Re: Using a local DTD

David Bertoni Fri, 01 Jan 2010 13:21:37 -0800

On 1/1/2010 2:53 AM, David Webber wrote:

Hi,


I am new to Xerces but have successfully got a DOMLSParser to work in C++ -
in as far as I can load a document and find its nodes.

However the

parseURI( pszFilename );

takes forever (over a minute) validating according to a DOCTYPE
statement of
the form:

<!DOCTYPE score-partwise PUBLIC "-//Recordare//DTD MusicXML 1.0
Partwise//EN" "http://www.musicxml.org/dtds/partwise.dtd";>

I want to replace the reference to the DTD by a reference to a copy on my
machine when calling parseURI( ).

It looks to me like I need to use the DOMLSResourseResolver and DOMLSInput
classes but the documentation requires a level of knowledge and
understanding which I do not have.

Is there any sample code anywhere showing exactly how to do this?

It's pretty straightforward:

1. Derive your own class from DOMLSResourceResolver and implement theresolveResource() function. The implementation should just compare thepublic ID parameter with the public ID of the DTD you want to load locally:


#include "xercesc/dom/DOMLSResourceResolver.h"
#include "xercesc/util/XMLString.h"
#include "xercesc/framework/Wrapper4InputSource.hpp"
#include "xercesc/framework/LocalFileInputSource.hpp"


class myResolver : public DOMLSResourceResolver {
 public:
  myResolver();
  virtual ~myResolver();

  virtual DOMLSInput* resolveResource(const XMLCh* const    resourceType
                                      , const XMLCh* const  namespaceUri
                                      , const XMLCh* const  publicId
                                      , const XMLCh* const  systemId
                                      , const XMLCh* const  baseURI);
 private:
  const XMLCh* m_publicID;
  const char* m_fileName;
};

myResolver::myResolver()

: m_publicID(XMLString::transcode("-//Recordare//DTD MusicXML 1.0Partwise//EN")),

      m_fileName("/home/dbertoni/dtds/partwise.dtd") {
}

myResolver::~myResolver() {
    XMLString::release(&m_publicID);
}

DOMLSInput* myResolver::resolveResource(const XMLCh* const    resourceType

, const XMLCh* constnamespaceUri

                                        , const XMLCh* const    publicId
                                        , const XMLCh* const    systemId
                                        , const XMLCh* const    baseURI) {

  if (!XMLString::compareString(m_publicId, publicId)) {
    return new Wrapper4InputSource(new LocalFileInputSource(m_fileName));
  } else {
    return 0;
  }
}

2. Install your resolver into the parser:

myResolver resolver;

const XMLCh* parameter = XMLString::transcode("resource-resolver");

parser->getDomConfig()->setParameter(parameter, &resolver);

XMLString::release(&parameter);

Dave

Re: Using a local DTD

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