/**
* Attempts to send an internal server error HTTP error, if possible. Otherwise simply pushes the
* exception message to the output stream.
*
* @param message Message to be printed to the logger and to the output stream.
* @param t Exception that caused the error.
*/
protected void filterError(String message, Throwable t) {
log.error("XSLT filter error: " + message, t);
if (false == origResponse.isCommitted()) {
// Reset the buffer and previous status code.
origResponse.reset();
origResponse.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
origResponse.setContentType("text/html; charset=UTF-8");
}
// Response committed. Just push the error to the output stream.
try {
final OutputStream os = origResponse.getOutputStream();
final PrintWriter osw = new PrintWriter(new OutputStreamWriter(os, "iso8859-1"));
osw.write("<html><body><!-- " + XSLTFilterConstants.ERROR_TOKEN + " -->");
osw.write("<h1 style=\"color: red; margin-top: 1em;\">");
osw.write("Internal server exception");
osw.write("</h1>");
osw.write("<b>URI</b>: " + origRequest.getRequestURI() + "\n<br/><br/>");
serializeException(osw, t);
if (t instanceof ServletException && ((ServletException) t).getRootCause() != null) {
osw.write("<br/><br/><h2>ServletException root cause:</h2>");
serializeException(osw, ((ServletException) t).getRootCause());
}
osw.write("</body></html>");
osw.flush();
} catch (IOException e) {
// Not much to do in such case (connection broken most likely).
log.debug("Filter error could not be returned to client.");
}
}
/**
* Return the character output stream for this response. This is either the original stream or a
* buffered stream.
*
* @exception IllegalStateException Thrown when byte stream has been already initialized ({@link
* #getOutputStream()}).
*/
public PrintWriter getWriter() throws IOException {
if (stream != null) {
throw new IllegalStateException(
"Byte stream has been already initialized. Use streams consequently.");
}
if (writer != null) {
return writer;
}
if (passthrough) {
writer = this.origResponse.getWriter();
return writer;
}
/*
* TODO: The character encoding should be extracted in {@link #setContentType()},
* saved somewhere locally and used here. The response's character encoding may be
* different (depends on the stylesheet).
*/
final String charEnc = origResponse.getCharacterEncoding();
this.stream = new DeferredOutputStream();
if (charEnc != null) {
writer = new PrintWriter(new OutputStreamWriter(stream, charEnc));
} else {
writer = new PrintWriter(stream);
}
return writer;
}
/** We override this method to detect XML data streams. */
public void setContentType(String contentType) {
// Check if XSLT processing has been suppressed for this request.
final boolean processingSuppressed = processingSuppressed(origRequest);
if (processingSuppressed) {
// Processing is suppressed.
log.debug("XSLT processing disabled for the request.");
}
if (!processingSuppressed
&& (contentType.startsWith("text/xml") || contentType.startsWith("application/xml"))) {
/*
* We have an XML data stream. Set the real response to proper content type.
* TODO: Should we make the encoding a configurable setting?
*/
origResponse.setContentType("text/html; charset=UTF-8");
} else {
/*
* The input is something we won't process anyway, so simply passthrough all
* data directly to the output stream.
*/
if (!processingSuppressed) {
log.info(
"Content type is not text/xml or application/xml (" + contentType + "), passthrough.");
}
origResponse.setContentType(contentType);
passthrough = true;
// If the output stream is already initialized, passthrough everything.
if (stream != null && stream instanceof DeferredOutputStream) {
try {
((DeferredOutputStream) stream).passthrough(origResponse.getOutputStream());
} catch (IOException e) {
((DeferredOutputStream) stream).setExceptionOnNext(e);
}
}
}
}
/**
* Return the byte output stream for this response. This is either the original stream or a
* buffered stream.
*
* @exception IllegalStateException Thrown when character stream has been already initialized
* ({@link #getWriter()}).
*/
public ServletOutputStream getOutputStream() throws IOException {
if (writer != null) {
throw new IllegalStateException(
"Character stream has been already initialized. Use streams consequently.");
}
if (stream != null) {
return stream;
}
if (passthrough) {
stream = origResponse.getOutputStream();
} else {
stream = new DeferredOutputStream();
}
return stream;
}
/**
* This method must be invoked at the end of processing. The streams are closed and their content
* is analyzed. Actual XSLT processing takes place here.
*/
@SuppressWarnings("unchecked")
void finishResponse() throws IOException {
if (writer != null) {
writer.close();
} else {
if (stream != null) stream.close();
}
/*
* If we're not in passthrough mode, then we need to finalize XSLT transformation.
*/
if (false == passthrough) {
if (stream != null) {
final byte[] bytes = ((DeferredOutputStream) stream).getBytes();
final boolean processingSuppressed =
(origRequest.getAttribute(XSLTFilterConstants.NO_XSLT_PROCESSING) != null)
| (origRequest.getParameter(XSLTFilterConstants.NO_XSLT_PROCESSING) != null);
if (processingSuppressed) {
// Just copy the buffered data to the output directly.
final OutputStream os = origResponse.getOutputStream();
os.write(bytes);
os.close();
} else {
// Otherwise apply XSLT transformation to it.
try {
processWithXslt(
bytes,
(Map<String, Object>) origRequest.getAttribute(XSLTFilterConstants.XSLT_PARAMS_MAP),
origResponse);
} catch (TransformerException e) {
final Throwable t = unwrapCause(e);
if (t instanceof IOException) {
throw (IOException) t;
}
filterError("Error applying stylesheet.", e);
}
}
}
}
}
