.NET自动生成的Web服务客户端：如何避免从w3.org请求架构？

Question

我有一个.NET Web服务客户端，它是使用wsdl.exe工具从wsdl文件自动生成的。

当我第一次实例化生成的类时，它开始从w3.org和其他人那里请求一堆文档。第一个是 http://www.w3.org/2001/XMLSchema.dtd

除了不想给w3.org带来不必要的流量外，我还需要能够在没有连接到互联网的情况下运行应用程序（网络服务是“内部网络服务”）。

任何人都知道解决方案吗？

如果有帮助，这是我没有互联网时的堆栈跟踪：

"An error has occurred while opening external DTD 'http://www.w3.org/2001/XMLSchema.dtd': The remote name could not be resolved: 'www.w3.org'"

   at System.Net.HttpWebRequest.GetResponse()
   at System.Xml.XmlDownloadManager.GetNonFileStream(Uri uri, ICredentials credentials)
   at System.Xml.XmlDownloadManager.GetStream(Uri uri, ICredentials credentials)
   at System.Xml.XmlUrlResolver.GetEntity(Uri absoluteUri, String role, Type ofObjectToReturn)
   at System.Xml.XmlTextReaderImpl.OpenStream(Uri uri)
   at System.Xml.XmlTextReaderImpl.DtdParserProxy_PushExternalSubset(String systemId, String publicId)

   at System.Xml.XmlTextReaderImpl.Throw(Exception e)
   at System.Xml.XmlTextReaderImpl.DtdParserProxy_PushExternalSubset(String systemId, String publicId)
   at System.Xml.XmlTextReaderImpl.DtdParserProxy.System.Xml.IDtdParserAdapter.PushExternalSubset(String systemId, String publicId)
   at System.Xml.DtdParser.ParseExternalSubset()
   at System.Xml.DtdParser.ParseInDocumentDtd(Boolean saveInternalSubset)
   at System.Xml.DtdParser.Parse(Boolean saveInternalSubset)
   at System.Xml.XmlTextReaderImpl.DtdParserProxy.Parse(Boolean saveInternalSubset)
   at System.Xml.XmlTextReaderImpl.ParseDoctypeDecl()
   at System.Xml.XmlTextReaderImpl.ParseDocumentContent()
   at System.Xml.XmlTextReaderImpl.Read()
   at System.Xml.Schema.Parser.StartParsing(XmlReader reader, String targetNamespace)
   at System.Xml.Schema.Parser.Parse(XmlReader reader, String targetNamespace)
   at System.Xml.Schema.XmlSchemaSet.ParseSchema(String targetNamespace, XmlReader reader)
   at System.Xml.Schema.XmlSchemaSet.Add(String targetNamespace, XmlReader schemaDocument)
   at [...]WebServiceClientType..cctor() in [...]

Answer 1

我需要XmlResolver，所以 tamberg的解决方案没有奏效。我通过实现自己的XmlResolver来解决它，它从嵌入式资源中读取必要的模式而不是下载它们。

顺便说一下，这个问题与自动生成的代码没有任何关系。

web-service-client有另一个实现文件包含这样的内容：

public partial class [...]WebServiceClientType
  {
    private static readonly XmlSchemaSet _schema;

    static KeyImportFileType()
    {
      _schema = new XmlSchemaSet();
      _schema.Add(null, XmlResourceResolver.GetXmlReader("http://www.w3.org/TR/2002/REC-xmldsig-core-20020212/xmldsig-core-schema.xsd"));
      _schema.Add(null, XmlResourceResolver.GetXmlReader("http://www.w3.org/TR/2002/REC-xmlenc-core-20021210/xenc-schema.xsd"));
      _schema.Compile();
    }

这个类构造函数失败了。

Answer 2

如果您有权访问XmlReader（或XmlTextReader），则可以执行以下操作：

XmlReader r = ...
r.XmlResolver = null; // prevent xsd or dtd parsing

此致 tamberg

Answer 3

这是我的解决方案。我希望它可以节省一些人不必通过.NET框架进行调试，就像我必须解决XmlUrlResolver的基础一样。它将从本地资源（resx文本文件）加载，缓存或使用XmlUrlResolver默认行为：

using System;
using System.Text;
using System.Text.RegularExpressions;
using System.Xml;
using System.Net;
using System.Net.Cache;
using System.IO;
using System.Resources;

namespace AxureExport {

    //
    // redirect URL resolution to local resource (or cache)
    public class XmlCustomResolver : XmlUrlResolver {

