519075
{
    [DataContract(Name = "Person", Namespace = "")]
    public class Person
    {
        [DataMember]
        public string Name { get; set; }
        [DataMember]
        public int Age { get; set; }
    }
    [ServiceContract]
    public interface ITest
    {
        [WebGet]
        Person GetPerson();
    }
    public class Service : ITest
    {
        public Person GetPerson()
        {
            return new Person { Name = "John Doe", Age = 33 };
        }
    }
    public class MyHtmlAwareFormatter : IDispatchMessageFormatter
    {
        IDispatchMessageFormatter original;
        public MyHtmlAwareFormatter(IDispatchMessageFormatter original)
        {
            this.original = original;
        }

        public void DeserializeRequest(Message message, object[] parameters)
        {
            this.original.DeserializeRequest(message, parameters);
        }

        public Message SerializeReply(MessageVersion messageVersion, object[] parameters, object result)
        {
            MyUseHtmlExtension useHtml = OperationContext.Current.Extensions.Find<MyUseHtmlExtension>();
            if (useHtml != null && useHtml.UseHtmlResponse)
            {
                StringBuilder sb = new StringBuilder();
                sb.AppendLine("<html><head><title>Result of " + useHtml.OperationName + "</title></head>");
                sb.AppendLine("<body><h1>Result of " + useHtml.OperationName + "</h1>");
                sb.AppendLine("<p><b>" + result.GetType().FullName + "</b></p>");
                sb.AppendLine("<ul>");
                foreach (var prop in result.GetType().GetProperties())
                {
                    string line = string.Format("{0}: {1}", prop.Name, prop.GetValue(result, null));
                    sb.AppendLine("<li>" + line + "</li>");
                }
                sb.AppendLine("</ul></body></html>");
                byte[] bytes = Encoding.UTF8.GetBytes(sb.ToString());
                Message reply = Message.CreateMessage(messageVersion, null, new RawBodyWriter(bytes));
                reply.Properties.Add(WebBodyFormatMessageProperty.Name, new WebBodyFormatMessageProperty(WebContentFormat.Raw));
                HttpResponseMessageProperty httpResp = new HttpResponseMessageProperty();
                reply.Properties.Add(HttpResponseMessageProperty.Name, httpResp);
                httpResp.Headers[HttpResponseHeader.ContentType] = "text/html";
                return reply;
            }
            else
            {
                return original.SerializeReply(messageVersion, parameters, result);
            }
        }

        class RawBodyWriter : BodyWriter
        {
            private byte[] bytes;

            public RawBodyWriter(byte[] bytes)
                : base(true)
            {
                this.bytes = bytes;
            }

            protected override void OnWriteBodyContents(XmlDictionaryWriter writer)
            {
                writer.WriteStartElement("Binary");
                writer.WriteBase64(this.bytes, 0, this.bytes.Length);
                writer.WriteEndElement();
            }
        }
    }
    public class MyHtmlAwareInspector : IDispatchMessageInspector
    {
        public object AfterReceiveRequest(ref Message request, IClientChannel channel, InstanceContext instanceContext)
        {
            HttpRequestMessageProperty httpRequest = (HttpRequestMessageProperty)request.Properties[HttpRequestMessageProperty.Name];
            string accept = httpRequest.Headers[HttpRequestHeader.Accept];
            string operationName = request.Properties[WebHttpDispatchOperationSelector.HttpOperationNamePropertyName] as string;
            if (accept == "text/html")
            {
                OperationContext.Current.Extensions.Add(new MyUseHtmlExtension { UseHtmlResponse = true, OperationName = operationName });
            }

            return null;
        }

        public void BeforeSendReply(ref Message reply, object correlationState)
        {
        }
    }
    class MyUseHtmlExtension : IExtension<OperationContext>
    {
        public void Attach(OperationContext owner) { }
        public void Detach(OperationContext owner) { }
        public bool UseHtmlResponse { get; set; }
        public string OperationName { get; set; }
    }
    public class MyHtmlAwareEndpointBehavior : IEndpointBehavior
    {
        public void AddBindingParameters(ServiceEndpoint endpoint, BindingParameterCollection bindingParameters)
        {
        }

        public void ApplyClientBehavior(ServiceEndpoint endpoint, ClientRuntime clientRuntime)
        {
        }

        public void ApplyDispatchBehavior(ServiceEndpoint endpoint, EndpointDispatcher endpointDispatcher)
        {
            endpointDispatcher.DispatchRuntime.MessageInspectors.Add(new MyHtmlAwareInspector());
            foreach (DispatchOperation operation in endpointDispatcher.DispatchRuntime.Operations)
            {
                operation.Formatter = new MyHtmlAwareFormatter(operation.Formatter);
            }
        }

        public void Validate(ServiceEndpoint endpoint)
        {
        }
    }
    public static void Test()
    {
        string baseAddress = "http://" + Environment.MachineName + ":8000/Service";
        ServiceHost host = new ServiceHost(typeof(Service), new Uri(baseAddress));
        var endpoint = host.AddServiceEndpoint(typeof(ITest), new WebHttpBinding(), "");
        endpoint.Behaviors.Add(new WebHttpBehavior { AutomaticFormatSelectionEnabled = true });
        endpoint.Behaviors.Add(new MyHtmlAwareEndpointBehavior());
        host.Open();
        Console.WriteLine("Host opened");

