DispatchServlet.java

// ========================================================================
// Copyright (c) 1996-2009 Mort Bay Consulting Pty. Ltd.
// ------------------------------------------------------------------------
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// and Apache License v2.0 which accompanies this distribution.
// The Eclipse Public License is available at 
// http://www.eclipse.org/legal/epl-v10.html
// The Apache License v2.0 is available at
// http://www.opensource.org/licenses/apache2.0.php
// You may elect to redistribute this code under either of these licenses. 
// ========================================================================

package com.acme;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletResponseWrapper;

import org.eclipse.jetty.util.log.Log;
import org.eclipse.jetty.util.log.Logger;


/* ------------------------------------------------------------ */
/** Test Servlet RequestDispatcher.
 * 
 * 
 */
public class DispatchServlet extends HttpServlet
{
    private static final Logger LOG = Log.getLogger(DispatchServlet.class);

    /* ------------------------------------------------------------ */
    String pageType;

    /* ------------------------------------------------------------ */
    @Override
    public void doPost(HttpServletRequest sreq, HttpServletResponse sres) throws ServletException, IOException
    {
        doGet(sreq, sres);
    }

    /* ------------------------------------------------------------ */
    @Override
    public void doGet(HttpServletRequest sreq, HttpServletResponse sres) throws ServletException, IOException
    {
        if (sreq.getParameter("wrap") != null)
        {
            sreq= new HttpServletRequestWrapper(sreq);
            sres= new HttpServletResponseWrapper(sres);
        }
        
        if (sreq.getParameter("session") != null)
            sreq.getSession(true);

        String prefix=
            sreq.getContextPath() != null ? sreq.getContextPath() + sreq.getServletPath() : sreq.getServletPath();
            
        String info;
        
        if (sreq.getAttribute("javax.servlet.include.servlet_path") != null)
            info= (String)sreq.getAttribute("javax.servlet.include.path_info");
        else
            info= sreq.getPathInfo();
        
        if (info == null)
            info= "NULL";

        if (info.indexOf(sreq.getServletPath()) > 0)
        {
            sres.sendError(403,"Nested " + sreq.getServletPath() + " forbidden.");
            return;
        }
        
        if(info.indexOf(getServletName()) > 0)
        {
            sres.sendError(403,"Nested " + getServletName() + " forbidden.");
            return;
        }

        if (info.startsWith("/includeW/"))
        {
            sres.setContentType("text/html");
            info= info.substring(9);
            if (info.indexOf('?') < 0)
                info += "?Dispatch=include";
            else
                info += "&Dispatch=include";
            
            PrintWriter pout= null;
            pout= sres.getWriter();
            pout.write("<H1>Include (writer): " + info + "</H1><HR>");
            
            RequestDispatcher dispatch= getServletContext().getRequestDispatcher(info);
            if (dispatch == null)
            {
                pout= sres.getWriter();
                pout.write("<H1>Null dispatcher</H1>");
            }
            else
                dispatch.include(sreq, sres);
            
            pout.write("<HR><H1>-- Included (writer)</H1>");
        }
        else if (info.startsWith("/includeS/"))
        {
            sres.setContentType("text/html");
            info= info.substring(9);
            if (info.indexOf('?') < 0)
                info += "?Dispatch=include";
            else
                info += "&Dispatch=include";
            
            OutputStream out= null;
            out= sres.getOutputStream();
            out.write(("<H1>Include (outputstream): " + info + "</H1><HR>").getBytes());
            
            RequestDispatcher dispatch= getServletContext().getRequestDispatcher(info);
            if (dispatch == null)
            {
                out= sres.getOutputStream();
                out.write("<H1>Null dispatcher</H1>".getBytes());
            }
            else
                dispatch.include(sreq, sres);
            
            out.write("<HR><H1>-- Included (outputstream)</H1>".getBytes());
            
        }
        else if (info.startsWith("/forward/"))
        {
            info= info.substring(8);
            if (info.indexOf('?') < 0)
                info += "?Dispatch=forward";
            else
                info += "&Dispatch=forward";
            
            RequestDispatcher dispatch= getServletContext().getRequestDispatcher(info);
            if (dispatch != null)
            {
                ServletOutputStream out =sres.getOutputStream();
                out.print("Can't see this");
                dispatch.forward(sreq, sres);
                try
                {
                    // should be closed
                    out.println("IOException");
                    // should not get here
                    throw new IllegalStateException();
                }
                catch(IOException e)
                {
                    LOG.ignore(e);
                }
            }
            else
            {
                sres.setContentType("text/html");
                PrintWriter pout= sres.getWriter();
                pout.write("<H1>No dispatcher for: " + info + "</H1><HR>");
                pout.flush();
            }
        }
        else if (info.startsWith("/forwardC/"))
        {
            info= info.substring(9);
            if (info.indexOf('?') < 0)
                info += "?Dispatch=forward";
            else
                info += "&Dispatch=forward";
            
            String cpath= info.substring(0, info.indexOf('/', 1));
            info= info.substring(cpath.length());
            
            ServletContext context= getServletContext().getContext(cpath);
            RequestDispatcher dispatch= context.getRequestDispatcher(info);
            
            if (dispatch != null)
            {
                dispatch.forward(sreq, sres);
            }
            else
            {
                sres.setContentType("text/html");
                PrintWriter pout= sres.getWriter();
                pout.write("<H1>No dispatcher for: " + cpath + "/" + info + "</H1><HR>");
                pout.flush();
            }
        }
        else if (info.startsWith("/includeN/"))
        {
            sres.setContentType("text/html");
            info= info.substring(10);
            if (info.indexOf("/") >= 0)
                info= info.substring(0, info.indexOf("/"));
            
            PrintWriter pout;
            if (info.startsWith("/null"))
                info= info.substring(5);
            else
            {
                pout= sres.getWriter();
                pout.write("<H1>Include named: " + info + "</H1><HR>");
            }
            
            RequestDispatcher dispatch= getServletContext().getNamedDispatcher(info);
            if (dispatch != null)
                dispatch.include(sreq, sres);
            else
            {
                pout= sres.getWriter();
                pout.write("<H1>No servlet named: " + info + "</H1>");
            }
            
            pout= sres.getWriter();
            pout.write("<HR><H1>Included ");
        }
        else if (info.startsWith("/forwardN/"))
        {
            info= info.substring(10);
            if (info.indexOf("/") >= 0)
                info= info.substring(0, info.indexOf("/"));
            RequestDispatcher dispatch= getServletContext().getNamedDispatcher(info);
            if (dispatch != null)
                dispatch.forward(sreq, sres);
            else
            {
                sres.setContentType("text/html");
                PrintWriter pout= sres.getWriter();
                pout.write("<H1>No servlet named: " + info + "</H1>");
                pout.flush();
            }
        }
        else
        {
            sres.setContentType("text/html");
            PrintWriter pout= sres.getWriter();
            pout.write(
                    "<H1>Dispatch URL must be of the form: </H1>"
                    + "<PRE>"
                    + prefix
                    + "/includeW/path\n"
                    + prefix
                    + "/includeS/path\n"
                    + prefix
                    + "/forward/path\n"
                    + prefix
                    + "/includeN/name\n"
                    + prefix
                    + "/forwardC/_context/path\n</PRE>");
        }
        
    }

    /* ------------------------------------------------------------ */
    @Override
    public String getServletInfo()
    {
        return "Include Servlet";
    }

    /* ------------------------------------------------------------ */
    @Override
    public synchronized void destroy()
    {
    }

}