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copied!<p>When your <code>ResolveUri</code> method gets a request for a "public" form of the URI like <code>-//W3C//ELEMENTS XHTML Images 1.0//EN</code> then does your method throw and wait for the subsequent web-like URI which begins with <code>http://</code>?</p> <p>Instead of throwing, I resolve the public URI to the corresponding <code>http://</code> URI (and then in my <code>GetEntity</code> method I intercept requests to the <code>http://</code> URIs).</p> <p>I therefore never have to throw, which I think is the right solution.</p> <hr> <blockquote> <p>That's a smart way to do it. How big is your dictionary? The library I pointed you to handles only XHTML 1.0, and there is just one public URI base that would need to be mapped.</p> </blockquote> <p>I'm using XHTML 1.1 which is 'modular' so I have to map about 40 files.</p> <p>Beware that the Framework's behaviour may have changed! I have a library (including my XhtmlUrlResolver class) which is built with the .NET Framework 2, but it's invoked differently depending on whether the application (which uses the library) is build for .NET 2 or .NET 4.</p> <p>With .NET 2, when my ResolveUri method always only delegated transparently to a XmlUrlResolver, then it would:</p> <ol> <li>Ask to ResolveUri the public of the DTD.</li> <li>Try to GetEntity the DTD from disk (throws one DirectoryNotFoundException)</li> <li>Try to GetEntity the DTD from http (which I'd serve from local resources)</li> <li>Try to GetEntity every other file from http (which I'd serve from local resources)</li> </ol> <p>With .NET 4 there was an extra call for every resource:</p> <ul> <li>Ask to ResolveUri the public of the sub-resource (e.g. the <code>*.mod</code> file), which my implementation just delegated to XmlUrlResolver</li> <li>Ask to GetEntity the 'resolved' public of the sub-resource, which wasn't really resolved at all, it just had an http-like prefix added (throws WebException)</li> </ul> <p>Throwing all those WebExceptions slowed down processing a lot, which is why I revisited this to look for a fix.</p> <p>Your suggestion, that I throw from ResolveUri, solved that problem, for which I thank you; but instead of throwing, returning something from ResolveUri is more elegant (and a bit faster: 40 fewer exceptions).</p> <p>Here's my current source code.</p> <pre><code>using System; using System.Collections.Generic; using System.Text; using System.Reflection; using System.IO; using System.Xml; //don't obfuscate the file names of the embedded resources, //which are contained in a "Files" subfolder of the project [assembly: Obfuscation(Feature = "Apply to ModelText.ModelXml.Files.*: all", Exclude = true, ApplyToMembers = true)] namespace ModelText.ModelXml { /// <summary> /// This class provides local (i.e. faster) access to the XHTML DTD. /// </summary> /// <remarks> /// Another way to implement this class is described in MSDN "Customizing the XmlUrlResolver Class" /// which shows as an example a "class XmlCachingResolver" /// and which is implemented using WebRequest and HttpRequestCachePolicy /// </remarks> [System.Reflection.ObfuscationAttribute(Feature = "renaming", ApplyToMembers = true)] public class XhtmlUrlResolver : XmlResolver { XmlUrlResolver m_xmlUrlResolver = new XmlUrlResolver(); Assembly m_assembly = Assembly.GetExecutingAssembly(); public override object GetEntity(Uri absoluteUri, string role, Type ofObjectToReturn) { string uriString = absoluteUri.ToString(); if (s_resources.uriExists(uriString)) { //Console.WriteLine("XhtmlUrlResolver Found {0} -- {1}", uriString, DateTime.Now); //to get the filename of the embedded resource, remove the http: directory //this is OK because the filenames are unique and map 1-to-1 with resource names string filename = uriString.Substring(uriString.LastIndexOf('/') + 1); Stream stream = m_assembly.GetManifestResourceStream(typeof(XhtmlUrlResolver), "Files." + filename); return stream; } //Console.WriteLine("XhtmlUrlResolver Throwing {0} -- {1}", uriString, DateTime.Now); throw new ArgumentException(); //Console.WriteLine("XhtmlUrlResolver Getting {0} -- {1}", uriString, DateTime.Now); //object o = m_xmlUrlResolver.GetEntity(absoluteUri, role, ofObjectToReturn); //Console.WriteLine("XhtmlUrlResolver Got {0} -- {1}", uriString, DateTime.Now); //return o; } public override Uri ResolveUri(Uri baseUri, string relativeUri) { string resolved = s_resources.resolve(relativeUri); if (resolved != null) { //Console.WriteLine("ResolveUri resolving {0}, {1} -- {2}", baseUri, relativeUri, DateTime.Now); return new Uri(resolved); } //Console.WriteLine("ResolveUri passing {0}, {1} -- {2}", baseUri, relativeUri, DateTime.Now); return m_xmlUrlResolver.ResolveUri(baseUri, relativeUri); } public override System.Net.ICredentials Credentials { set { m_xmlUrlResolver.Credentials = value; } } static Resources s_resources = new Resources(); class Resources { Dictionary<string, string> m_publicToUri = new Dictionary<string, string>(); internal Resources() { for (int i = 0, n = array.GetLength(0); i < n; ++i) { m_publicToUri.Add(array[i, 1], array[i, 0]); } } internal bool uriExists(string absoluteUri) { return m_publicToUri.ContainsValue(absoluteUri); } internal string resolve(string relativeUri) { string resolved; if (m_publicToUri.TryGetValue(relativeUri, out resolved)) { return resolved; } return null; } static string[,] array = { { "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd", "-//W3C//DTD XHTML 1.1//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml11-model-1.mod", "-//W3C//ENTITIES XHTML 1.1 Document Model 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-attribs-1.mod", "-//W3C//ENTITIES XHTML Common Attributes 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-base-1.mod", "-//W3C//ELEMENTS XHTML Base Element 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-bdo-1.mod", "-//W3C//ELEMENTS XHTML BIDI Override Element 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-blkphras-1.mod", "-//W3C//ELEMENTS XHTML Block Phrasal 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-blkpres-1.mod", "-//W3C//ELEMENTS XHTML Block Presentation 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-blkstruct-1.mod", "-//W3C//ELEMENTS XHTML Block Structural 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-charent-1.mod", "-//W3C//ENTITIES XHTML Character Entities 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-csismap-1.mod", "-//W3C//ELEMENTS XHTML Client-side Image Maps 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-datatypes-1.mod", "-//W3C//ENTITIES XHTML Datatypes 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-edit-1.mod", "-//W3C//ELEMENTS XHTML Editing Elements 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-events-1.mod", "-//W3C//ENTITIES XHTML Intrinsic Events 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-form-1.mod", "-//W3C//ELEMENTS XHTML Forms 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-framework-1.mod", "-//W3C//ENTITIES XHTML Modular Framework 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-hypertext-1.mod", "-//W3C//ELEMENTS XHTML Hypertext 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-image-1.mod", "-//W3C//ELEMENTS XHTML Images 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-inlphras-1.mod", "-//W3C//ELEMENTS XHTML Inline Phrasal 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-inlpres-1.mod", "-//W3C//ELEMENTS XHTML Inline Presentation 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-inlstruct-1.mod", "-//W3C//ELEMENTS XHTML Inline Structural 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-inlstyle-1.mod", "-//W3C//ELEMENTS XHTML Inline Style 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-lat1.ent", "-//W3C//ENTITIES Latin 1 for XHTML//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-link-1.mod", "-//W3C//ELEMENTS XHTML Link Element 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-list-1.mod", "-//W3C//ELEMENTS XHTML Lists 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-meta-1.mod", "-//W3C//ELEMENTS XHTML Metainformation 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-object-1.mod", "-//W3C//ELEMENTS XHTML Embedded Object 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-param-1.mod", "-//W3C//ELEMENTS XHTML Param Element 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-pres-1.mod", "-//W3C//ELEMENTS XHTML Presentation 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-qname-1.mod", "-//W3C//ENTITIES XHTML Qualified Names 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-script-1.mod", "-//W3C//ELEMENTS XHTML Scripting 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-special.ent", "-//W3C//ENTITIES Special for XHTML//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-ssismap-1.mod", "-//W3C//ELEMENTS XHTML Server-side Image Maps 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-struct-1.mod", "-//W3C//ELEMENTS XHTML Document Structure 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-style-1.mod", "-//W3C//ELEMENTS XHTML Style Sheets 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-symbol.ent", "-//W3C//ENTITIES Symbols for XHTML//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-table-1.mod", "-//W3C//ELEMENTS XHTML Tables 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-target-1.mod", "-//W3C//ELEMENTS XHTML Target 1.0//EN" }, { "http://www.w3.org/MarkUp/DTD/xhtml-text-1.mod", "-//W3C//ELEMENTS XHTML Text 1.0//EN" }, { "http://www.w3.org/TR/ruby/xhtml-ruby-1.mod", "-//W3C//ELEMENTS XHTML Ruby 1.0//EN" } }; } } } </code></pre>

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