        WebClient c;

        c = new WebClient();
        c.Headers[HttpRequestHeader.Accept] = "application/json";
        Console.WriteLine(c.DownloadString(baseAddress + "/GetPerson"));
        Console.WriteLine();

        c = new WebClient();
        c.Headers[HttpRequestHeader.Accept] = "text/xml";
        Console.WriteLine(c.DownloadString(baseAddress + "/GetPerson"));
        Console.WriteLine();

        c = new WebClient();
        c.Headers[HttpRequestHeader.Accept] = "text/html";
        Console.WriteLine(c.DownloadString(baseAddress + "/GetPerson"));
        Console.WriteLine();

        Console.Write("Press ENTER to close the host");
        Console.ReadLine();
        host.Close();
    }
}
公共类StackOverflow_10519075
{
[DataContract(Name=“Person”,Namespace=”“)]
公共阶层人士
{
[数据成员]
公共字符串名称{get;set;}
[数据成员]
公共整数{get;set;}
}
[服务合同]
公共接口测试
{
[WebGet]
Person GetPerson();
}
公共类服务:ITest
{
公众人物
{
返回新人{Name=“John Doe”,年龄=33};
}
}
公共类MyHtmlLaWareFormatter:IDispatchMessageFormatter
{
IDispatchMessageFormatter原件;
公共MyHtmlLaWareFormatter(IDispatchMessageFormatter原件)
{
this.original=原件;
}
public void反序列化请求(消息,对象[]参数)
{
this.original.DeserializeRequest(消息、参数);
}
公共消息序列化回复(MessageVersion MessageVersion,对象[]参数,对象结果)
{
MyUseHtmlExtension-useHtml=OperationContext.Current.Extensions.Find();
if(useHtml!=null&&useHtml.UseHtmlResponse)
{
StringBuilder sb=新的StringBuilder();
sb.AppendLine(“结果“+useHtml.OperationName+”);
sb.AppendLine(“结果“+useHtml.OperationName+”);
sb.AppendLine(“”+result.GetType().FullName+”

”); sb.附录(“
    ”); foreach(result.GetType().GetProperties()中的var prop) { string line=string.Format(“{0}:{1}”,prop.Name,prop.GetValue(result,null)); sb.追加行(“
  • ”+行+“
  • ”); } sb.附录(“
”); byte[]bytes=Encoding.UTF8.GetBytes(sb.ToString()); Message reply=Message.CreateMessage(messageVersion,null,新的RawBodyWriter(字节)); Add(WebBodyFormatMessageProperty.Name,新的WebBodyFormatMessageProperty(WebContentFormat.Raw)); HttpResponseMessageProperty httpResp=新的HttpResponseMessageProperty(); reply.Properties.Add(HttpResponseMessageProperty.Name,httpResp); httpResp.Headers[HttpResponseHeader.ContentType]=“text/html”; 回复; } 其他的 { 返回原始.SerializeReply(messageVersion、参数、结果); } } 类别:BodyWriter { 专用字节[]字节; 公共RawBodyWriter(字节[]字节) :base(真) { this.bytes=字节; } 受保护的重写无效OnWriteByContents(XmlDictionaryWriter编写器) { writer.writeStarteElement(“二进制”); writer.WriteBase64(this.bytes,0,this.bytes.Length); writer.writeedelement(); } } } 公共类MyHtmlAwareInspector:IDispatchMessageInspector { 接收请求后的公共对象(ref消息请求、IClientChannel通道、InstanceContext InstanceContext) { HttpRequestMessageProperty httpRequest=(HttpRequestMessageProperty)request.Properties[HttpRequestMessageProperty.Name]; 字符串accept=httpRequest.Headers[HttpRequestHeader.accept]; string operationName=request.Properties[WebHttpDispatchOperationSelector.HttpOperationNamePropertyName]作为字符串; 如果(接受==“文本/html”) { OperationContext.Current.Extensions.Add(新的MyUseHtmlExtension{UseHtmlResponse=true,OperationName=OperationName}); } 返回null; } SendReply之前的公共无效(参考消息回复,对象关联状态) { } } 类MyUseHtmlExtension:IExtension { 公共无效附加(OperationContext所有者){} 公共无效分离(OperationContext所有者){} 公共bool UseHtmlResponse{get;set;} 公共字符串操作名{get;set;} } 公共类MyHtmlLaWareEndpointBehavior:IEndpointBehavior { public void AddBindingParameters(ServiceEndpoint端点、BindingParameterCollection bindingParameters) { } 公共空间