/*
 *  Nutzerverwaltung - User and role management in your browser
 *  Copyright (C) 2011-2016 Ulrich Hilger, http://uhilger.de
 *
 *  This program 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 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see http://www.gnu.org/licenses/
 */

package de.uhilger.um.web;

import java.io.IOException;
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;

/**
 * Filter zum Verkuerzen von URLs
 *
 * @author Copyright (c) Ulrich Hilger, http://uhilger.de
 * @author Published under the terms and conditions of the
 * <a href="http://www.gnu.org/licenses/agpl-3.0" target="_blank">GNU Affero
 * General Public License</a>
 *
 * @version 2, February 1, 2017
 */
public class NiceFilter implements Filter {
  
  private static final String ZIEL = "../api?c=de.uhilger.um.api.UserMgr&m=";

  @Override
  public void init(FilterConfig filterConfig) throws ServletException {
    // ...
  }

  /*
    hier wird ein URL wie z.B. 
    http]://example.com/um/svc/testmethode
    umgesetzt auf
    http]://example.com/um/api?c=de.uhilger.um.api.UserMgr&m=testmethode
  
    der Teil 'svc' ist im Filter Mapping des Deployment Descriptor 
    deklariert. Der Teil 'api' zeigt mit Hilfe eines Servlet 
    Mappings im Deployment Descriptor auf das Transit-Servlet.
  
    der statische Teil des Ziel-URL ist hier hart kodiert, das kann man 
    freilich je nach Bedarf noch dynamisch gestalten
  */
  
  @Override
  public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
    if(request instanceof HttpServletRequest) {
      HttpServletRequest hr = (HttpServletRequest) request;
      String servletPath = hr.getServletPath();
      String[] path = servletPath.split("/");
      request.getRequestDispatcher(ZIEL + path[2]).forward(request, response);
    }
  }

  @Override
  public void destroy() {
    // ...
  }
  
}