Java tutorial
/* * Copyright (c) 1998-2012 Caucho Technology -- all rights reserved * * This file is part of Resin(R) Open Source * * Each copy or derived work must preserve the copyright notice and this * notice unmodified. * * Resin Open Source 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 2 of the License, or * (at your option) any later version. * * Resin Open Source 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, or any warranty * of NON-INFRINGEMENT. See the GNU General Public License for more * details. * * You should have received a copy of the GNU General Public License * along with Resin Open Source; if not, write to the * * Free Software Foundation, Inc. * 59 Temple Place, Suite 330 * Boston, MA 02111-1307 USA * * @author Scott Ferguson */ package org.ireland.jnetty.webapp; import java.io.CharArrayWriter; import java.io.IOException; import java.io.OutputStreamWriter; import java.io.PrintWriter; import java.util.HashMap; import java.util.Locale; import org.apache.commons.logging.LogFactory; import org.apache.commons.logging.Log; import javax.servlet.AsyncContext; import javax.servlet.RequestDispatcher; import javax.servlet.ServletException; import javax.servlet.ServletRequest; import javax.servlet.ServletRequestWrapper; import javax.servlet.ServletResponse; import javax.servlet.UnavailableException; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import com.caucho.VersionFactory; import com.caucho.config.LineException; import com.caucho.env.shutdown.ShutdownSystem; import com.caucho.i18n.CharacterEncoding; import com.caucho.java.LineMap; import com.caucho.java.LineMapException; import com.caucho.java.ScriptStackTrace; import com.caucho.server.dispatch.BadRequestException; import com.caucho.server.host.Host; import com.caucho.server.http.CauchoRequest; import com.caucho.server.http.CauchoResponse; import com.caucho.server.http.HttpServletRequestImpl; import com.caucho.server.http.HttpServletResponseImpl; import com.caucho.util.CharBuffer; import com.caucho.util.CompileException; import com.caucho.util.CurrentTime; import com.caucho.util.DisplayableException; import com.caucho.util.LineCompileException; import com.caucho.util.QDate; import com.caucho.vfs.ClientDisconnectException; import com.caucho.vfs.Encoding; import com.caucho.vfs.Vfs; /** * Represents the final servlet in a filter chain. */ public class ErrorPageManager { private static final Log log = LogFactory.getLog(ErrorPageManager.class.getName()); private static final boolean debug = log.isDebugEnabled(); public static final char[] MSIE_PADDING; public static String JSP_EXCEPTION = "javax.servlet.jsp.jspException"; public static String SHUTDOWN = "com.caucho.shutdown"; private final Host _host; private final WebApp _webApp; private HashMap<Object, String> _errorPageMap = new HashMap<Object, String>(); private String _defaultLocation; /** * Create error page manager. */ public ErrorPageManager(WebApp webApp) { this(null, webApp); } /** * Create error page manager. */ public ErrorPageManager(Host host, WebApp app) { _webApp = app; _host = host; } /** * Adds an error page. */ public void addErrorPage(String exceptionType, String location) { _errorPageMap.put(exceptionType, location); } /** * Adds an error page. */ public void addErrorPage(int errorCode, String location) { _errorPageMap.put(errorCode, location); } /** * ? * * @param location */ public void setDefaultLocation(String location) { this._defaultLocation = location; } /** * Returns true if we should return a development-friendly error page. */ protected boolean isDevelopmentModeErrorPage() { return true; } /** * Displays a parse error. */ public void sendServletError(Throwable e, ServletRequest req, ServletResponse res) throws IOException { try { sendServletErrorImpl(e, req, res); } finally { if (res instanceof CauchoResponse) ((CauchoResponse) res).close(); } } public void sendServletErrorImpl(Throwable e, ServletRequest req, ServletResponse res) throws