我们的 WCF Web 服务的一些消费者在尝试解析我们的响应时遇到异常:

System.InvalidOperationException: There is an error in XML document (5, -349).
   at System.Xml.Serialization.XmlSerializer.Deserialize(XmlReader xmlReader, String encodingStyle, XmlDeserializationEvents events)
   at System.Xml.Serialization.XmlSerializer.Deserialize(XmlReader xmlReader, String encodingStyle)
   at System.Web.Services.Protocols.SoapHttpClientProtocol.ReadResponse(SoapClientMessage message, WebResponse response, Stream responseStream, Boolean asyncCall)
   at System.Web.Services.Protocols.SoapHttpClientProtocol.Invoke(String methodName, Object[] parameters)
   at [Consumer's Code]

内部异常看起来像这样:

'', hexadecimal value 0x0B, is an invalid character. Line 5, position -349.

   at System.Xml.XmlTextReaderImpl.Throw(Exception e)
   at System.Xml.XmlTextReaderImpl.Throw(String res, String[] args)
   at System.Xml.XmlTextReaderImpl.ThrowInvalidChar(Int32 pos, Char invChar)
   at System.Xml.XmlTextReaderImpl.ParseNumericCharRefInline(Int32 startPos, Boolean expand, BufferBuilder internalSubsetBuilder, Int32& charCount, EntityType& entityType)
   at System.Xml.XmlTextReaderImpl.ParseCharRefInline(Int32 startPos, Int32& charCount, EntityType& entityType)
   at System.Xml.XmlTextReaderImpl.ParseText(Int32& startPos, Int32& endPos, Int32& outOrChars)
   at System.Xml.XmlTextReaderImpl.ParseText()
   at System.Xml.XmlTextReaderImpl.ParseElementContent()
   at System.Xml.XmlTextReaderImpl.Read()
   at System.Xml.XmlTextReader.Read()
   at System.Xml.XmlReader.ReadElementString()
   at Microsoft.Xml.Serialization.GeneratedAssembly.XmlSerializationReader1.Read43_TextWidgetConfig(Boolean isNullable, Boolean checkType)
   at Microsoft.Xml.Serialization.GeneratedAssembly.XmlSerializationReader1.Read45_TextWidgetInfo(Boolean isNullable, Boolean checkType)
   at Microsoft.Xml.Serialization.GeneratedAssembly.XmlSerializationReader1.Read49_WidgetInfo(Boolean isNullable, Boolean checkType)
   at Microsoft.Xml.Serialization.GeneratedAssembly.XmlSerializationReader1.Read50_InstantPageData(Boolean isNullable, Boolean checkType)
   at Microsoft.Xml.Serialization.GeneratedAssembly.XmlSerializationReader1.Read128_GetInstantPageDataResponse()
   at Microsoft.Xml.Serialization.GeneratedAssembly.ArrayOfObjectSerializer141.Deserialize(XmlSerializationReader reader)
   at System.Xml.Serialization.XmlSerializer.Deserialize(XmlReader xmlReader, String encodingStyle, XmlDeserializationEvents events)

不知何故返回的客户数据中有垂直制表符。查看我们的 XML，我们可以看到这些字符被正确呈现为  实体。通过快速 Google 搜索，我们发现 XmlSerializer 存在一个错误，它无法处理某些实体，必须通过更改自动生成的代理的 XML 阅读器中的选项来修复该错误.

消费者承认他们需要修复客户端代码，但他们无法通过补丁快速响应此问题。他们希望我们在自己的代码中应用补丁来过滤掉这些禁用字符。

1. 是否在任何地方记录了 XmlSerializer 的问题字符列表？
2. 是否有一种干净的方法来更改我们的 WCF 服务，以便我们可以自动删除字符，而无需在我们所有的网络方法中进行字符串替换？

更新:

我找到了#1 的答案。根据the XML spec , 只允许某些字符代码:

Char ::= #x9 | #xA | #xD | [#x20-#xD7FF] | [#xE000-#xFFFD] | [#x10000-#x10FFFF]

所以我们服务器上的 DataContractSerializer 似乎是这里的错误所在。我现在正在研究如何自定义该序列化程序。

更新 2:

看起来 DataContractSerializer 问题是已知的并且 logged in Microsoft Connect .

