src/main/java/org/apache/sling/engine/impl/DefaultErrorHandler.java - sling-org-apache-sling-engine - Git at Google

 /*
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
  * regarding copyright ownership.  The ASF licenses this file
  * to you 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.apache.sling.engine.impl;

 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;

 import java.io.IOException;
 import java.io.PrintWriter;

 import org.apache.sling.api.SlingHttpServletRequest;
 import org.apache.sling.api.SlingHttpServletResponse;
 import org.apache.sling.api.request.RequestProgressTracker;
 import org.apache.sling.api.request.ResponseUtil;
 import org.apache.sling.api.servlets.ErrorHandler;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;

 import static org.apache.sling.api.SlingConstants.ERROR_REQUEST_URI;
 import static org.apache.sling.api.SlingConstants.ERROR_SERVLET_NAME;

 /**
  * The <code>DefaultErrorHandler</code> is used by the
  * {@link SlingRequestProcessorImpl} for error handling. It works
  * in combination with the error filter chain. If a {@link ErrorHandler} service
  * is registered, the actual response generated is delegated to that service.
  */
 public class DefaultErrorHandler implements ErrorHandler {

     /** default log */
     private final Logger log = LoggerFactory.getLogger(getClass());

     private volatile String serverInfo = ProductInfoProvider.PRODUCT_NAME;

     /** Use this if not null, and if that fails output a report about that failure */
     private volatile ErrorHandler delegate;

     void setServerInfo(final String serverInfo) {
         this.serverInfo = (serverInfo != null) ? serverInfo : ProductInfoProvider.PRODUCT_NAME;
     }

     public void setDelegate(final ErrorHandler eh) {
         delegate = eh;
     }

     private void delegateFailed(
             int originalStatus,
             String originalMessage,
             Throwable t,
             HttpServletRequest request,
             HttpServletResponse response)
             throws IOException {
         // don't include Throwable in the response, gives too much information
         final String m = "Error handler failed:" + t.getClass().getName();
         log.error(m, t);

         if (response.isCommitted()) {
             log.warn("handleError: Response already committed; cannot send error " + originalStatus + " : "
                     + originalMessage);
             return;
         }
         // reset the response to clear headers and body
         // the error filters are NOT called in this edge case
         response.reset();
         sendError(originalStatus, originalMessage, null, request, response);
     }

     // ---------- ErrorHandler interface (default implementation) --------------

     /**
      * Backend implementation of the HttpServletResponse.sendError methods.
      * <p>
      * This implementation resets the response before sending back a
      * standardized response which just conveys the status, the message (either
      * provided or a message derived from the status code), and server
      * information.
      * <p>
      * This method logs error and does not write back and response data if the
      * response has already been committed.
      */
     @Override
     public void handleError(
             final int status,
             String message,
             final SlingHttpServletRequest request,
             final SlingHttpServletResponse response)
             throws IOException {
         // If we have a delegate let it handle the error
         if (delegate != null) {
             try {
                 delegate.handleError(status, message, request, response);
             } catch (final Exception e) {
                 delegateFailed(status, message, e, request, response);
             }
             return;
         }

         if (message == null) {
             message = "HTTP ERROR:" + String.valueOf(status);
         } else {
             message = "HTTP ERROR:" + status + " - " + message;
         }

         sendError(status, message, null, request, response);
     }

     /**
      * Backend implementation of handling uncaught throwables.
      * <p>
      * This implementation resets the response before sending back a
      * standardized response which just conveys the status as 500/INTERNAL
      * SERVER ERROR, the message from the throwable, the stacktrace, and server
      * information.
      * <p>
      * This method logs error and does not write back and response data if the
      * response has already been committed.
      */
     @Override
     public void handleError(
             final Throwable throwable, final SlingHttpServletRequest request, final SlingHttpServletResponse response)
             throws IOException {
         final int status = HttpServletResponse.SC_INTERNAL_SERVER_ERROR;
         // If we have a delegate let it handle the error
         if (delegate != null) {
             try {
                 delegate.handleError(throwable, request, response);
             } catch (final Exception e) {
                 delegateFailed(status, throwable.toString(), e, request, response);
             }
             return;
         }

         sendError(status, throwable.getMessage(), throwable, request, response);
     }

     private void sendError(
             final int status,
             final String message,
             final Throwable throwable,
             final HttpServletRequest request,
             final HttpServletResponse response)
             throws IOException {
         // error situation
         final String servletName = (String) request.getAttribute(ERROR_SERVLET_NAME);
         String requestURI = (String) request.getAttribute(ERROR_REQUEST_URI);
         if (requestURI == null) {
             requestURI = request.getRequestURI();
         }