IOException { HttpServletResponse response = (HttpServletResponse) res; HttpServletRequest request = (HttpServletRequest) req; Throwable rootExn = e; Throwable errorPageExn = null; LineMap lineMap = null; try { response.reset(); } catch (IllegalStateException e1) { } if (req.isAsyncStarted()) { AsyncContext async = req.getAsyncContext(); if (async != null) async.complete(); } if (response instanceof HttpServletResponseImpl) { HttpServletResponseImpl resFacade = (HttpServletResponseImpl) response; resFacade.killCache(); resFacade.setNoCache(true); } if (rootExn instanceof ClientDisconnectException) throw (ClientDisconnectException) rootExn; String location = null; String title = "500 Servlet Exception"; boolean isBadRequest = false; boolean doStackTrace = true; boolean isCompileException = false; boolean isServletException = false; Throwable compileException = null; String lineMessage = null; boolean lookupErrorPage = true; while (true) { if (rootExn instanceof LineMapException) lineMap = ((LineMapException) rootExn).getLineMap(); if (lookupErrorPage) { errorPageExn = rootExn; } if (rootExn instanceof DisplayableException) { doStackTrace = false; isCompileException = true; if (compileException == null) compileException = rootExn; } else if (rootExn instanceof CompileException) { doStackTrace = false; isCompileException = true; if (compileException == null) // ! isLineCompileException) compileException = rootExn; } else if (rootExn instanceof LineException) { if (lineMessage == null) lineMessage = rootExn.getMessage(); } if (rootExn instanceof BadRequestException) { isBadRequest = true; } if (rootExn instanceof OutOfMemoryError) { String msg = "TcpSocketLink OutOfMemory"; ShutdownSystem.shutdownOutOfMemory(msg); } if (location != null || !lookupErrorPage) { } else if (rootExn instanceof LineMapException && rootExn instanceof ServletException && !(rootExn instanceof LineCompileException) && rootExn.getCause() != null) { // hack to deal with JSP wrapping } else if (!isServletException) { // SRV.9.9.2 Servlet 2.4 // location = getErrorPage(rootExn, ServletException.class); location = getErrorPage(rootExn); isServletException = true; } else { location = getErrorPage(rootExn); lookupErrorPage = false; } if (location != null) lookupErrorPage = false; if (isBadRequest) break; Throwable cause = null; if (rootExn instanceof ServletException && !(rootExn instanceof LineCompileException)) cause = ((ServletException) rootExn).getRootCause(); else { lookupErrorPage = false; cause = rootExn.getCause(); } if (cause != null) rootExn = cause; else { break; } } if (location == null && lookupErrorPage) { location = getErrorPage(rootExn); } if (location == null) location = getErrorPage(500); if (isBadRequest) { // server/05a0, server/0532 if (rootExn instanceof CompileException) title = rootExn.getMessage(); else title = String.valueOf(rootExn); doStackTrace = false; isBadRequest = true; if (request instanceof CauchoRequest) ((CauchoRequest) request).killKeepalive("bad request: " + rootExn); response.resetBuffer(); response.setStatus(HttpServletResponse.SC_BAD_REQUEST); /* * if (location == null) log.warn(e.toString()); */ } else if (rootExn instanceof UnavailableException) { UnavailableException unAvail = (UnavailableException) rootExn; if (unAvail.isPermanent()) { response.setStatus(HttpServletResponse.SC_NOT_FOUND); title = "404 Not Found"; if (location == null) location = getErrorPage(HttpServletResponse.SC_NOT_FOUND); } else { response.setStatus(HttpServletResponse.SC_SERVICE_UNAVAILABLE); title = "503 Unavailable"; if (unAvail.getUnavailableSeconds() > 0) response.setIntHeader("Retry-After", unAvail.getUnavailableSeconds()); if (location == null) location = getErrorPage(HttpServletResponse.SC_SERVICE_UNAVAILABLE); } } else { response.