RequestDumperFilter.java

/*
* 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 filter;


import java.io.IOException;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.sql.Timestamp;
import java.util.Enumeration;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;


/**
 * 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: 1.1 $ $Date: 2010/07/09 08:18:13 $
 */

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();
	Enumeration names = request.getParameterNames();
	writer.println( "----------------parameters-----------" );
	while (names.hasMoreElements()) {
	    String name = (String) names.nextElement();
	    writer.print("         " + 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());
	    
//	    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());
	}
	writer.println("=============================================");
	System.out.println( sw.getBuffer().toString() );
	// 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());

    }


}