         // set the status, content type and encoding
         response.setStatus(status);
         response.setContentType("text/html; charset=UTF-8");

         final PrintWriter pw = response.getWriter();
         pw.print("<html><head><title>");
         if (message == null) {
             pw.print("Internal error");
         } else {
             pw.print(ResponseUtil.escapeXml(message));
         }
         pw.println("</title></head><body><h1>");
         if (throwable != null) {
             pw.println(ResponseUtil.escapeXml(throwable.toString()));
         } else if (message != null) {
             pw.println(ResponseUtil.escapeXml(message));
         } else {
             pw.println("Internal error (no Exception to report)");
         }
         pw.println("</h1><p>");
         pw.print("RequestURI=");
         pw.println(ResponseUtil.escapeXml(request.getRequestURI()));
         if (servletName != null) {
             pw.println("</p><p>Servlet=");
             pw.println(ResponseUtil.escapeXml(servletName));
         }
         pw.println("</p>");

         if (throwable != null) {
             final PrintWriter escapingWriter = new PrintWriter(ResponseUtil.getXmlEscapingWriter(pw));
             pw.println("<h3>Exception stacktrace:</h3>");
             pw.println("<pre>");
             pw.flush();
             throwable.printStackTrace(escapingWriter);
             escapingWriter.flush();
             pw.println("</pre>");

             final RequestProgressTracker tracker = ((SlingHttpServletRequest) request).getRequestProgressTracker();
             pw.println("<h3>Request Progress:</h3>");
             pw.println("<pre>");
             pw.flush();
             tracker.dump(new PrintWriter(escapingWriter));
             escapingWriter.flush();
             pw.println("</pre>");
         }

         pw.println("<hr /><address>");
         pw.println(ResponseUtil.escapeXml(serverInfo));
         pw.println("</address></body></html>");

         // commit the response
         response.flushBuffer();
         // close the response (SLING-2724)
         pw.close();
     }
 }
	/*
	* Licensed to the Apache Software Foundation (ASF) under one
	* or more contributor license agreements. See the NOTICE file
	* distributed with this work for additional information
	* regarding copyright ownership. The ASF licenses this file
	* to you 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.apache.sling.engine.impl;

	import javax.servlet.http.HttpServletRequest;
	import javax.servlet.http.HttpServletResponse;

	import java.io.IOException;
	import java.io.PrintWriter;

	import org.apache.sling.api.SlingHttpServletRequest;
	import org.apache.sling.api.SlingHttpServletResponse;
	import org.apache.sling.api.request.RequestProgressTracker;
	import org.apache.sling.api.request.ResponseUtil;
	import org.apache.sling.api.servlets.ErrorHandler;
	import org.slf4j.Logger;
	import org.slf4j.LoggerFactory;

	import static org.apache.sling.api.SlingConstants.ERROR_REQUEST_URI;
	import static org.apache.sling.api.SlingConstants.ERROR_SERVLET_NAME;

	/**
	* The <code>DefaultErrorHandler</code> is used by the
	* {@link SlingRequestProcessorImpl} for error handling. It works
	* in combination with the error filter chain. If a {@link ErrorHandler} service
	* is registered, the actual response generated is delegated to that service.
	*/
	public class DefaultErrorHandler implements ErrorHandler {

	/** default log */
	private final Logger log = LoggerFactory.getLogger(getClass());

	private volatile String serverInfo = ProductInfoProvider.PRODUCT_NAME;

	/** Use this if not null, and if that fails output a report about that failure */
	private volatile ErrorHandler delegate;

	void setServerInfo(final String serverInfo) {
	this.serverInfo = (serverInfo != null) ? serverInfo : ProductInfoProvider.PRODUCT_NAME;
	}

	public void setDelegate(final ErrorHandler eh) {
	delegate = eh;
	}

	private void delegateFailed(
	int originalStatus,
	String originalMessage,
	Throwable t,
	HttpServletRequest request,
	HttpServletResponse response)
	throws IOException {
	// don't include Throwable in the response, gives too much information
	final String m = "Error handler failed:" + t.getClass().getName();
	log.error(m, t);

	if (response.isCommitted()) {
	log.warn("handleError: Response already committed; cannot send error " + originalStatus + " : "
	+ originalMessage);
	return;
	}
	// reset the response to clear headers and body
	// the error filters are NOT called in this edge case
	response.reset();
	sendError(originalStatus, originalMessage, null, request, response);
	}

