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copied!<p>An update.</p> <p>My form sends a multipart request (needed since file upload is enabled on the form). I decided to log the post-data that comes to the server. I modified RequestDumperFilter.java to log the multipart post data. After i added this filter, the parameter loss issue seems to have ceased (0 loss out of 150 submissions of form). I removed the filter and was able to reproduce the issue again.</p> <p>Thanks, Raghuram </p> <pre><code>/* * 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 filters; import java.io.BufferedReader; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.PrintWriter; import java.io.StringWriter; import java.sql.Timestamp; import java.util.Enumeration; import java.util.Locale; import javax.servlet.Filter; import javax.servlet.FilterChain; import javax.servlet.FilterConfig; import javax.servlet.ServletException; import javax.servlet.ServletInputStream; import javax.servlet.ServletRequest; import javax.servlet.ServletResponse; import javax.servlet.http.Cookie; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletRequestWrapper; import javax.xml.ws.RequestWrapper; import com.oreilly.servlet.multipart.BufferedServletInputStream; /** * Example filter that dumps interesting state information about a request * to the associated servlet context log file, before allowing the servlet * to process the request in the usual way. This can be installed as needed * to assist in debugging problems. * * @author Craig McClanahan * @version $Revision: 500674 $ $Date: 2007-01-28 00:15:00 +0100 (dim., 28 janv. 2007) $ */ public final class RequestDumperFilter implements Filter { // ----------------------------------------------------- Instance Variables /** * The filter configuration object we are associated with. If this value * is null, this filter instance is not currently configured. */ private FilterConfig filterConfig = null; // --------------------------------------------------------- Public Methods /** * Take this filter out of service. */ public void destroy() { this.filterConfig = null; } /** * Time the processing that is performed by all subsequent filters in the * current filter stack, including the ultimately invoked servlet. * * @param request The servlet request we are processing * @param result The servlet response we are creating * @param chain The filter chain we are processing * * @exception IOException if an input/output error occurs * @exception ServletException if a servlet error occurs */ public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { if (filterConfig == null) return; // Render the generic servlet request properties StringWriter sw = new StringWriter(); PrintWriter writer = new PrintWriter(sw); writer.println("Request Received at " + (new Timestamp(System.currentTimeMillis()))); writer.println(" characterEncoding=" + request.getCharacterEncoding()); writer.println(" contentLength=" + request.getContentLength()); writer.println(" contentType=" + request.getContentType()); writer.println(" locale=" + request.getLocale()); writer.print(" locales="); Enumeration locales = request.getLocales(); boolean first = true; while (locales.hasMoreElements()) { Locale locale = (Locale) locales.nextElement(); if (first) first = false; else writer.print(", "); writer.print(locale.toString()); } writer.println(); Enumeration names = request.getParameterNames(); while (names.hasMoreElements()) { String name = (String) names.nextElement(); writer.print(" parameter=" + name + "="); String values[] = request.getParameterValues(name); for (int i = 0; i < values.length; i++) { if (i > 0) writer.print(", "); writer.print(values[i]); } writer.println(); } writer.println(" protocol=" + request.getProtocol()); writer.println(" remoteAddr=" + request.getRemoteAddr()); writer.println(" remoteHost=" + request.getRemoteHost()); writer.println(" scheme=" + request.getScheme()); writer.println(" serverName=" + request.getServerName()); writer.println(" serverPort=" + request.getServerPort()); writer.println(" isSecure=" + request.isSecure()); // Render the HTTP servlet request properties if (request instanceof HttpServletRequest) { writer.println("---------------------------------------------"); HttpServletRequest hrequest = (HttpServletRequest) request; writer.println(" contextPath=" + hrequest.getContextPath()); Cookie cookies[] = hrequest.getCookies(); if (cookies == null) cookies = new Cookie[0]; for (int i = 0; i < cookies.length; i++) { writer.println(" cookie=" + cookies[i].getName() + "=" + cookies[i].getValue()); } names = hrequest.getHeaderNames(); while (names.hasMoreElements()) { String name = (String) names.nextElement(); String value = hrequest.getHeader(name); writer.println(" header=" + name + "=" + value); } writer.println(" method=" + hrequest.getMethod()); writer.println(" pathInfo=" + hrequest.getPathInfo()); writer.println(" queryString=" + hrequest.getQueryString()); writer.println(" remoteUser=" + hrequest.getRemoteUser()); writer.println("requestedSessionId=" + hrequest.getRequestedSessionId()); writer.println(" requestURI=" + hrequest.getRequestURI()); writer.println(" servletPath=" + hrequest.getServletPath()); /* The following section is added by me to print the post data of a multipart request. */ writer.println("============================================="); writer.println("POST-DATA:"); writer.println("----------"); String line; BufferedRequestWrapper bufferedRequest= new BufferedRequestWrapper(hrequest); //Here obtain InputStream to process POST data! InputStream is = bufferedRequest.getInputStream(); BufferedReader br = new BufferedReader(new InputStreamReader(is)); while((line = br.readLine()) != null){ writer.println(line); } writer.println("============================================="); // Log the resulting string writer.flush(); filterConfig.getServletContext().log(sw.getBuffer().toString()); // Pass control on to the next filter chain.doFilter(bufferedRequest, response); } else { writer.println("============================================="); // Log the resulting string writer.flush(); filterConfig.getServletContext().log(sw.getBuffer().toString()); // Pass control on to the next filter chain.doFilter(request, response); } } /** * Place this filter into service. * * @param filterConfig The filter configuration object */ public void init(FilterConfig filterConfig) throws ServletException { this.filterConfig = filterConfig; } /** * Return a String representation of this object. */ public String toString() { if (filterConfig == null) return ("RequestDumperFilter()"); StringBuffer sb = new StringBuffer("RequestDumperFilter("); sb.append(filterConfig); sb.append(")"); return (sb.toString()); } public class BufferedRequestWrapper extends HttpServletRequestWrapper { ByteArrayInputStream bais; ByteArrayOutputStream baos; BufferedServletInputStream bsis; byte [] buffer; public BufferedRequestWrapper(HttpServletRequest req) throws IOException { super(req); // Read InputStream and store its content in a buffer. InputStream is = req.getInputStream(); baos = new ByteArrayOutputStream(); byte buf[] = new byte[1024]; int letti; while ((letti=is.read(buf))>0) baos.write(buf,0,letti); buffer = baos.toByteArray(); } public ServletInputStream getInputStream() { try { // Generate a new InputStream by stored buffer bais = new ByteArrayInputStream(buffer); // Istantiate a subclass of ServletInputStream // (Only ServletInputStream or subclasses of it are accepted by the servlet engine!) bsis = new BufferedServletInputStream(bais); } catch (Exception ex) { ex.printStackTrace(); } finally { return bsis; } } } /* Subclass of ServletInputStream needed by the servlet engine. All inputStream methods are wrapped and are delegated to the ByteArrayInputStream (obtained as constructor parameter)! */ public class BufferedServletInputStream extends ServletInputStream { ByteArrayInputStream bais; public BufferedServletInputStream(ByteArrayInputStream bais) { this.bais = bais; } public int available() { return bais.available(); } public int read() { return bais.read(); } public int read(byte[] buf,int off,int len) { return bais.read(buf,off,len); } } } </code></pre>

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