lib/jetty/org/eclipse/jetty/server/handler/ErrorHandler.java

   1 //
   2 //  ========================================================================
   3 //  Copyright (c) 1995-2016 Mort Bay Consulting Pty. Ltd.
   4 //  ------------------------------------------------------------------------
   5 //  All rights reserved. This program and the accompanying materials
   6 //  are made available under the terms of the Eclipse Public License v1.0
   7 //  and Apache License v2.0 which accompanies this distribution.
   8 //
   9 //      The Eclipse Public License is available at
  10 //      http://www.eclipse.org/legal/epl-v10.html
  11 //
  12 //      The Apache License v2.0 is available at
  13 //      http://www.opensource.org/licenses/apache2.0.php
  14 //
  15 //  You may elect to redistribute this code under either of these licenses.
  16 //  ========================================================================
  17 //
  18
  19 package org.eclipse.jetty.server.handler;
  20
  21 import java.io.IOException;
  22 import java.io.PrintWriter;
  23 import java.io.StringWriter;
  24 import java.io.Writer;
  25 import java.nio.ByteBuffer;
  26
  27 import javax.servlet.ServletException;
  28 import javax.servlet.http.HttpServletRequest;
  29 import javax.servlet.http.HttpServletResponse;
  30
  31 import org.eclipse.jetty.http.HttpFields;
  32 import org.eclipse.jetty.http.HttpHeader;
  33 import org.eclipse.jetty.http.HttpMethod;
  34 import org.eclipse.jetty.http.HttpStatus;
  35 import org.eclipse.jetty.http.MimeTypes;
  36 import org.eclipse.jetty.server.Dispatcher;
  37 import org.eclipse.jetty.server.Request;
  38 import org.eclipse.jetty.server.Response;
  39 import org.eclipse.jetty.server.Server;
  40 import org.eclipse.jetty.util.BufferUtil;
  41 import org.eclipse.jetty.util.ByteArrayISO8859Writer;
  42 import org.eclipse.jetty.util.StringUtil;
  43 import org.eclipse.jetty.util.log.Log;
  44 import org.eclipse.jetty.util.log.Logger;
  45
  46 /* ------------------------------------------------------------ */
  47 /** Handler for Error pages
  48  * An ErrorHandler is registered with {@link ContextHandler#setErrorHandler(ErrorHandler)} or
  49  * {@link org.eclipse.jetty.server.Server#addBean(Object)}.
  50  * It is called by the HttpResponse.sendError method to write a error page via {@link #handle(String, Request, HttpServletRequest, HttpServletResponse)}
  51  * or via {@link #badMessageError(int, String, HttpFields)} for bad requests for which a dispatch cannot be done.
  52  *
  53  */
  54 public class ErrorHandler extends AbstractHandler
  55 {
  56     private static final Logger LOG = Log.getLogger(ErrorHandler.class);
  57     public final static String ERROR_PAGE="org.eclipse.jetty.server.error_page";
  58
  59     boolean _showStacks=true;
  60     boolean _showMessageInTitle=true;
  61     String _cacheControl="must-revalidate,no-cache,no-store";
  62
  63     /* ------------------------------------------------------------ */
  64     /*
  65      * @see org.eclipse.jetty.server.server.Handler#handle(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse, int)
  66      */
  67     @Override
  68     public void handle(String target, Request baseRequest, HttpServletRequest request, HttpServletResponse response) throws IOException
  69     {
  70         String method = request.getMethod();
  71         if (!HttpMethod.GET.is(method) && !HttpMethod.POST.is(method) && !HttpMethod.HEAD.is(method))
  72         {
  73             baseRequest.setHandled(true);
  74             return;
  75         }
  76
  77         if (this instanceof ErrorPageMapper)
  78         {
  79             String error_page=((ErrorPageMapper)this).getErrorPage(request);
  80             if (error_page!=null && request.getServletContext()!=null)
  81             {
  82                 String old_error_page=(String)request.getAttribute(ERROR_PAGE);
  83                 if (old_error_page==null || !old_error_page.equals(error_page))
  84                 {
  85                     request.setAttribute(ERROR_PAGE, error_page);
  86
  87                     Dispatcher dispatcher = (Dispatcher) request.getServletContext().getRequestDispatcher(error_page);
  88                     try
  89                     {
  90                         if(dispatcher!=null)
  91                         {
  92                             dispatcher.error(request, response);
  93                             return;
  94                         }
  95                         LOG.warn("No error page "+error_page);
  96                     }