	// ---------- ErrorHandler interface (default implementation) --------------

	/**
	* Backend implementation of the HttpServletResponse.sendError methods.
	* <p>
	* This implementation resets the response before sending back a
	* standardized response which just conveys the status, the message (either
	* provided or a message derived from the status code), and server
	* information.
	* <p>
	* This method logs error and does not write back and response data if the
	* response has already been committed.
	*/
	@Override
	public void handleError(
	final int status,
	String message,
	final SlingHttpServletRequest request,
	final SlingHttpServletResponse response)
	throws IOException {
	// If we have a delegate let it handle the error
	if (delegate != null) {
	try {
	delegate.handleError(status, message, request, response);
	} catch (final Exception e) {
	delegateFailed(status, message, e, request, response);
	}
	return;
	}

	if (message == null) {
	message = "HTTP ERROR:" + String.valueOf(status);
	} else {
	message = "HTTP ERROR:" + status + " - " + message;
	}

	sendError(status, message, null, request, response);
	}

	/**
	* Backend implementation of handling uncaught throwables.
	* <p>
	* This implementation resets the response before sending back a
	* standardized response which just conveys the status as 500/INTERNAL
	* SERVER ERROR, the message from the throwable, the stacktrace, and server
	* information.
	* <p>
	* This method logs error and does not write back and response data if the
	* response has already been committed.
	*/
	@Override
	public void handleError(
	final Throwable throwable, final SlingHttpServletRequest request, final SlingHttpServletResponse response)
	throws IOException {
	final int status = HttpServletResponse.SC_INTERNAL_SERVER_ERROR;
	// If we have a delegate let it handle the error
	if (delegate != null) {
	try {
	delegate.handleError(throwable, request, response);
	} catch (final Exception e) {
	delegateFailed(status, throwable.toString(), e, request, response);
	}
	return;
	}

	sendError(status, throwable.getMessage(), throwable, request, response);
	}

	private void sendError(
	final int status,
	final String message,
	final Throwable throwable,
	final HttpServletRequest request,
	final HttpServletResponse response)
	throws IOException {
	// error situation
	final String servletName = (String) request.getAttribute(ERROR_SERVLET_NAME);
	String requestURI = (String) request.getAttribute(ERROR_REQUEST_URI);
	if (requestURI == null) {
	requestURI = request.getRequestURI();
	}

	// set the status, content type and encoding
	response.setStatus(status);
	response.setContentType("text/html; charset=UTF-8");

	final PrintWriter pw = response.getWriter();
	pw.print("<html><head><title>");
	if (message == null) {
	pw.print("Internal error");
	} else {
	pw.print(ResponseUtil.escapeXml(message));
	}
	pw.println("</title></head><body><h1>");
	if (throwable != null) {
	pw.println(ResponseUtil.escapeXml(throwable.toString()));
	} else if (message != null) {
	pw.println(ResponseUtil.escapeXml(message));
	} else {
	pw.println("Internal error (no Exception to report)");
	}
	pw.println("</h1><p>");
	pw.print("RequestURI=");
	pw.println(ResponseUtil.escapeXml(request.getRequestURI()));
	if (servletName != null) {
	pw.println("</p><p>Servlet=");
	pw.println(ResponseUtil.escapeXml(servletName));
	}
	pw.println("</p>");

	if (throwable != null) {
	final PrintWriter escapingWriter = new PrintWriter(ResponseUtil.getXmlEscapingWriter(pw));
	pw.println("<h3>Exception stacktrace:</h3>");
	pw.println("<pre>");
	pw.flush();
	throwable.printStackTrace(escapingWriter);
	escapingWriter.flush();
	pw.println("</pre>");

	final RequestProgressTracker tracker = ((SlingHttpServletRequest) request).getRequestProgressTracker();
	pw.println("<h3>Request Progress:</h3>");
	pw.println("<pre>");
	pw.flush();
	tracker.dump(new PrintWriter(escapingWriter));
	escapingWriter.flush();
	pw.println("</pre>");
	}

	pw.println("<hr /><address>");
	pw.println(ResponseUtil.escapeXml(serverInfo));
	pw.println("</address></body></html>");

	// commit the response
	response.flushBuffer();
	// close the response (SLING-2724)
	pw.close();
	}
	}