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR); } if (location == null) location = _defaultLocation; if (log.isTraceEnabled()) log.trace(e.toString(), e); else if (isCompileException) { if (isBadRequest) log.trace(BadRequestException.class.getSimpleName() + ": " + compileException.getMessage()); else log.trace(compileException.getMessage()); } else if (!doStackTrace) log.trace(rootExn.toString()); else log.trace(e.toString(), e); if (location != null) { if (errorPageExn == null) errorPageExn = rootExn; request.setAttribute(JSP_EXCEPTION, errorPageExn); request.setAttribute(RequestDispatcher.ERROR_EXCEPTION, errorPageExn); request.setAttribute(RequestDispatcher.ERROR_EXCEPTION_TYPE, errorPageExn.getClass()); if (request instanceof HttpServletRequest) request.setAttribute(RequestDispatcher.ERROR_REQUEST_URI, ((HttpServletRequest) request).getRequestURI()); String servletName = getServletName(request); if (servletName != null) request.setAttribute(RequestDispatcher.ERROR_SERVLET_NAME, servletName); request.setAttribute(RequestDispatcher.ERROR_STATUS_CODE, new Integer(500)); request.setAttribute(RequestDispatcher.ERROR_MESSAGE, errorPageExn.getMessage()); try { RequestDispatcher disp = null; // can't use filters because of error pages due to filters // or security. WebApp webApp = getWebApp(); if (webApp != null) disp = webApp.getRequestDispatcher(location); else if (_host != null) disp = _host.getWebAppContainer().getRequestDispatcher(location); if (disp != null) { ((RequestDispatcherImpl) disp).error(request, response); return; } } catch (Throwable e1) { log.info(e1.toString(), e1); rootExn = e1; } } response.setContentType("text/html"); String encoding = CharacterEncoding.getLocalEncoding(); if (encoding != null) response.setCharacterEncoding(encoding); else { Locale locale = Locale.getDefault(); if (!"ISO-8859-1".equals(Encoding.getMimeName(locale))) response.setLocale(Locale.getDefault()); else response.setCharacterEncoding("utf-8"); } PrintWriter out; try { out = response.getWriter(); } catch (IllegalStateException e1) { log.trace(e1.toString(), e1); out = new PrintWriter(new OutputStreamWriter(response.getOutputStream())); } if (isDevelopmentModeErrorPage()) { out.println("<html>"); if (!response.isCommitted()) out.println("<head><title>" + escapeHtml(title) + "</title></head>"); out.println("<body>"); out.println("<h1>" + escapeHtml(title) + "</h1>"); out.println("<code><pre>"); if (debug && !CurrentTime.isTest()) doStackTrace = true; if (doStackTrace) { out.println("<script language='javascript' type='text/javascript'>"); out.println("function show() { document.getElementById('trace').style.display = ''; }"); out.println("</script>"); out.print("<a style=\"text-decoration\" href=\"javascript:show();\">[show]</a> "); } if (compileException instanceof DisplayableException) { // ioc/0000 // XXX: dispExn.print doesn't normalize user.name // dispExn.print(out); out.println(escapeHtml(compileException.getMessage())); } else if (compileException != null) out.println(escapeHtml(compileException.getMessage())); else out.println(escapeHtml(rootExn.toString())); if (doStackTrace) { out.println("<span id=\"trace\" style=\"display:none\">"); printStackTrace(out, lineMessage, e, rootExn, lineMap); out.println("</span>"); } /* * if (doStackTrace || debug) { printStackTrace(out, lineMessage, e, rootExn, lineMap); } */ out.println("</pre></code>"); printVersion(out); out.println("</body></html>"); } else { // non-development mode out.println("<html>"); out.println("<title>Server Error</title>"); out.println("<body>"); out.println("<h1>Server Error</h1>"); out.println("<p>The server is temporarily unavailable due to an"); out.println("internal error. Please notify the system administrator"); out.println("of this problem.