        ICredentials _credentials;
        ResourceManager _resourceManager;

        public enum ResolverType { useDefault, useCache, useResource };
        ResolverType _resolverType;

        public XmlCustomResolver(ResolverType rt, ResourceManager rm = null) {
            _resourceManager = rm != null ? rm : AxureExport.Properties.Resources.ResourceManager;
            _resolverType = rt;
        }

        public override ICredentials Credentials {
            set {
                _credentials = value;
                base.Credentials = value;
            }
        }

        public override object GetEntity(Uri absoluteUri, string role, Type ofObjectToReturn) {
            object response = null;

            if (absoluteUri == null)
                throw new ArgumentNullException(@"absoluteUri");

            switch (_resolverType) {
                default:
                case ResolverType.useDefault:                   // use the default behavior of the XmlUrlResolver
                    response = defaultResponse(absoluteUri, role, ofObjectToReturn);
                    break;

                case ResolverType.useCache:                     // resolve resources thru cache
                    if (!isExternalRequest(absoluteUri, ofObjectToReturn)) {
                        response = defaultResponse(absoluteUri, role, ofObjectToReturn);
                        break;
                    }

                    WebRequest webReq = WebRequest.Create(absoluteUri);
                    webReq.CachePolicy = new HttpRequestCachePolicy(HttpRequestCacheLevel.Default);
                    if (_credentials != null)
                        webReq.Credentials = _credentials;

                    WebResponse wr = webReq.GetResponse();
                    response = wr.GetResponseStream();
                    break;

                case ResolverType.useResource:                  // get resource from internal resource
                    if (!isExternalRequest(absoluteUri, ofObjectToReturn)) {
                        response = defaultResponse(absoluteUri, role, ofObjectToReturn);    // not an external request
                        break;
                    }

                    string resourceName = uriToResourceKey(absoluteUri);
                    object resource = _resourceManager.GetObject(resourceName);
                    if (resource == null)
                        throw new ArgumentException(@"Resource not found.  Uri=" + absoluteUri + @" Local resourceName=" + resourceName);

                    if (resource.GetType() != typeof(System.String))
                        throw new ArgumentException(resourceName + @" is an unexpected resource type.  (Are you setting resource FileType=Text?)");

                    response = ObjectToUTF8Stream(resource);
                    break;
            }

            return response;
        }

        //
        // convert object to stream
        private static object ObjectToUTF8Stream(object o) {
            MemoryStream stream = new MemoryStream();

            StreamWriter writer = new StreamWriter(stream, Encoding.UTF8);
            writer.Write(o);
            writer.Flush();
            stream.Position = 0;

            return stream;
        }

        //
        // default response is to call tbe base resolver
        private object defaultResponse(Uri absoluteUri, string role, Type ofObjectToReturn) {
            return base.GetEntity(absoluteUri, role, ofObjectToReturn);
        }

        //
        // determine whether this is an external request
        private static bool isExternalRequest(Uri absoluteUri, Type ofObjectToReturn) {
            return absoluteUri.Scheme == @"http" && (ofObjectToReturn == null || ofObjectToReturn == typeof(Stream));
        }

        //
        // translate uri to format compatible with reource manager key naming rules
        // see: System.Resources.Tools.StronglyTypedResourceBuilder.VerifyResourceName Method
        //   from http://msdn.microsoft.com/en-us/library/ms145952.aspx:
        private static string uriToResourceKey(Uri absoluteUri) {
            const string repl = @"[ \xA0\.\,\;\|\~\@\#\%\^\&\*\+\-\/\\\<\>\?\[\]\(\)\{\}\" + "\"" + @"\'\:\!]+";
            return Regex.Replace(Path.GetFileNameWithoutExtension(absoluteUri.LocalPath), repl, @"_");
        }
    }
}

Answer 4

感谢Tamberg，你用简洁而正确的答案为我节省了大量时间。我没有意识到默认的解析器会进入网络。检查MSDN是状态 -

  

XmlResolver是System.Xml命名空间中所有类的默认解析程序。您也可以创建自己的解析器......

我已经实现了你的答案，将解析器设置为NULL可以解决问题并减少网络开销。

XmlReader r = ...r.XmlResolver = null; // prevent xsd or dtd parsing

再次感谢， 安迪