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

   1 //
   2 //  ========================================================================
   3 //  Copyright (c) 1995-2014 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.log.Log;
  43 import org.eclipse.jetty.util.log.Logger;
  44
  45 /* ------------------------------------------------------------ */
  46 /** Handler for Error pages
  47  * An ErrorHandler is registered with {@link ContextHandler#setErrorHandler(ErrorHandler)} or
  48  * {@link org.eclipse.jetty.server.Server#addBean(Object)}.
  49  * It is called by the HttpResponse.sendError method to write a error page via {@link #handle(String, Request, HttpServletRequest, HttpServletResponse)}
  50  * or via {@link #badMessageError(int, String, HttpFields)} for bad requests for which a dispatch cannot be done.
  51  *
  52  */
  53 public class ErrorHandler extends AbstractHandler
  54 {
  55     private static final Logger LOG = Log.getLogger(ErrorHandler.class);
  56     public final static String ERROR_PAGE="org.eclipse.jetty.server.error_page";
  57
  58     boolean _showStacks=true;
  59     boolean _showMessageInTitle=true;
  60     String _cacheControl="must-revalidate,no-cache,no-store";
  61
  62     /* ------------------------------------------------------------ */
  63     /*
  64      * @see org.eclipse.jetty.server.server.Handler#handle(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse, int)
  65      */
  66     @Override
  67     public void handle(String target, Request baseRequest, HttpServletRequest request, HttpServletResponse response) throws IOException
  68     {
  69         String method = request.getMethod();
  70         if (!HttpMethod.GET.is(method) && !HttpMethod.POST.is(method) && !HttpMethod.HEAD.is(method))
  71         {
  72             baseRequest.setHandled(true);
  73             return;
  74         }
  75
  76         if (this instanceof ErrorPageMapper)
  77         {
  78             String error_page=((ErrorPageMapper)this).getErrorPage(request);
  79             if (error_page!=null && request.getServletContext()!=null)
  80             {
  81                 String old_error_page=(String)request.getAttribute(ERROR_PAGE);
  82                 if (old_error_page==null || !old_error_page.equals(error_page))
  83                 {
  84                     request.setAttribute(ERROR_PAGE, error_page);
  85
  86                     Dispatcher dispatcher = (Dispatcher) request.getServletContext().getRequestDispatcher(error_page);
  87                     try
  88                     {
  89                         if(dispatcher!=null)
  90                         {
  91                             dispatcher.error(request, response);
  92                             return;
  93                         }
  94                         LOG.warn("No error page "+error_page);
  95                     }
  96                     catch (ServletException e)
  97                     {
  98                         LOG.warn(Log.EXCEPTION, e);
  99                         return;
 100                     }
 101                 }
 102             }
 103         }
 104
 105         baseRequest.setHandled(true);
 106         response.setContentType(MimeTypes.Type.TEXT_HTML_8859_1.asString());
 107         if (_cacheControl!=null)
 108             response.setHeader(HttpHeader.CACHE_CONTROL.asString(), _cacheControl);
 109         ByteArrayISO8859Writer writer= new ByteArrayISO8859Writer(4096);
 110         String reason=(response instanceof Response)?((Response)response).getReason():null;
 111         handleErrorPage(request, writer, response.getStatus(), reason);
 112         writer.flush();
 113         response.setContentLength(writer.size());
 114         writer.writeTo(response.getOutputStream());
 115         writer.destroy();
 116     }
 117
 118     /* ------------------------------------------------------------ */
 119     protected void handleErrorPage(HttpServletRequest request, Writer writer, int code, String message)
 120         throws IOException
 121     {
 122         writeErrorPage(request, writer, code, message, _showStacks);
 123     }
 124
 125     /* ------------------------------------------------------------ */
 126     protected void writeErrorPage(HttpServletRequest request, Writer writer, int code, String message, boolean showStacks)
 127         throws IOException
 128     {
 129         if (message == null)
 130             message=HttpStatus.getMessage(code);
 131
 132         writer.write("<html>\n<head>\n");
 133         writeErrorPageHead(request,writer,code,message);
 134         writer.write("</head>\n<body>");
 135         writeErrorPageBody(request,writer,code,message,showStacks);
 136         writer.write("\n</body>\n</html>\n");
 137     }
 138
 139     /* ------------------------------------------------------------ */
 140     protected void writeErrorPageHead(HttpServletRequest request, Writer writer, int code, String message)
 141         throws IOException
 142         {
 143         writer.write("<meta http-equiv=\"Content-Type\" content=\"text/html; charset=UTF-8\"/>\n");
 144         writer.write("<title>Error ");
 145         writer.write(Integer.toString(code));
 146
 147         if (_showMessageInTitle)
 148         {
 149             writer.write(' ');
 150             write(writer,message);
 151         }
 152         writer.write("</title>\n");
 153     }
 154
 155     /* ------------------------------------------------------------ */
 156     protected void writeErrorPageBody(HttpServletRequest request, Writer writer, int code, String message, boolean showStacks)
 157         throws IOException
 158     {
 159         String uri= request.getRequestURI();
 160
 161         writeErrorPageMessage(request,writer,code,message,uri);
 162         if (showStacks)
 163             writeErrorPageStacks(request,writer);
 164         writer.write("<hr><i><small>Powered by Jetty://</small></i><hr/>\n");
 165     }
 166
 167     /* ------------------------------------------------------------ */
 168     protected void writeErrorPageMessage(HttpServletRequest request, Writer writer, int code, String message,String uri)
 169     throws IOException
 170     {
 171         writer.write("<h2>HTTP ERROR ");
 172         writer.write(Integer.toString(code));
 173         writer.write("</h2>\n<p>Problem accessing ");
 174         write(writer,uri);
 175         writer.write(". Reason:\n<pre>    ");
 176         write(writer,message);
 177         writer.write("</pre></p>");
 178     }
 179
 180     /* ------------------------------------------------------------ */
 181     protected void writeErrorPageStacks(HttpServletRequest request, Writer writer)
 182         throws IOException
 183     {
 184         Throwable th = (Throwable)request.getAttribute("javax.servlet.error.exception");
 185         while(th!=null)
 186         {
 187             writer.write("<h3>Caused by:</h3><pre>");
 188             StringWriter sw = new StringWriter();
 189             PrintWriter pw = new PrintWriter(sw);
 190             th.printStackTrace(pw);
 191             pw.flush();
 192             write(writer,sw.getBuffer().toString());
 193             writer.write("</pre>\n");
 194
 195             th =th.getCause();
 196         }
 197     }
 198
 199     /* ------------------------------------------------------------ */
 200     /** Bad Message Error body
 201      * <p>Generate a error response body to be sent for a bad message.
