如何从一个Web API方法返回的XML数据？ [英] How to return Xml Data from a Web API Method?

问题描述

我有一个Web API方法应返回的XML数据，但它返回字符串：

 公共类HealthCheckController：ApiController
    {
        [HTTPGET]
        公共字符串指数（）
        {
            VAR healthCheckReport =新HealthCheckReport（）;            返回healthCheckReport.ToXml（）;
        }
    }
 

返回的是：

 ＆LT;字符串的xmlns =htt​​p://schemas.microsoft.com/2003/10/Serialization/＆GT;
＆LT; myroot＆GT;＆LT;＆MYNODE GT;＆LT; / MYNODE＆GT;＆LT; / myroot＆GT;
＆LT; /串＆GT;
 

和我加入这个映射：

  config.Routes.MapHttpRoute（
              名称：健康检查，
              routeTemplate：健康检查，
              默认：新
              {
                  控制器=健康检查，
                  行动=索引
              }）;
 

如何使它只返回XML位：

 ＆LT; myroot＆GT;＆LT;＆MYNODE GT;＆LT; / MYNODE＆GT;＆LT; / myroot＆GT;
 

如果我只用MVC，我就可以用下面的，但网络API不支持内容：

  [HTTPGET]
        公众的ActionResult指数（）
        {
            VAR healthCheckReport =新HealthCheckReport（）;            返回内容（healthCheckReport.ToXml（），文/ XML）;
        }
 

我还增加了以下codeS到WebApiConfig类：

  config.Formatters.Remove（config.Formatters.JsonFormatter）;
 config.Formatters.XmlFormatter.UseXmlSerializer =真;
 

解决方案

最快捷的方式是这样的，

公共类HealthCheckController：ApiController
 {
     [HTTPGET]
     公众的Htt presponseMessage指数（）
     {
         VAR healthCheckReport =新HealthCheckReport（）;         返回新的Htt presponseMessage（）{内容=新的StringContent（healthCheckReport.ToXml（），Encoding.UTF8，应用程序/ XML）};
     }
 }


但它也很容易建立，从HttpContent派生直接支持XmlDocument的或的XDocument一个新XmlContent类。例如

公共类XmlContent：HttpContent
{
    私人只读的MemoryStream _Stream =新的MemoryStream（）;    公共XmlContent（XmlDocument的文件）{
        document.Save（_Stream）;
            _Stream.Position = 0;
        Headers.ContentType =新MediaTypeHeaderValue（应用程序/ XML）;
    }    保护覆盖任务SerializeToStreamAsync（流流，System.Net.TransportContext上下文）{        _Stream.CopyTo（流）;        VAR TCS =新TaskCompletionSource＆LT;对象＆gt;（）;
        tcs.SetResult（NULL）;
        返回tcs.Task;
    }    保护覆盖布尔TryComputeLength（出长长度）{
        长度= _Stream.Length;
        返回true;
    }
}


和您可以使用它，就像你会使用StreamContent或的StringContent，但它接受的XmlDocument，

公共类HealthCheckController：ApiController
{
    [HTTPGET]
    公众的Htt presponseMessage指数（）
    {
       VAR healthCheckReport =新HealthCheckReport（）;       返回新的Htt presponseMessage（）{
           RequestMessage =请求，
           内容=新XmlContent（healthCheckReport.ToXmlDocument（））};
    }
}


I have a Web Api method which should return an xml data but it returns string:

 public class HealthCheckController : ApiController
    {       
        [HttpGet]
        public string Index()
        {
            var healthCheckReport = new HealthCheckReport();

            return healthCheckReport.ToXml();
        }
    }

It returns:

<string xmlns="http://schemas.microsoft.com/2003/10/Serialization/">
<myroot><mynode></mynode></myroot>
</string>

and I have added this mapping:

 config.Routes.MapHttpRoute(
              name: "HealthCheck",
              routeTemplate: "healthcheck",
              defaults: new
              {
                  controller = "HealthCheck",
                  action = "Index"
              });

How to make it return just the xml bits:

<myroot><mynode></mynode></myroot>

If I was using just MVC, I could be using the below but Web API doesn't support "Content":

 [HttpGet]
        public ActionResult Index()
        {
            var healthCheckReport = new HealthCheckReport();

            return Content(healthCheckReport.ToXml(), "text/xml");
        }

I have also added the below codes to the WebApiConfig class:

 config.Formatters.Remove(config.Formatters.JsonFormatter);
 config.Formatters.XmlFormatter.UseXmlSerializer = true;

解决方案

The quickest way is this,

 public class HealthCheckController : ApiController
 {       
     [HttpGet]
     public HttpResponseMessage Index()
     {
         var healthCheckReport = new HealthCheckReport();

         return new HttpResponseMessage() {Content = new StringContent( healthCheckReport.ToXml(), Encoding.UTF8, "application/xml" )};
     }
 }

but it is also very easy to build a new XmlContent class that derives from HttpContent to support XmlDocument or XDocument directly. e.g.

public class XmlContent : HttpContent
{
    private readonly MemoryStream _Stream = new MemoryStream();

    public XmlContent(XmlDocument document) {
        document.Save(_Stream);
            _Stream.Position = 0;
        Headers.ContentType = new MediaTypeHeaderValue("application/xml");
    }

    protected override Task SerializeToStreamAsync(Stream stream, System.Net.TransportContext context) {

        _Stream.CopyTo(stream);

        var tcs = new TaskCompletionSource<object>();
        tcs.SetResult(null);
        return tcs.Task;
    }

    protected override bool TryComputeLength(out long length) {
        length = _Stream.Length;
        return true;
    }
}

and you can use it just like you would use StreamContent or StringContent, except that it accepts a XmlDocument,

public class HealthCheckController : ApiController
{       
    [HttpGet]
    public HttpResponseMessage Index()
    {
       var healthCheckReport = new HealthCheckReport();

       return new HttpResponseMessage() {
           RequestMessage = Request,
           Content = new XmlContent(healthCheckReport.ToXmlDocument()) };
    }
}

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