  97                     catch (ServletException e)
  98                     {
  99                         LOG.warn(Log.EXCEPTION, e);
 100                         return;
 101                     }
 102                 }
 103             }
 104         }
 105
 106         baseRequest.setHandled(true);
 107         response.setContentType(MimeTypes.Type.TEXT_HTML_8859_1.asString());
 108         if (_cacheControl!=null)
 109             response.setHeader(HttpHeader.CACHE_CONTROL.asString(), _cacheControl);
 110         ByteArrayISO8859Writer writer= new ByteArrayISO8859Writer(4096);
 111         String reason=(response instanceof Response)?((Response)response).getReason():null;
 112         handleErrorPage(request, writer, response.getStatus(), reason);
 113         writer.flush();
 114         response.setContentLength(writer.size());
 115         writer.writeTo(response.getOutputStream());
 116         writer.destroy();
 117     }
 118
 119     /* ------------------------------------------------------------ */
 120     protected void handleErrorPage(HttpServletRequest request, Writer writer, int code, String message)
 121         throws IOException
 122     {
 123         writeErrorPage(request, writer, code, message, _showStacks);
 124     }
 125
 126     /* ------------------------------------------------------------ */
 127     protected void writeErrorPage(HttpServletRequest request, Writer writer, int code, String message, boolean showStacks)
 128         throws IOException
 129     {
 130         if (message == null)
 131             message=HttpStatus.getMessage(code);
 132
 133         writer.write("<html>\n<head>\n");
 134         writeErrorPageHead(request,writer,code,message);
 135         writer.write("</head>\n<body>");
 136         writeErrorPageBody(request,writer,code,message,showStacks);
 137         writer.write("\n</body>\n</html>\n");
 138     }
 139
 140     /* ------------------------------------------------------------ */
 141     protected void writeErrorPageHead(HttpServletRequest request, Writer writer, int code, String message)
 142         throws IOException
 143         {
 144         writer.write("<meta http-equiv=\"Content-Type\" content=\"text/html; charset=UTF-8\"/>\n");
 145         writer.write("<title>Error ");
 146         writer.write(Integer.toString(code));
 147
 148         if (_showMessageInTitle)
 149         {
 150             writer.write(' ');
 151             write(writer,message);
 152         }
 153         writer.write("</title>\n");
 154     }
 155
 156     /* ------------------------------------------------------------ */
 157     protected void writeErrorPageBody(HttpServletRequest request, Writer writer, int code, String message, boolean showStacks)
 158         throws IOException
 159     {
 160         String uri= request.getRequestURI();
 161
 162         writeErrorPageMessage(request,writer,code,message,uri);
 163         if (showStacks)
 164             writeErrorPageStacks(request,writer);
 165         writer.write("<hr><i><small>Powered by Jetty://</small></i><hr/>\n");
 166     }
 167
 168     /* ------------------------------------------------------------ */
 169     protected void writeErrorPageMessage(HttpServletRequest request, Writer writer, int code, String message,String uri)
 170     throws IOException
 171     {
 172         writer.write("<h2>HTTP ERROR ");
 173         writer.write(Integer.toString(code));
 174         writer.write("</h2>\n<p>Problem accessing ");
 175         write(writer,uri);
 176         writer.write(". Reason:\n<pre>    ");
 177         write(writer,message);
 178         writer.write("</pre></p>");
 179     }
 180
 181     /* ------------------------------------------------------------ */
 182     protected void writeErrorPageStacks(HttpServletRequest request, Writer writer)
 183         throws IOException
 184     {
 185         Throwable th = (Throwable)request.getAttribute("javax.servlet.error.exception");
 186         while(th!=null)
 187         {
 188             writer.write("<h3>Caused by:</h3><pre>");
 189             StringWriter sw = new StringWriter();
 190             PrintWriter pw = new PrintWriter(sw);
 191             th.printStackTrace(pw);
 192             pw.flush();
 193             write(writer,sw.getBuffer().toString());
 194             writer.write("</pre>\n");
 195
 196             th =th.getCause();
 197         }
 198     }
 199
 200     /* ------------------------------------------------------------ */
 201     /** Bad Message Error body
 202      * <p>Generate a error response body to be sent for a bad message.
