CustomHttpContentCompressor.java 文件源码

@Override
protected void encode(ChannelHandlerContext ctx, HttpObject msg, List<Object> out)
    throws Exception {
  if (msg instanceof HttpResponse) {
    HttpResponse res = (HttpResponse) msg;

    skipCompression = false;

    // if an "content-encoding: identity" header was set, we do not compress
    if (skipCompression = res.headers().containsValue(
        HttpHeaderNames.CONTENT_ENCODING,
        HttpHeaderValues.IDENTITY,
        true)) {
      // remove header as one should not send Identity as content encoding
      res.headers().remove(HttpHeaderNames.CONTENT_ENCODING);
    } else {
      CharSequence mimeType = HttpUtil.getMimeType(res);
      // skip compression if the media type is not compressible by the server
      skipCompression = mimeType != null && !isCompressable(MediaType.parse(mimeType.toString()));

      // skip compression if the content length is less than expected by the server
      int contentLength = res.headers().getInt(HttpHeaderNames.CONTENT_LENGTH, 0);
      skipCompression = contentLength > 0 && contentLength < compressionContentLength;
    }
  }

  super.encode(ctx, msg, out);
}