package org.appfuse.webapp.filter;
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;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
public class GZIPFilter implements Filter {
private static Log log = LogFactory.getLog(GZIPFilter.class);
public void doFilter(ServletRequest req, ServletResponse res,
FilterChain chain)
throws IOException, ServletException {
if (req instanceof HttpServletRequest) {
HttpServletRequest request = (HttpServletRequest) req;
HttpServletResponse response = (HttpServletResponse) res;
if (isGZIPSupported(request)) {
if (log.isDebugEnabled()) {
log.debug("GZIP supported, compressing response");
}
GZIPResponseWrapper wrappedResponse =
new GZIPResponseWrapper(response);
chain.doFilter(req, wrappedResponse);
wrappedResponse.finishResponse();
return;
}
chain.doFilter(req, res);
}
}
private boolean isGZIPSupported(HttpServletRequest req) {
String browserEncodings = req.getHeader("accept-encoding");
boolean supported =
((browserEncodings != null) &&
(browserEncodings.indexOf("gzip") != -1));
String userAgent = req.getHeader("user-agent");
if (userAgent.startsWith("httpunit")) {
if (log.isDebugEnabled()) {
log.debug("httpunit detected, disabling filter...");
}
return false;
} else {
return supported;
}
}
public void init(FilterConfig filterConfig) {
}
public void destroy() {
}
}