private ChannelFuture sendFile(ChannelHandlerContext ctx, Channel ch, FileChunk file) throws IOException { RandomAccessFile raf; try { raf = new RandomAccessFile(file.getFile(), "r"); } catch (FileNotFoundException fnfe) { return null; } ChannelFuture writeFuture; if (ch.getPipeline().get(SslHandler.class) != null) { // Cannot use zero-copy with HTTPS. writeFuture = ch.write(new ChunkedFile(raf, file.startOffset(), file.length(), 8192)); } else { // No encryption - use zero-copy. final FileRegion region = new DefaultFileRegion(raf.getChannel(), file.startOffset(), file.length()); writeFuture = ch.write(region); writeFuture.addListener( new ChannelFutureListener() { public void operationComplete(ChannelFuture future) { region.releaseExternalResources(); } }); } return writeFuture; }