org.mycore.common.xml.MCRURIResolverFilter Maven / Gradle / Ivy
/*
* This file is part of *** M y C o R e ***
* See http://www.mycore.de/ for details.
*
* MyCoRe 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 3 of the License, or
* (at your option) any later version.
*
* MyCoRe 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 MyCoRe. If not, see > uriList = ThreadLocal.withInitial(MyLinkedList::new);
/**
* adds debug information from MCRURIResolver to Servlet output.
*
* The information includes all URIs resolved by MCRURIResolver by the
* current request. The filter is triggered by the log4j statement of the
* MCRURIResolver. To switch it on set the logger to DEBUG level.
*
* @see javax.servlet.Filter#doFilter(javax.servlet.ServletRequest,
* javax.servlet.ServletResponse, javax.servlet.FilterChain)
*/
public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain) throws IOException,
ServletException {
/*
* isDebugEnabled() may return a different value when called a second
* time. Since we initialize things in the first block, we need to make
* sure to visit the second block only if we visited the first block,
* too.
*/
final boolean debugEnabled = LOGGER.isDebugEnabled();
if (!debugEnabled) {
//do not filter...
filterChain.doFilter(request, response);
} else {
MyResponseWrapper wrapper = new MyResponseWrapper((HttpServletResponse) response);
// process request
filterChain.doFilter(request, wrapper);
final String origOutput = wrapper.toString();
final String characterEncoding = wrapper.getCharacterEncoding();
if (!uriList.get().isEmpty() && origOutput.length() > 0
&& (response.getContentType().contains("text/html")
|| response.getContentType().contains("text/xml"))) {
final String insertString = "\n";
final byte[] insertBytes = insertString.getBytes(characterEncoding);
response.setContentLength(origOutput.getBytes(characterEncoding).length + insertBytes.length);
int pos = getInsertPosition(origOutput);
try (ServletOutputStream out = response.getOutputStream()) {
out.write(origOutput.substring(0, pos).getBytes(characterEncoding));
out.write(insertBytes);
out.write(origOutput.substring(pos).getBytes(characterEncoding));
// delete debuglist
uriList.remove();
LOGGER.debug("end filter: {}", origOutput.substring(origOutput.length() - 10));
}
} else {
LOGGER.debug("Sending original response");
byte[] byteArray = wrapper.output.toByteArray();
if (byteArray.length > 0) {
try (ServletOutputStream out = response.getOutputStream()) {
out.write(byteArray);
}
}
}
}
}
private int getInsertPosition(final String origOutput) {
// if html document, before head-tag
int pos = origOutput.indexOf("");
if (pos < 0) {
// for xml output, after
pos = origOutput.indexOf("?>") + 2;
}
if (pos < 2) {
// for the rest
pos = 0;
}
return pos;
}
/*
* (non-Javadoc)
*
* @see javax.servlet.Filter#destroy()
*/
public void destroy() {
// nothing to be done so far
}
/*
* (non-Javadoc)
*
* @see javax.servlet.Filter#init(javax.servlet.FilterConfig)
*/
public void init(FilterConfig arg0) throws ServletException {
// no inititalization parameters required so far
}
/**
* LinkedList with overwritten toString() method.
*
* @author Thomas Scheffler (yagee)
*/
private static class MyLinkedList extends LinkedList {
private static final long serialVersionUID = -2602420461572432380L;
@Override
public String toString() {
StringBuilder buf = new StringBuilder("The following includes where resolved by MCRURIResolver:\n\n");
for (String obj : this) {
buf.append(obj);
buf.append('\n');
}
buf.deleteCharAt(buf.length() - 1);
return buf.toString();
}
}
/**
* wrapper arround the servlet response to change the output afterwards.
*
* @author Thomas Scheffler (yagee)
*/
private static class MyResponseWrapper extends HttpServletResponseWrapper {
private ByteArrayOutputStream output;
@Override
public String toString() {
try {
return output.toString(getCharacterEncoding());
} catch (UnsupportedEncodingException e) {
LOGGER.error("Fall back to DEFAULT encoding.");
try {
return output.toString(Charset.defaultCharset().name());
} catch (UnsupportedEncodingException neverThrown) {
throw new RuntimeException(neverThrown);
}
}
}
MyResponseWrapper(HttpServletResponse response) {
super(response);
output = new ByteArrayOutputStream(16 * 1024);
}
@Override
public PrintWriter getWriter() {
return new PrintWriter(new OutputStreamWriter(output, Charset.forName(getCharacterEncoding())));
}
@Override
public ServletOutputStream getOutputStream() throws IOException {
return new MyServletOutputStream();
}
@Override
public String getCharacterEncoding() {
final String encoding = super.getCharacterEncoding();
LOGGER.debug("Character Encoding: {}", encoding);
return encoding;
}
private class MyServletOutputStream extends ServletOutputStream {
@Override
public void print(String arg0) throws IOException {
output.write(arg0.getBytes(getResponse().getCharacterEncoding()));
}
@Override
public void write(int b) throws IOException {
output.write(b);
}
@Override
public boolean isReady() {
return true;
}
@Override
public void setWriteListener(WriteListener writeListener) {
//isReady() is always ready
}
}
}
}