de.blizzy.documentr.web.filter.TrimFilter.java Source code

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Here is the source code for de.blizzy.documentr.web.filter.TrimFilter.java

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/*
documentr - Edit, maintain, and present software documentation on the web.
Copyright (C) 2012-2013 Maik Schreiber
    
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.blizzy.documentr.web.filter;

import java.io.BufferedReader;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.StringReader;
import java.nio.charset.Charset;

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.HttpServletResponse;

import com.google.common.io.Closeables;

public class TrimFilter implements Filter {
    private TrimWriter writer = new TrimWriter();

    @Override
    public void init(FilterConfig filterConfig) {
    }

    @Override
    public void destroy() {
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {

        HttpServletResponse resp = (HttpServletResponse) response;
        TrimResponseWrapper trimResponse = new TrimResponseWrapper(resp);
        chain.doFilter(request, trimResponse);

        Boolean trimmable = trimResponse.isTrimmable();
        if ((trimmable != null) && trimmable.booleanValue()) {
            byte[] data = getTrimmedData(trimResponse);
            response.setContentLength(data.length);
            response.getOutputStream().write(data);
        }
    }

    private byte[] getTrimmedData(TrimResponseWrapper trimResponse) throws IOException {
        BufferedReader in = null;
        ByteArrayOutputStream out = null;
        try {
            Charset charset = Charset.forName(trimResponse.getCharacterEncoding());
            String text = new String(trimResponse.getData(), charset);
            in = new BufferedReader(new StringReader(text));
            out = new ByteArrayOutputStream();
            writer.write(text, out, charset);
        } finally {
            Closeables.closeQuietly(in);
            Closeables.closeQuietly(out);
        }
        return out.toByteArray();
    }
}