</p>"); out.println("<pre><code>"); out.println("Date: " + QDate.formatISO8601(CurrentTime.getCurrentTime())); out.println("</code></pre>"); printVersion(out); out.println("</body></html>"); } String userAgent = request.getHeader("User-Agent"); if (userAgent != null && userAgent.indexOf("MSIE") >= 0) { out.print(MSIE_PADDING); } out.close(); } private void printVersion(PrintWriter out) throws IOException { String version = null; version = VersionFactory.getFullVersion(); if (version != null) { out.println("<p /><hr />"); out.println("<small>"); out.println(version); out.println("</small>"); } } private String getServletName(ServletRequest request) { if (request instanceof HttpServletRequestImpl) return ((HttpServletRequestImpl) request).getServletName(); else if (request instanceof ServletRequestWrapper) return getServletName(((ServletRequestWrapper) request).getRequest()); else { return null; } } /** * Sends an HTTP error to the browser. * * @param code * the HTTP error code * @param message * a string message */ public void sendError(CauchoRequest request, CauchoResponse response, int code, String message) throws IOException { try { sendErrorImpl(request, response, code, message); } finally { response.close(); } } /** * Sends an HTTP error to the browser. * * @param code * the HTTP error code * @param message * a string message */ public void sendErrorImpl(CauchoRequest request, CauchoResponse response, int code, String message) throws IOException { response.resetBuffer(); /* XXX: if we've already got an error, won't this just mask it? if (responseStream.isCommitted()) throw new IllegalStateException("response can't sendError() after commit"); */ response.setStatus(code, message); try { if (handleErrorStatus(request, response, code, message) || code == HttpServletResponse.SC_NOT_MODIFIED) { return; } response.setContentType("text/html; charset=utf-8"); boolean isOutputStreamWrapper = false; PrintWriter out; try { out = response.getWriter(); } catch (IllegalStateException e) { log.debug(e.toString(), e); out = Vfs.openWrite(response.getOutputStream()).getPrintWriter(); isOutputStreamWrapper = true; } out.println("<html>"); if (!response.isCommitted()) { out.print("<head><title>"); out.print(code); out.print(" "); out.print(escapeHtml(message)); out.println("</title></head>"); } out.println("<body>"); out.print("<h1>"); out.print(code); out.print(" "); out.print(escapeHtml(message)); out.println("</h1>"); if (code == HttpServletResponse.SC_NOT_FOUND) { out.println(escapeHtml(request.getPageURI()) + " was not found on this server."); } printVersion(out); out.println("</body></html>"); String userAgent = request.getHeader("User-Agent"); if (userAgent != null && userAgent.indexOf("MSIE") >= 0) { out.write(MSIE_PADDING, 0, MSIE_PADDING.length); } if (isOutputStreamWrapper) { out.flush(); out.close(); } } catch (Exception e) { log.warn(e.toString(), e); } } /** * Handles an error status code. * * @return true if we've forwarded to an error page. */ private boolean handleErrorStatus(CauchoRequest request, CauchoResponse response, int code, String message) throws ServletException, IOException { if (code == HttpServletResponse.SC_OK || code == HttpServletResponse.SC_MOVED_TEMPORARILY || code == HttpServletResponse.SC_NOT_MODIFIED) return false; if (request.getRequestDepth(0) > 16) return false; else if (request.getAttribute(RequestDispatcher.ERROR_REQUEST_URI) != null) { return false; } response.killCache(); String location = getErrorPage(code); if (location == null) location = _defaultLocation; WebApp webApp = getWebApp(); if (webApp == null && _host == null) return false; if (location != null && !location.equals(request.getRequestURI())) { request.setAttribute(RequestDispatcher.ERROR_STATUS_CODE, new Integer(code)); request.setAttribute(RequestDispatcher.ERROR_MESSAGE, message); request.setAttribute(RequestDispatcher.ERROR_REQUEST_URI, request.getRequestURI()); String servletName = getServletName(request); if (servletName != null) request.setAttribute(RequestDispatcher.ERROR_SERVLET_NAME, servletName); try { RequestDispatcher disp = null; // can't use filters because of error pages due to filters // or security. if (webApp != null) disp = webApp.getRequestDispatcher(location); else if (_host != null) disp = _host.getWebAppContainer().getRequestDispatcher(location); // disp.forward(request, this, "GET", false); if (disp != null) { ((RequestDispatcherImpl) disp).error(request, response); } else return false; } catch (Throwable e) { sendServletError(e, request, response); } return true; } return false; } /** * Returns the URL of an error page for the given exception. */ String getErrorPage(Throwable e) { return getErrorPage(e, Throwable.class); } /** * Returns the URL of an error page for the given exception. */ String getErrorPage(Throwable e, Class<?