wro4j-core/src/main/java/ro/isdc/wro/util/WroUtil.java
@SuppressWarnings("unchecked")
  public static boolean isGzipSupported(final HttpServletRequest request) {
    if (request != null) {
      final Enumeration<String> headerNames = request.getHeaderNames();
      if (headerNames != null) {
        while (headerNames.hasMoreElements()) {
          final String headerName = headerNames.nextElement();
          final Matcher m = PATTERN_ACCEPT_ENCODING.matcher(headerName);
          if (m.find()) {
            final String headerValue = request.getHeader(headerName);
            final Matcher mValue = PATTERN_GZIP.matcher(headerValue);
            return mValue.find();
          }
        }
      }
    }
    return false;
  }
@SuppressWarnings("unchecked")
  public static boolean isGzipSupported(final HttpServletRequest request) {
    if (request != null) {
      final Enumeration<String> headerNames = request.getHeaderNames();
      if (headerNames != null) {
        while (headerNames.hasMoreElements()) {
          final String headerName = headerNames.nextElement();
          final Matcher m = PATTERN_ACCEPT_ENCODING.matcher(headerName);
          if (m.find()) {
            final String headerValue = request.getHeader(headerName);
            final Matcher mValue = PATTERN_GZIP.matcher(headerValue);
            return mValue.find();
          }
        }
      }
    }
    return false;
  }
Analyze headers of the request and searches for mangled (by proxy) for "Accept-Encoding" header and its mangled
variations and gzip header value and its mangled variations.

@return true if this request support gzip encoding.