 203      * In this case there is something wrong with the request, so either
 204      * a request cannot be built, or it is not safe to build a request.
 205      * This method allows for a simple error page body to be returned
 206      * and some response headers to be set.
 207      * @param status The error code that will be sent
 208      * @param reason The reason for the error code (may be null)
 209      * @param fields The header fields that will be sent with the response.
 210      * @return The content as a ByteBuffer, or null for no body.
 211      */
 212     public ByteBuffer badMessageError(int status, String reason, HttpFields fields)
 213     {
 214         if (reason==null)
 215             reason=HttpStatus.getMessage(status);
 216         fields.put(HttpHeader.CONTENT_TYPE,MimeTypes.Type.TEXT_HTML_8859_1.asString());
 217         return BufferUtil.toBuffer("<h1>Bad Message " + status + "</h1><pre>reason: " + reason + "</pre>");
 218     }
 219
 220     /* ------------------------------------------------------------ */
 221     /** Get the cacheControl.
 222      * @return the cacheControl header to set on error responses.
 223      */
 224     public String getCacheControl()
 225     {
 226         return _cacheControl;
 227     }
 228
 229     /* ------------------------------------------------------------ */
 230     /** Set the cacheControl.
 231      * @param cacheControl the cacheControl header to set on error responses.
 232      */
 233     public void setCacheControl(String cacheControl)
 234     {
 235         _cacheControl = cacheControl;
 236     }
 237
 238     /* ------------------------------------------------------------ */
 239     /**
 240      * @return True if stack traces are shown in the error pages
 241      */
 242     public boolean isShowStacks()
 243     {
 244         return _showStacks;
 245     }
 246
 247     /* ------------------------------------------------------------ */
 248     /**
 249      * @param showStacks True if stack traces are shown in the error pages
 250      */
 251     public void setShowStacks(boolean showStacks)
 252     {
 253         _showStacks = showStacks;
 254     }
 255
 256     /* ------------------------------------------------------------ */
 257     /**
 258      * @param showMessageInTitle if true, the error message appears in page title
 259      */
 260     public void setShowMessageInTitle(boolean showMessageInTitle)
 261     {
 262         _showMessageInTitle = showMessageInTitle;
 263     }
 264
 265
 266     /* ------------------------------------------------------------ */
 267     public boolean getShowMessageInTitle()
 268     {
 269         return _showMessageInTitle;
 270     }
 271
 272     /* ------------------------------------------------------------ */
 273     protected void write(Writer writer,String string)
 274         throws IOException
 275     {
 276         if (string==null)
 277             return;
 278
 279         writer.write(StringUtil.sanitizeXmlString(string));
 280     }
 281
 282     /* ------------------------------------------------------------ */
 283     public interface ErrorPageMapper
 284     {
 285         String getErrorPage(HttpServletRequest request);
 286     }
 287
 288     /* ------------------------------------------------------------ */
 289     public static ErrorHandler getErrorHandler(Server server, ContextHandler context)
 290     {
 291         ErrorHandler error_handler=null;
 292         if (context!=null)
 293             error_handler=context.getErrorHandler();
 294         if (error_handler==null && server!=null)
 295             error_handler = server.getBean(ErrorHandler.class);
 296         return error_handler;
 297     }
 298 }