> limit) { Class<?> cl = e.getClass(); for (; cl != null; cl = cl.getSuperclass()) { String location = (String) _errorPageMap.get(cl.getName()); if (location != null) return location; if (cl == limit) break; } for (cl = e.getClass(); cl != null; cl = cl.getSuperclass()) { String name = cl.getName(); int p = name.lastIndexOf('.'); if (p > 0) { name = name.substring(p + 1); String location = (String) _errorPageMap.get(name); if (location != null) return location; } if (cl == limit) break; } return null; } private WebApp getWebApp() { return _webApp; } /** * Returns the URL of an error page for the given exception. */ String getErrorPage(int code) { Integer key = new Integer(code); String location = (String) _errorPageMap.get(key); if (location != null) return location; return (String) _errorPageMap.get(new Integer(0)); } /** * Escapes HTML symbols in a stack trace. */ private void printStackTrace(PrintWriter out, String lineMessage, Throwable e, Throwable rootExn, LineMap lineMap) { CharArrayWriter writer = new CharArrayWriter(); PrintWriter pw = new PrintWriter(writer); if (lineMessage != null) pw.println(lineMessage); if (lineMap != null) lineMap.printStackTrace(e, pw); else ScriptStackTrace.printStackTrace(e, pw); pw.close(); char[] array = writer.toCharArray(); out.print(escapeHtml(new String(array))); } /** * Escapes special symbols in a string. For example '<' becomes '<' */ private String escapeHtml(String s) { if (s == null) return null; if (CurrentTime.isTest()) { s = normalizeForTesting(s); } CharBuffer cb = new CharBuffer(); int lineCharacter = 0; boolean startsWithSpace = false; for (int i = 0; i < s.length(); i++) { char ch = s.charAt(i); lineCharacter++; if (ch == '<') cb.append("<"); else if (ch == '&') cb.append("&"); /* * else if (ch == '%') cb.append("%25"); */ else if (ch == '\n' || ch == '\r') { lineCharacter = 0; cb.append(ch); startsWithSpace = false; } else if (lineCharacter > 70 && ch == ' ' && !startsWithSpace) { lineCharacter = 0; cb.append('\n'); for (; i + 1 < s.length() && s.charAt(i + 1) == ' '; i++) { } } else if (lineCharacter == 1 && (ch == ' ' || ch == '\t')) { cb.append((char) ch); startsWithSpace = true; } else cb.append(ch); } return cb.toString(); } private String normalizeForTesting(String s) { String userName = System.getProperty("user.name"); if ("caucho".equals(userName)) return s; int p; while ((p = s.indexOf(userName)) >= 0) { String head = s.substring(0, p); String tail = s.substring(p + userName.length()); s = head + "caucho" + tail; } return s; } public String toString() { return getClass().getSimpleName() + "[" + _webApp + "]"; } static { MSIE_PADDING = ("\n\n\n\n" + "<!--\n" + " - Because some older browsers replace their own messages\n" + " - to replace server error messages if the server\n" + " - message is too short, it's necessary to pad out\n" + " - the error message to be at least 512 bytes. With\n" + " - this padding, Resin more informative error messages\n" + " - are available, making debugging more straightforward.\n" + " - \n" + " - \n" + " - Padding message repeats:\n" + " - \n" + " - \n" + " - Because some older browsers replace their own messages\n" + " - to replace server error messages if the server\n" + " - message is too short, it's necessary to pad out\n" + " - the error message to be at least 512 bytes. With\n" + " - this padding, Resin more informative error messages\n" + " - are available, making debugging more straightforward.\n" + " - \n" + " -->\n") .toCharArray(); } }