c# - 将通用对象序列化为 SOAP 格式流的扩展方法

Question

我很难找到一种通用的扩展方法，可以将给定的对象序列化为 SOAP 格式。实际的实现看起来有点像这样:

Foobar.cs

[Serializable, XmlRoot("foobar"), DataContract]
public class Foobar
{
    [XmlAttribute("foo"), DataMember]
    public string Foo { get; set; }

    [XmlAttribute("bar"), DataMember]
    public string Bar { get; set; }

    public Foobar() {}
}

Lipsum.cs

[Serializable, XmlRoot("lipsum"), XmlType("lipsum"), DataContract]
public class Lipsum
{
    private List<Foobar> lipsum = new List<Foobar>();

    [XmlElement("foobar"), DataMember]
    public List<Foobar> Lipsum { get { return lipsum; } }
}

Extensions.cs

public static void SerializeToSoap<T>(this Stream target, T source)
{
    XmlTypeMapping xmlTypeMapping = (new SoapReflectionImporter().ImportTypeMapping(typeof(T)));
    XmlSerializer xmlSerializer = new XmlSerializer(xmlTypeMapping);
    xmlSerializer.Serialize(target, source);
}

Program.cs

static void Main()
{
    Lipsum lipsum = new Lipsum();
    lipsum.Lipsum.Add(
        new Foobar()
        {
            Foo = "Lorem",
            Bar = "Ipsum"
        }
    );

    using (MemoryStream persistence = new MemoryStream())
    {
        persistence.SerializeToSoap<Lipsum>(lipsum);
        Console.WriteLine(Encoding.Default.GetString(persistence.ToArray()));
        Console.WriteLine(Environment.NewLine);
    }
}

异常(exception)情况

System.InvalidOperationException: Token StartElement in state Epilog would result in an invalid XML document.
   at System.Xml.XmlTextWriter.AutoComplete(Token token)
   at System.Xml.XmlTextWriter.WriteStartElement(String prefix, String localName, String ns)
   at System.Xml.Serialization.XmlSerializationWriter.WriteStartElement(String name, String ns, Object o, Boolean writePrefixed, XmlSerializerNamespaces xmlns)
   at System.Xml.Serialization.XmlSerializationWriter.WriteArray(String name, String ns, Object o, Type type)
   at System.Xml.Serialization.XmlSerializationWriter.WriteReferencedElement(String name, String ns, Object o, Type ambientType)
   at System.Xml.Serialization.XmlSerializationWriter.WriteReferencedElements()
   at Microsoft.Xml.Serialization.GeneratedAssembly.XmlSerializationWriter1.
   Write4_Lipsum(Object o)

另一方面，XML 和 JSON 序列化(分别使用 XmlSerializer 和 DataContractJsonSerializer)工作正常具有以下预期结果:

<?xml version="1.0"?>
<lipsum xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <foobar foo="Lorem" bar="Ipsum" />
</lipsum>

{"Lipsum":[{"Foo":"Lorem","Bar":"Ipsum"}]}

我们将不胜感激任何建议。非常感谢。

更新

正如其中一位评论者所说，有一个 SoapFormatter 类，但考虑到我知道它不能处理泛型类型，所以没有包含该片段。所以无论如何，这将是该场景的代码:

public static void SerializeToSoap<T>(this Stream target, T source)
{
    SoapFormatter soapFormatter = new SoapFormatter();
    soapFormatter.Serialize(target, source);
}

抛出以下异常:

Exception caught: Soap Serializer does not support serializing Generic Types : System.Collections.Generic.List`1[Foobar].

更新 2

在 Merlyn Morgan-Graham 的指导下，我尝试用非泛型对象为 SoapFormatter 提供数据，因此在对 MemoryStream 进行了一些调整之后，我结果是这样的:

using (MemoryStream xmlStream = new MemoryStream())
{
    XmlSerializer xmlSerializer = new XmlSerializer(typeof(T));
    xmlSerializer.Serialize(xmlStream, lipsum);

    using (MemoryStream soapStream = new MemoryStream()) 
    {
        SoapFormatter soapFormatter = new SoapFormatter();
        soapFormatter.Serialize(soapStream, Encoding.Default.GetString(xmlStream.ToArray()));
        Console.WriteLine(Encoding.Default.GetString(soapStream.ToArray()));
        Console.WriteLine(Environment.NewLine);
    }
}

令人惊讶的是，抛开字符实体，输出了一条不错的 SOAP 消息:

<SOAP-ENV:Envelope
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:xsd="http://www.w3.org/2001/XMLSchema"
    xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/"
    xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"
    xmlns:clr="http://schemas.microsoft.com/soap/encoding/clr/1.0"
    SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
    <SOAP-ENV:Body>
        <SOAP-ENC:string id="ref-1">
            &#60;?xml version=&#34;1.0&#34;?&#62;&#60;lipsum
            xmlns:xsi=&#34;http://www.w3.org/2001/XMLSchema-instance&#34;
            xmlns:xsd=&#34;http://www.w3.org/2001/XMLSchema&#34;&#62;&#60;
            foobar foo=&#34;Lorem&#34; bar=&#34;Ipsum&#34;/&#62;&#60;/lipsum&#62;
        </SOAP-ENC:string>
    </SOAP-ENV:Body>
</SOAP-ENV:Envelope>

Answer 1

我(一半)通过用另一个元素包装序列化解决了这个问题，就像这个论坛帖子:http://forums.asp.net/p/1510998/3607468.aspx ，以及这篇博文:http://sandblogaspnet.blogspot.com/2009/07/serialization-in-net-3.html

public static void SerializeToSoap<T>(this Stream target, T source)
{
    XmlTypeMapping xmlTypeMapping = (new SoapReflectionImporter().ImportTypeMapping(typeof(T)));
    XmlSerializer xmlSerializer = new XmlSerializer(xmlTypeMapping);
    using (var xmlWriter = new XmlTextWriter(target, Encoding.UTF8))
    {
        xmlWriter.WriteStartDocument();
        xmlWriter.WriteStartElement("root");
        xmlSerializer.Serialize(xmlWriter, source);
        xmlWriter.WriteFullEndElement();
    }
}

不过，该文档看起来很奇怪，并且不包含 SOAP 信封。诚然，我对 SOAP 知之甚少，所以也许您知道如何解决这些问题:)

编辑:

查看 System.Web.Services.Protocols.SoapHttpClientProtocol 中的反射源，看起来使用了 SoapReflectionImporter 和 XmlSerializer，但是SOAP 信封和正文直接在序列化代码中生成。没有特殊的助手暴露给用户。因此，您可能必须使用自定义代码包装消息的这一部分。

从好的方面来说，代码看起来相当简单 - 只需使用正确的命名空间/属性编写正确的元素。