Package io.grpc.servlet.web.websocket

Class MultiplexedWebSocketServerStream

java.lang.Object

jakarta.websocket.Endpoint

io.grpc.servlet.web.websocket.AbstractWebSocketServerStream

io.grpc.servlet.web.websocket.MultiplexedWebSocketServerStream

public class MultiplexedWebSocketServerStream
extends AbstractWebSocketServerStream

Each instance of this type represents a single active websocket, which can allow several concurrent/overlapping gRPC streams. This is in contrast to the WebSocketServerStream type, which supports one websocket per gRPC stream.

To achieve this, each grpc message starts with a 32 bit integer indicating the ID of the stream. If the MSB of that int is 1, then the request must be closed by this message, and that MSB is set to zero to read the ID of the stream. On the initial request, an extra header is sent from the client, indicating the path to the service method. Technically, this makes it possible for a grpc message to split across several websocket frames, but at this time each grpc message is exactly one websocket frame.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	MultiplexedWebSocketServerStream.GracefulClose	Callback to initiate a graceful shutdown of this websocket instance, as an alternative to just closing the websocket.

Field Summary

Fields

Modifier and Type	Field	Description
static final String	GRACEFUL_CLOSE
static final String	GRPC_WEBSOCKETS_MULTIPLEX_PROTOCOL
static final io.grpc.Metadata.Key<String>	PATH	Custom metadata to hold the path requested by the incoming stream

Fields inherited from class io.grpc.servlet.web.websocket.AbstractWebSocketServerStream

attributes, maxInboundMessageSize, streamTracerFactories, transportListener, websocketSession

Constructor Summary

Constructors

Constructor	Description
MultiplexedWebSocketServerStream(io.grpc.internal.ServerTransportListener transportListener, List<? extends io.grpc.ServerStreamTracer.Factory> streamTracerFactories, int maxInboundMessageSize, io.grpc.Attributes attributes)

Method Summary

Modifier and Type	Method	Description
void	onClose(jakarta.websocket.Session session, jakarta.websocket.CloseReason closeReason)
void	onError(jakarta.websocket.Session session, Throwable error)
void	onMessage(String message)
void	onMessage(ByteBuffer message)
void	onOpen(jakarta.websocket.Session websocketSession, jakarta.websocket.EndpointConfig config)

Methods inherited from class io.grpc.servlet.web.websocket.AbstractWebSocketServerStream

readHeaders

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

GRACEFUL_CLOSE

public static final String GRACEFUL_CLOSE

PATH

public static final io.grpc.Metadata.Key<String> PATH

Custom metadata to hold the path requested by the incoming stream

GRPC_WEBSOCKETS_MULTIPLEX_PROTOCOL

public static final String GRPC_WEBSOCKETS_MULTIPLEX_PROTOCOL

See Also:

• Constant Field Values

Constructor Details

MultiplexedWebSocketServerStream

public MultiplexedWebSocketServerStream(io.grpc.internal.ServerTransportListener transportListener,
 List<? extends io.grpc.ServerStreamTracer.Factory> streamTracerFactories,
 int maxInboundMessageSize,
 io.grpc.Attributes attributes)

Method Details

onOpen

public void onOpen(jakarta.websocket.Session websocketSession,
 jakarta.websocket.EndpointConfig config)

Overrides:

onOpen in class AbstractWebSocketServerStream

onClose

public void onClose(jakarta.websocket.Session session,
 jakarta.websocket.CloseReason closeReason)

Overrides:

onClose in class jakarta.websocket.Endpoint

onMessage

public void onMessage(String message)

Specified by:

onMessage in class AbstractWebSocketServerStream

onMessage

public void onMessage(ByteBuffer message)
               throws IOException

Specified by:

onMessage in class AbstractWebSocketServerStream

Throws:

IOException

onError

public void onError(jakarta.websocket.Session session,
 Throwable error)

Overrides:

onError in class jakarta.websocket.Endpoint