/**
 * Copyright (C) 2011  JTalks.org Team
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * This library 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
 * Lesser General Public License for more details.
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */
package org.jtalks.jcommune.web.filters;

import org.jtalks.jcommune.web.filters.wrapper.ForceGetRequestWrapper;
import org.jtalks.jcommune.web.filters.wrapper.NoBodyResponseWrapper;

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * Filter for process head http request.
 * Catch it and set GET request the default type and send empty response body according to HTTP standard
 */
public class HeadRequestTypeFilter implements Filter {

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        HttpServletResponse httpServletResponse = (HttpServletResponse) response;

        if (isHeadTypeRequest(httpServletRequest)) {

            NoBodyResponseWrapper noBodyResponseWrapper = new NoBodyResponseWrapper(httpServletResponse);

            chain.doFilter(new ForceGetRequestWrapper(httpServletRequest), noBodyResponseWrapper);
            noBodyResponseWrapper.setContentLength();

        } else {
            chain.doFilter(request, response);
        }
    }

    private boolean isHeadTypeRequest(HttpServletRequest request) {
        return "HEAD".equals(request.getMethod());
    }

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

    @Override
    public void destroy() {
    }
}