Class Http2Protocol

java/org/apache/coyote/http2/Http2Protocol.java:46–717

HTTP/2 protocol handler. Implements the UpgradeProtocol interface to allow HTTP/2 to be used as an upgrade from HTTP/1.1 or via ALPN.

 * from HTTP/1.1 or via ALPN.
 */
public class Http2Protocol implements UpgradeProtocol {

    /**
     * Creates a new instance of the HTTP/2 protocol handler.
     */
    public Http2Protocol() {
        super();
    }


    private static final Log log = LogFactory.getLog(Http2Protocol.class);
    private static final StringManager sm = StringManager.getManager(Http2Protocol.class);

    static final long DEFAULT_READ_TIMEOUT = 5000;
    static final long DEFAULT_WRITE_TIMEOUT = 5000;
    static final long DEFAULT_KEEP_ALIVE_TIMEOUT = 20000;
    static final long DEFAULT_STREAM_READ_TIMEOUT = 20000;
    static final long DEFAULT_STREAM_WRITE_TIMEOUT = 20000;
    // The HTTP/2 specification recommends a minimum default of 100
    static final long DEFAULT_MAX_CONCURRENT_STREAMS = 100;
    // Maximum amount of streams which can be concurrently executed over
    // a single connection
    static final int DEFAULT_MAX_CONCURRENT_STREAM_EXECUTION = 20;
    // Default factor used when adjusting overhead count for overhead frames
    static final int DEFAULT_OVERHEAD_COUNT_FACTOR = 10;
    // Default factor used when adjusting overhead count for reset frames
    static final int DEFAULT_OVERHEAD_RESET_FACTOR = 50;
    // Not currently configurable. This makes the practical limit for
    // overheadCountFactor to be ~20. The exact limit will vary with traffic
    // patterns.
    static final int DEFAULT_OVERHEAD_REDUCTION_FACTOR = -20;
    static final int DEFAULT_OVERHEAD_CONTINUATION_THRESHOLD = 1024;
    static final int DEFAULT_OVERHEAD_DATA_THRESHOLD = 1024;
    static final int DEFAULT_OVERHEAD_WINDOW_UPDATE_THRESHOLD = 1024;

    private static final String HTTP_UPGRADE_NAME = "h2c";
    private static final String ALPN_NAME = "h2";
    private static final byte[] ALPN_IDENTIFIER = ALPN_NAME.getBytes(StandardCharsets.UTF_8);

    // All timeouts in milliseconds
    // These are the socket level timeouts
    private long readTimeout = DEFAULT_READ_TIMEOUT;
    private long writeTimeout = DEFAULT_WRITE_TIMEOUT;
    private long keepAliveTimeout = DEFAULT_KEEP_ALIVE_TIMEOUT;
    // These are the stream level timeouts
    private long streamReadTimeout = DEFAULT_STREAM_READ_TIMEOUT;
    private long streamWriteTimeout = DEFAULT_STREAM_WRITE_TIMEOUT;

    private long maxConcurrentStreams = DEFAULT_MAX_CONCURRENT_STREAMS;
    private int maxConcurrentStreamExecution = DEFAULT_MAX_CONCURRENT_STREAM_EXECUTION;
    // To advertise a different default to the client specify it here but DO NOT
    // change the default defined in ConnectionSettingsBase.
    private int initialWindowSize = ConnectionSettingsBase.DEFAULT_INITIAL_WINDOW_SIZE;
    // Limits
    private int maxHeaderCount = Constants.DEFAULT_MAX_HEADER_COUNT;
    private int maxTrailerCount = Constants.DEFAULT_MAX_TRAILER_COUNT;
    private int overheadCountFactor = DEFAULT_OVERHEAD_COUNT_FACTOR;
    private int overheadResetFactor = DEFAULT_OVERHEAD_RESET_FACTOR;