/*
* Copyright 2005 Joe Walker
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.directwebremoting.impl;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.StringTokenizer;
import javax.servlet.ServletContext;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.apache.commons.logging.LogFactory;
import org.apache.commons.logging.Log;
import org.directwebremoting.WebContext;
import org.directwebremoting.WebContextFactory;
import org.directwebremoting.extend.PageNormalizer;
import org.directwebremoting.servlet.PathConstants;
import org.directwebremoting.util.DomUtil;
import org.directwebremoting.util.EmptyEntityResolver;
import org.directwebremoting.util.LogErrorHandler;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;
/**
* The default implementation of PageNormalizer attempts to read from
* <code>WEB-INF/web.xml</code> to find a <code>welcome-files</code> element,
* and uses a default of removing "<code>index.html</code>" and
* "<code>index.jsp</code>" if this procedure fails.
* @author Joe Walker [joe at getahead dot ltd dot uk]
*/
public class DefaultPageNormalizer implements PageNormalizer
{
/* (non-Javadoc)
* @see org.directwebremoting.extend.PageNormalizer#normalizePage(java.lang.String)
*/
public String normalizePage(String unnormalized)
{
synchronized (initLock)
{
if (welcomeFiles == null)
{
if (servletContext != null)
{
welcomeFiles = getWebXmlWelcomeFileList(servletContext);
}
else
{
WebContext webContext = WebContextFactory.get();
if (webContext == null)
{
log.warn("Can't find ServletContext to check for <welcome-file-list> in web.xml. Assuming defaults.");
log.warn(" - To prevent this message from happening, either call the PageNormalizer from a DWR thread");
log.warn(" - Or seed the PageNormalizer with a ServletContext before access from outside a DWR thread");
}
else
{
ServletContext threadServletContext = webContext.getServletContext();
welcomeFiles = getWebXmlWelcomeFileList(threadServletContext);
}
}
}
if (welcomeFiles == null)
{
log.debug("Using default welcome file list (index.[jsp|htm[l]])");
welcomeFiles = getDefaultWelcomeFileList();
}
}
if (unnormalized == null)
{
return null;
}
String normalized = unnormalized;
if (!normalizeIncludesQueryString)
{
int queryPos = normalized.indexOf('?');
if (queryPos != -1)
{
normalized = normalized.substring(0, queryPos);
}
}
for (String welcomeFile : welcomeFiles)
{
if (normalized.endsWith(welcomeFile))
{
normalized = normalized.substring(0, normalized.length() - welcomeFile.length());
break;
}
}
return normalized;
}
/**
* Accessor for the list of components to strip to normalize a filename
* @param context Our route to reading web.xml
* @return A list of the welcome files from web.xml or null if none are found there
*/
protected static List<String> getWebXmlWelcomeFileList(ServletContext context)
{
try
{
InputStream in = context.getResourceAsStream(PathConstants.RESOURCE_WEB_XML);
if (in == null)
{
log.warn("Missing " + PathConstants.RESOURCE_WEB_XML);
return null;
}
synchronized (DefaultPageNormalizer.class)
{
if (buildFactory == null)
{
buildFactory = DocumentBuilderFactory.newInstance();
buildFactory.setValidating(false);
}
}
DocumentBuilder builder = buildFactory.newDocumentBuilder();
builder.setEntityResolver(new EmptyEntityResolver());
builder.setErrorHandler(new LogErrorHandler());
InputSource is = new InputSource(in);
Document doc = builder.parse(is);
Element webapp = doc.getDocumentElement();
NodeList welcomeFileListNodes = webapp.getElementsByTagName("welcome-file-list");
if (welcomeFileListNodes.getLength() == 0)
{
log.debug("web.xml contains no <welcome-file-list> element");
return null;
}
List<String> reply = new ArrayList<String>();
for (int i = 0; i < welcomeFileListNodes.getLength(); i++)
{
Element welcomeFileListNode = (Element) welcomeFileListNodes.item(i);
NodeList welcomeFileNodes = welcomeFileListNode.getElementsByTagName("welcome-file");
for (int j = 0; j < welcomeFileNodes.getLength(); j++)
{
Element welcomeFileNode = (Element) welcomeFileNodes.item(j);
String welcomeFile = DomUtil.getText(welcomeFileNode);
reply.add(welcomeFile);
log.debug("Adding welcome-file: " + welcomeFile);
}
}
return reply;
}
catch (Exception ex)
{
log.warn("Failed to calculate welcome files from web.xml.", ex);
return null;
}
}
/**
* Use the default list of components to strip to normalize a filename
* @return A list of the default welcome files
*/
protected static List<String> getDefaultWelcomeFileList()
{
List<String> reply = new ArrayList<String>();
reply.add("index.html");
reply.add("index.htm");
reply.add("index.jsp");
return reply;
}
/**
* Accessor for the list of components to strip to normalize a filename
* @param welcomeFiles the welcomeFiles to set
*/
public void setWelcomeFileList(List<String> welcomeFiles)
{
this.welcomeFiles = welcomeFiles;
}
/**
* Accessor for the list of components to strip to normalize a filename
* @param welcomeFileNames the welcomeFiles to set as a comma or newline
* separated list.
*/
public void setWelcomeFiles(String welcomeFileNames)
{
StringTokenizer st = new StringTokenizer(welcomeFileNames, "\n,");
while (st.hasMoreTokens())
{
welcomeFiles.add(st.nextToken());
}
}
/**
* Does the page normalizer include query strings in it's definition of
* pages?
* @param normalizeIncludesQueryString The new value
*/
public void setNormalizeIncludesQueryString(boolean normalizeIncludesQueryString)
{
this.normalizeIncludesQueryString = normalizeIncludesQueryString;
}
/**
* @param servletContext the servletContext to set
*/
public void setServletContext(ServletContext servletContext)
{
this.servletContext = servletContext;
}
/**
* We need one of these to do the init process.
*/
private ServletContext servletContext = null;
/**
* Does the page normalizer include query strings in it's definition of
* pages?
*/
protected boolean normalizeIncludesQueryString = false;
/**
* How we create new documents
*/
private static DocumentBuilderFactory buildFactory = null;
/**
* The lock to prevent 2 things from calling init at the same time
*/
protected static final Object initLock = new Object();
/**
* The list of filename components to strip to normalize a filename
*/
private List<String> welcomeFiles;
/**
* The log stream
*/
private static final Log log = LogFactory.getLog(DefaultPageNormalizer.class);
}