PerFrameDeflateEncoder Class — netty Architecture

Source Code

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/extensions/compression/PerFrameDeflateEncoder.java lines 28–81

class PerFrameDeflateEncoder extends DeflateEncoder {

    /**
     * Constructor
     *
     * @param compressionLevel compression level of the compressor.
     * @param windowSize       maximum size of the window compressor buffer.
     * @param noContext        true to disable context takeover.
     */
    PerFrameDeflateEncoder(int compressionLevel, int windowSize, boolean noContext) {
        super(compressionLevel, windowSize, noContext, WebSocketExtensionFilter.NEVER_SKIP);
    }

    /**
     * Constructor
     *
     * @param compressionLevel compression level of the compressor.
     * @param windowSize       maximum size of the window compressor buffer.
     * @param noContext        true to disable context takeover.
     * @param extensionEncoderFilter extension encoder filter for per frame deflate encoder.
     */
    PerFrameDeflateEncoder(int compressionLevel, int windowSize, boolean noContext,
                           WebSocketExtensionFilter extensionEncoderFilter) {
        super(compressionLevel, windowSize, noContext, extensionEncoderFilter);
    }

    @Override
    public boolean acceptOutboundMessage(Object msg) throws Exception {
        if (!super.acceptOutboundMessage(msg)) {
            return false;
        }

        WebSocketFrame wsFrame = (WebSocketFrame) msg;
        if (extensionEncoderFilter().mustSkip(wsFrame)) {
            return false;
        }

        return (msg instanceof TextWebSocketFrame || msg instanceof BinaryWebSocketFrame ||
                msg instanceof ContinuationWebSocketFrame) &&
               wsFrame.content().readableBytes() > 0 &&
               (wsFrame.rsv() & WebSocketExtension.RSV1) == 0;
    }

    @Override
    protected int rsv(WebSocketFrame msg) {
        return msg.rsv() | WebSocketExtension.RSV1;
    }

    @Override
    protected boolean removeFrameTail(WebSocketFrame msg) {
        return true;
    }

}