 202      * In this case there is something wrong with the request, so either
 203      * a request cannot be built, or it is not safe to build a request.
 204      * This method allows for a simple error page body to be returned
 205      * and some response headers to be set.
 206      * @param status The error code that will be sent
 207      * @param reason The reason for the error code (may be null)
 208      * @param fields The header fields that will be sent with the response.
 209      * @return The content as a ByteBuffer, or null for no body.
 210      */
 211     public ByteBuffer badMessageError(int status, String reason, HttpFields fields)
 212     {
 213         if (reason==null)
 214             reason=HttpStatus.getMessage(status);
 215         fields.put(HttpHeader.CONTENT_TYPE,MimeTypes.Type.TEXT_HTML_8859_1.asString());
 216         return BufferUtil.toBuffer("<h1>Bad Message " + status + "</h1><pre>reason: " + reason + "</pre>");
 217     }
 218
 219     /* ------------------------------------------------------------ */
 220     /** Get the cacheControl.
 221      * @return the cacheControl header to set on error responses.
 222      */
 223     public String getCacheControl()
 224     {
 225         return _cacheControl;
 226     }
 227
 228     /* ------------------------------------------------------------ */
 229     /** Set the cacheControl.
 230      * @param cacheControl the cacheControl header to set on error responses.
 231      */
 232     public void setCacheControl(String cacheControl)
 233     {
 234         _cacheControl = cacheControl;
 235     }
 236
 237     /* ------------------------------------------------------------ */
 238     /**
 239      * @return True if stack traces are shown in the error pages
 240      */
 241     public boolean isShowStacks()
 242     {
 243         return _showStacks;
 244     }
 245
 246     /* ------------------------------------------------------------ */
 247     /**
 248      * @param showStacks True if stack traces are shown in the error pages
 249      */
 250     public void setShowStacks(boolean showStacks)
 251     {
 252         _showStacks = showStacks;
 253     }
 254
 255     /* ------------------------------------------------------------ */
 256     /**
 257      * @param showMessageInTitle if true, the error message appears in page title
 258      */
 259     public void setShowMessageInTitle(boolean showMessageInTitle)
 260     {
 261         _showMessageInTitle = showMessageInTitle;
 262     }
 263
 264
 265     /* ------------------------------------------------------------ */
 266     public boolean getShowMessageInTitle()
 267     {
 268         return _showMessageInTitle;
 269     }
 270
 271     /* ------------------------------------------------------------ */
 272     protected void write(Writer writer,String string)
 273         throws IOException
 274     {
 275         if (string==null)
 276             return;
 277
 278         for (int i=0;i<string.length();i++)
 279         {
 280             char c=string.charAt(i);
 281
 282             switch(c)
 283             {
 284                 case '&' :
 285                     writer.write("&amp;");
 286                     break;
 287                 case '<' :
 288                     writer.write("&lt;");
 289                     break;
 290                 case '>' :
 291                     writer.write("&gt;");
 292                     break;
 293
 294                 default:
 295                     if (Character.isISOControl(c) && !Character.isWhitespace(c))
 296                         writer.write('?');
 297                     else
 298                         writer.write(c);
 299             }
 300         }
 301     }
 302
 303     /* ------------------------------------------------------------ */
 304     public interface ErrorPageMapper
 305     {
 306         String getErrorPage(HttpServletRequest request);
 307     }
 308
 309     /* ------------------------------------------------------------ */
 310     public static ErrorHandler getErrorHandler(Server server, ContextHandler context)
 311     {
 312         ErrorHandler error_handler=null;
 313         if (context!=null)
 314             error_handler=context.getErrorHandler();
 315         if (error_handler==null && server!=null)
 316             error_handler = server.getBean(ErrorHandler.class);
 317         return error_handler;
 318     }
 319 }