Set the User-Agent HTTP header so we can download XML files from www.w3.org

https://sourceforge.net/p/xml-copy-editor/discussion/475215/thread/223a81b85b/

Xerces-C has to be patched https://github.com/apache/xerces-c/pull/1

src/wrapxerces.cpp

@@ -20,6 +20,7 @@
 
 #include "wrapxerces.h"
 #include "pathresolver.h"
+#include "xercesnetaccessor.h"
 
 #include <xercesc/parsers/XercesDOMParser.hpp>
 #include <xercesc/sax2/XMLReaderFactory.hpp>
@@ -46,10 +47,16 @@ void WrapXerces::Init ( bool enableNetAccess ) throw()
 		Initializer ()
 		{
 			XMLPlatformUtils::Initialize();
+
 			mOriginalNetAccessor = XMLPlatformUtils::fgNetAccessor;
+			if ( mOriginalNetAccessor != NULL )
+			{
+				mOriginalNetAccessor = new XercesNetAccessor ( mOriginalNetAccessor );
+			}
 		}
 		~Initializer()
 		{
+			delete mOriginalNetAccessor;
 			XMLPlatformUtils::Terminate();
 		}
 	} dummy;

src/xercesnetaccessor.cpp

@@ -0,0 +1,62 @@
+/*
+ * Copyright 2018 Zane U. Ji.
+ *
+ * This file is part of Xml Copy Editor.
+ *
+ * Xml Copy Editor is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * Xml Copy Editor is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Xml Copy Editor; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include "xercesnetaccessor.h"
+#include "xmlcopyeditorcopy.h"
+
+#include <wx/string.h>
+#include <string.h>
+#include <string>
+
+const static char USER_AGENT[] = "User-Agent:";
+
+XercesNetAccessor::XercesNetAccessor ( XMLNetAccessor *netAccessor )
+	: mNetAccessor ( netAccessor )
+{
+}
+
+const XMLCh *XercesNetAccessor::getId() const
+{
+	return mNetAccessor->getId();
+}
+
+BinInputStream *XercesNetAccessor::makeNew (
+	const XMLURL &urlSrc,
+	const XMLNetHTTPInfo *httpInfo /* = 0 */
+) {
+
+	XMLNetHTTPInfo info;
+	if ( httpInfo != NULL )
+	{
+		info = *httpInfo;
+	}
+	std::string headers ( info.fHeaders, info.fHeadersLen );
+	if ( headers.find ( USER_AGENT ) == std::string::npos )
+	{
+		headers.append ( USER_AGENT );
+		headers.append ( " xmlcopyeditor/" );
+		headers.append ( wxString ( ABOUT_VERSION ).utf8_str() );
+		headers.append ( "\r\n" );
+		info.fHeaders = headers.c_str();
+		info.fHeadersLen = headers.length();
+	}
+
+	return mNetAccessor->makeNew ( urlSrc, &info );
+}

src/xercesnetaccessor.h

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2018 Zane U. Ji.
+ *
+ * This file is part of Xml Copy Editor.
+ *
+ * Xml Copy Editor is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * Xml Copy Editor is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Xml Copy Editor; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#ifndef XERCESNETACCESSOR_H_
+#define XERCESNETACCESSOR_H_
+
+#include <xercesc/util/XMLNetAccessor.hpp>
+
+using namespace xercesc;
+
+class XercesNetAccessor : public XMLNetAccessor
+{
+public:
+	XercesNetAccessor ( XMLNetAccessor *netAccesor );
+
+	virtual const XMLCh *getId() const;
+
+	virtual BinInputStream *makeNew ( const XMLURL &urlSrc,
+		const XMLNetHTTPInfo *httpInfo = 0);
+
+protected:
+	XMLNetAccessor *mNetAccessor;
+};
+
+#endif /* XERCESNETACCESSOR_H_ */