SpdySessionHandler Class — netty Architecture

Source Code

codec-http/src/main/java/io/netty/handler/codec/spdy/SpdySessionHandler.java lines 34–841

public class SpdySessionHandler extends ChannelDuplexHandler {

    private static final SpdyProtocolException PROTOCOL_EXCEPTION =
            SpdyProtocolException.newStatic(null, SpdySessionHandler.class, "handleOutboundMessage(...)");
    private static final SpdyProtocolException STREAM_CLOSED =
            SpdyProtocolException.newStatic("Stream closed", SpdySessionHandler.class, "removeStream(...)");

    private static final int DEFAULT_WINDOW_SIZE = 64 * 1024; // 64 KB default initial window size
    private int initialSendWindowSize    = DEFAULT_WINDOW_SIZE;
    private int initialReceiveWindowSize = DEFAULT_WINDOW_SIZE;
    private volatile int initialSessionReceiveWindowSize = DEFAULT_WINDOW_SIZE;

    private final SpdySession spdySession = new SpdySession(initialSendWindowSize, initialReceiveWindowSize);
    private int lastGoodStreamId;

    private static final int DEFAULT_MAX_CONCURRENT_STREAMS = Integer.MAX_VALUE;
    private int remoteConcurrentStreams = DEFAULT_MAX_CONCURRENT_STREAMS;
    private int localConcurrentStreams  = DEFAULT_MAX_CONCURRENT_STREAMS;

    private final AtomicInteger pings = new AtomicInteger();

    private boolean sentGoAwayFrame;
    private boolean receivedGoAwayFrame;

    private ChannelFutureListener closeSessionFutureListener;

    private final boolean server;
    private final int minorVersion;

    /**
     * Creates a new session handler.
     *
     * @param version the protocol version
     * @param server  {@code true} if and only if this session handler should
     *                handle the server endpoint of the connection.
     *                {@code false} if and only if this session handler should
     *                handle the client endpoint of the connection.
     */
    public SpdySessionHandler(SpdyVersion version, boolean server) {
        this.minorVersion = ObjectUtil.checkNotNull(version, "version").minorVersion();
        this.server = server;
    }

    public void setSessionReceiveWindowSize(int sessionReceiveWindowSize) {
        checkPositiveOrZero(sessionReceiveWindowSize, "sessionReceiveWindowSize");
        // This will not send a window update frame immediately.
        // If this value increases the allowed receive window size,
        // a WINDOW_UPDATE frame will be sent when only half of the
        // session window size remains during data frame processing.
        // If this value decreases the allowed receive window size,
        // the window will be reduced as data frames are processed.
        initialSessionReceiveWindowSize = sessionReceiveWindowSize;
    }

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        if (msg instanceof SpdyDataFrame) {

            /*
             * SPDY Data frame processing requirements:
             *
             * If an endpoint receives a data frame for a Stream-ID which is not open
             * and the endpoint has not sent a GOAWAY frame, it must issue a stream error
             * with the error code INVALID_STREAM for the Stream-ID.
             *
             * If an endpoint which created the stream receives a data frame before receiving
             * a SYN_REPLY on that stream, it is a protocol error, and the recipient must
             * issue a stream error with the getStatus code PROTOCOL_ERROR for the Stream-ID.
             *
             * If an endpoint receives multiple data frames for invalid Stream-IDs,
             * it may close the session.
             *
             * If an endpoint refuses a stream it must ignore any data frames for that stream.
             *
             * If an endpoint receives a data frame after the stream is half-closed from the
             * sender, it must send a RST_STREAM frame with the getStatus STREAM_ALREADY_CLOSED.
             *
             * If an endpoint receives a data frame after the stream is closed, it must send
             * a RST_STREAM frame with the getStatus PROTOCOL_ERROR.
             */
            SpdyDataFrame spdyDataFrame = (SpdyDataFrame) msg;