/*
* Copyright 2006-2008 Sxip Identity Corporation
*/
package org.openid4java.discovery.yadis;
import javax.xml.transform.TransformerException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.html.dom.HTMLDocumentImpl;
import org.openid4java.OpenIDException;
import org.openid4java.util.OpenID4JavaDOMParser;
import org.openid4java.discovery.yadis.YadisException;
import org.openid4java.discovery.yadis.YadisHtmlParser;
import org.openid4java.discovery.yadis.YadisResolver;
import org.w3c.dom.NodeList;
import org.w3c.dom.html.HTMLHeadElement;
import org.w3c.dom.html.HTMLMetaElement;
/**
* A {@link org.openid4java.discovery.yadis.YadisHtmlParser} implementation using the DOMParser of CyberNeko HTML.
*
* @author Sutra Zhou
* @since 0.9.4
* @see org.openid4java.util.OpenID4JavaDOMParser
*/
public class CyberNekoDOMYadisHtmlParser implements YadisHtmlParser
{
private static final Log _log = LogFactory.getLog(CyberNekoDOMYadisHtmlParser.class);
private static final boolean DEBUG = _log.isDebugEnabled();
/*
* (non-Javadoc)
*
* @see org.openid4java.discovery.yadis.YadisParser#getHtmlMeta(java.lang.String)
*/
public String getHtmlMeta(String input) throws YadisException
{
String xrdsLocation = null;
HTMLDocumentImpl doc = this.parseDocument(input);
if (DEBUG)
{
try
{
_log.debug("document:\n" + OpenID4JavaDOMParser.toXmlString(doc));
} catch (TransformerException e)
{
_log.debug("An exception occurs while transforming the document to string in debugging.", e);
}
}
NodeList heads = doc.getElementsByTagName("head");
if (heads.getLength() != 1)
throw new YadisException(
"HTML response must have exactly one HEAD element, "
+ "found " + heads.getLength() + " : "
+ heads.toString(),
OpenIDException.YADIS_HTMLMETA_INVALID_RESPONSE);
HTMLHeadElement head = (HTMLHeadElement) doc.getHead();
NodeList metaElements = head.getElementsByTagName("META");
if (metaElements == null || metaElements.getLength() == 0)
{
if (DEBUG)
_log.debug("No <meta> element found under <html><head>. " +
"See Yadis specification, section 6.2.5/1.");
}
else
{
for (int i = 0, len = metaElements.getLength(); i < len; i++)
{
HTMLMetaElement metaElement = (HTMLMetaElement) metaElements.item(i);
String httpEquiv = metaElement.getHttpEquiv();
if (YadisResolver.YADIS_XRDS_LOCATION.equalsIgnoreCase(httpEquiv))
{
if (xrdsLocation != null)
throw new YadisException(
"More than one "
+ YadisResolver.YADIS_XRDS_LOCATION
+ "META tags found in HEAD: "
+ head.toString(),
OpenIDException.YADIS_HTMLMETA_INVALID_RESPONSE);
xrdsLocation = metaElement.getContent();
if (DEBUG)
_log.debug("Found " + YadisResolver.YADIS_XRDS_LOCATION
+ " META tags.");
}
}
}
return xrdsLocation;
}
private HTMLDocumentImpl parseDocument(String htmlData) throws YadisException
{
OpenID4JavaDOMParser parser = new OpenID4JavaDOMParser();
try
{
parser.parse(OpenID4JavaDOMParser.createInputSource(htmlData));
}
catch (Exception e)
{
throw new YadisException("Error parsing HTML message",
OpenIDException.YADIS_HTMLMETA_INVALID_RESPONSE, e);
}
if (parser.isIgnoredHeadStartElement())
{
throw new YadisException("HTML response must have exactly one HEAD element.",
OpenIDException.YADIS_HTMLMETA_INVALID_RESPONSE);
}
return (HTMLDocumentImpl) parser.getDocument();
}
}