/*
 * JBoss, the OpenSource J2EE webOS
 *
 * Distributable under LGPL license.
 * See terms of license at gnu.org.
 */

package org.jboss.net.axis.server;

import org.jboss.axis.transport.http.HTTPConstants;
import org.jboss.logging.Logger;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * A AxisServlet that allows the Flash player/plugin to interact with the
 * Axis SOAP engine despite the inability to generate the SOAPAction HTTP
 * header.  It spoofs the header by looking at the request parameters and
 * generating a derived HttpServletRequestWrapper class to appear to migrate
 * those that should actually be HTTP headers into the header.  This class
 * then just calls its base class's implementation of doPost().
 *
 * For example, if you were invoking the Hello World SOAP example, you would
 * append:
 *
 *    ?SOAPAction=\"Hello\"
 * 
 * to the service context:
 *
 *    /axisflash/flashservices/Hello
 *
 * <h3> Change History </h3>
 * <ul>
 * <li> jung, 02.05.2002: Outsourced the strings. </li>
 * </ul>
 * @author <a href="mailto:fbrier@multideck.com">Frederick N. Brier</a>
 * @created 22.04.2002
 * @version $Revision: 1.7.6.1 $
 */
public class FlashAxisServiceServlet extends AxisServiceServlet
{
   /**
    * This is a spoofing class whose sole purpose is to make it appear that
    * the HTTP "SOAPAction" parameter is actually an HTTP Header attribute.
    */
   public class FilteredHttpServletRequest extends HttpServletRequestWrapper
   {
      /** we keep the parameter here */
      protected String soapAction;

      /**
       * Constructs an instance with the soapAction set to the value of the
       * HTTP "SOAPAction" parameter.
       * @param req - HttpServletRequest that is getting spoofed
       * @exception IllegalArgumentException is thrown if either the request
       * already had a SOAPAction header or if there is no SOAPAction
       * parameter.
       */
      public FilteredHttpServletRequest(HttpServletRequest req)
              throws IllegalArgumentException
      {
         super(req);

         soapAction = (String)req.getHeader(HTTPConstants.HEADER_SOAP_ACTION);

         if (null != soapAction)
         {
            // SOAPAction provided.  Don't need spoofed request.
            log.error(Constants.ERR_EXISTING_HEADER);
            throw new IllegalArgumentException(Constants.ERR_EXISTING_HEADER);
         }

         soapAction = getParameter(HTTPConstants.HEADER_SOAP_ACTION);

         if (null == soapAction)
         {
            log.error(Constants.ERR_MISSING_PARM);
            throw new IllegalArgumentException(Constants.ERR_MISSING_PARM);
         }

         log.trace("FilteredHttpServletRequest.ctor(): Matched SOAPAction parameter");

      } // of FilteredHttpServletRequest constructor

      /**
       * If there is a SOAPAction HTTP parameter, return that value instead of NULL.
       * Otherwise, default to the base class behavior.
       * @param name - a String specifying the header name
       * @returns a String containing the value of the SOAPAction HTTP parameter if
       * that is what is requested via the name parameter, otherwise returns the
       * expected HTTP Header value, or null if the request does not have a header
       * of that name
       */

      public String getHeader(String name)
      {
         log.trace("FlashAxisServiceServlet.FilteredHttpServletRequest.getHeader()");
         if (name.equals(HTTPConstants.HEADER_SOAP_ACTION))
         {
            log.trace("getHeader(): Matched SOAPAction header request");
            return soapAction;
         }
         else
         {
            log.trace("getHeader(): Not a SOAPAction header request, called base class method.");
            return super.getHeader(name);
         }
      } // of method getHeader

   } // of class FilteredHttpServletRequest

   /**
    * The instance logger for the service.  Not using a class logger
    * because we want to dynamically obtain the logger name from
    * concrete sub-classes.
    */
   protected Logger log;

   /**
    * Creates new AxisServlet
    */
   public FlashAxisServiceServlet()
   {
      super();

      log = Logger.getLogger(getClass());
      log.trace("Constructing");
   }

   /**
    * This method sits on top of the AxisService.doPost() acting as a filter
    * by first creating a FilterHttpServletRequest and passing it to the base
    * class implementation.
    * @param req - an HttpServletRequest object that contains the request the
    * client has made of the servlet
    * @param resp - an HttpServletResponse object that contains the response
    * the servlet sends to the client
    * @exception IOException if an input or output error is detected when the
    * servlet handles the request
    * @exception ServletException   if the request for the POST could not be
    * handled
    */
   public void doPost(HttpServletRequest req, HttpServletResponse res)
           throws ServletException, IOException
   {
      HttpServletRequest newReq = req;
      try
      {
         newReq = new FilteredHttpServletRequest(req);
         log.trace("doPost(): Successfully created a FilteredHttpServletRequest object.");
      }
      catch (IllegalArgumentException e)
      {
         log.error("doPost(): Failed to create a FilteredHttpServletRequest object.  Use original HttpServletRequest.");
      }

      super.doPost(newReq, res);
   }

}