最佳答案

这是我的解决方法代码。我对此不是很高兴；它并没有涵盖所有情况(尽管它满足了我的需求)，而且感觉应该有一个更简单的解决方案。我会把它贴在这里，希望其他人可以做得更好，或者有人有更简单的答案。

为了解决这个问题，我创建了一个新的操作行为属性来将序列化程序更改为自定义序列化程序，该序列化程序会去除将呈现为无效 XML 实体的字符:

public class StripInvalidXmlCharactersBehaviorAttribute 
    : Attribute, IOperationBehavior
{
    public void AddBindingParameters(
        OperationDescription operationDescription, 
        BindingParameterCollection bindingParameters)
    {
    }

    public void ApplyClientBehavior(
        OperationDescription operationDescription, 
        ClientOperation clientOperation)
    {
        IOperationBehavior behavior =
            new StripInvalidXmlCharactersBehavior(operationDescription);
        behavior.ApplyClientBehavior(operationDescription, clientOperation);
    }

    public void ApplyDispatchBehavior(
        OperationDescription operationDescription, 
        DispatchOperation dispatchOperation)
    {
        IOperationBehavior behavior =
            new StripInvalidXmlCharactersBehavior(operationDescription);
        behavior.ApplyDispatchBehavior(
            operationDescription, dispatchOperation);
    }

    public void Validate(OperationDescription operationDescription)
    {
    }
}

行为本身看起来像这样:

internal class StripInvalidXmlCharactersBehavior 
    : DataContractSerializerOperationBehavior
{
    public StripInvalidXmlCharactersBehavior(OperationDescription opDesc)
        : base(opDesc)
    {
    }

    public override XmlObjectSerializer CreateSerializer(
        Type type, string name, string ns, IList<Type> knownTypes)
    {
        return new InvalidXmlStrippingSerializer(type, name, ns, knownTypes);
    }

    public override XmlObjectSerializer CreateSerializer(
        Type type, XmlDictionaryString name, XmlDictionaryString ns, 
        IList<Type> knownTypes)
    {
        return new InvalidXmlStrippingSerializer(type, name, ns, knownTypes);
    }
}

这是序列化器:

internal class InvalidXmlStrippingSerializer : XmlObjectSerializer
{
    private DataContractSerializer _innerSerializer;

    public InvalidXmlStrippingSerializer(
        Type type, string name, string ns, IList<Type> knownTypes)
    {
        _innerSerializer = 
            new DataContractSerializer(type, name, ns, knownTypes);
    }

    public InvalidXmlStrippingSerializer(
        Type type, XmlDictionaryString name, XmlDictionaryString ns, 
        IList<Type> knownTypes)
    {
        _innerSerializer =
            new DataContractSerializer(type, name, ns, knownTypes);
    }

    public override bool IsStartObject(XmlDictionaryReader reader)
    {
        return _innerSerializer.IsStartObject(reader);
    }

    public override object ReadObject(
        XmlDictionaryReader reader, bool verifyObjectName)
    {
        return _innerSerializer.ReadObject(reader, verifyObjectName);
    }

    public override void WriteEndObject(XmlDictionaryWriter writer)
    {
        _innerSerializer.WriteEndObject(writer);
    }

    public override void WriteObjectContent(
        XmlDictionaryWriter writer, object graph)
    {
        graph = fixBadStringsRecursive(graph);
        _innerSerializer.WriteObjectContent(writer, graph);
    }

    private object fixBadStringsRecursive(object graph)
    {
        var objType = graph.GetType();
        if (objType == typeof(string))
        {
            graph = removeInvalidCharacters(graph as string);
        }
        else if (graph is IEnumerable)
        {
            foreach (var item in graph as IEnumerable)
            {
                fixBadStringsRecursive(item);
            }
        }
        else if (objType.IsClass)
        {
            // Look through the properties of the object 
            foreach (var prop in graph.GetType().GetProperties())
            {
                var propParams = prop.GetIndexParameters();
                if ((propParams == null || propParams.Length == 0)
                    && prop.GetGetMethod() != null)
                {
                    var propVal = prop.GetValue(graph, null);
                    if (propVal != null)
                    {
                        propVal = fixBadStringsRecursive(propVal);
                        if (prop.GetSetMethod() != null)
                        {
                            prop.SetValue(graph, propVal, null);
                        }
                    }
                }
            }
        }
        return graph;
    }

    private static string removeInvalidCharacters(string source)
    {
        // This is per the W3C XML spec:
        // http://www.w3.org/TR/xml/#NT-Char
        return new string(
            (
                from ch in source
                where
                    ch == '\u0009' || ch == '\u000a' || ch == '\u000d'
                    || (ch >= '\u0020' && ch <= '\ud7ff')
                    || (ch >= '\ue000' && ch <= '\ufffd')
                select ch
            ).ToArray()
        );
    }

    public override void WriteStartObject(
        XmlDictionaryWriter writer, object graph)
    {
        _innerSerializer.WriteStartObject(writer, graph);
    }
}

要将行为应用于我的操作，我现在只需添加我创建的属性即可。

关于.net - SOAP 客户端未正确处理 XML 实体；遇到 "There is an error in XML document"，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/5021083/