Download WebSocket in Java EE

WebSocket in Java EE
Štěpán Kopřiva
[email protected]
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Agenda
ñ  WebSocket Protocol
ñ  Protocol Analysis and Usage
ñ  WebSocket API for Java
ñ  Project Tyrus
ñ  Demo
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WebSocket Protocol
ñ  IETF RFC 6455 Standard
ñ  Bi – directional, full duplex communication
ñ  One TCP connection
ñ  Stream of messages
ñ  Communication over standard TCP port 80
ñ  ws:// and wss://
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Establish a Connection
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Handshake Request
Handshake Request
Http Request!
GET /endpoint HTTP/1.1!
Host: server.example.com!
Upgrade: websocket!
Connection: Upgrade!
Sec-WebSocket-Key: x3JJHMbDL1EzLkh9GBhXDw==!
Sec-WebSocket-Protocol: megachat, chat!
Sec-WebSocket-Extensions : compress, mux!
Sec-WebSocket-Version: 13!
Origin: http://example.com!
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Handshake Response
Handshake Response
Http Response!
HTTP/1.1 101 Switching Protocols!
Upgrade: websocket!
Connection: Upgrade!
Sec-WebSocket-Accept: HSmrc0sMlYUkAGmm5OPpG2HaGWk=!
Sec-WebSocket-Protocol: chat!
Sec-WebSocket-Extensions: compress, mux!
!
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Establish a connection
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WebSocket Events & Lifecycle
ñ  Open
ñ  Message
ñ  Error
ñ  Close
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WebSocket Pros & Cons (vs. HTTP)
ñ  Small message size (small overhead)
ñ  Decreased latency
ñ  Useful for following applications:
ñ  Small messages (updates)
ñ  A lot of messages
ñ  Ticker update, games, chat
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WebSocket vs. AJAX experiment
ñ  Localhost
ñ  AJAX: 1000 iterations in 2.934 s
ñ  WS: 1000 iterations in 0.466 s
ñ  England - California
ñ  AJAX: 1000 iterations in 263.7 s
ñ  WS: 1000 iterations in 227.7 s
ñ  http://www.peterbe.com/plog/arewebsockets-faster-than-ajax
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WebSocket Scalability
ñ  Extension which
ñ  Separates logical connection from physical one
ñ  Allows multiple logical connections to share
physical connection
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JSR 356 Java API for Web Socket
ñ  Specification
ñ 
ñ 
ñ 
ñ 
http://jcp.org/en/jsr/detail?id=356
http://java.net/projects/websocket-spec
Early Draft Review
Will be in Java EE 7
ñ  Reference Implementation
ñ  http://tyrus.java.net
ñ  Bundled in latest Glassfish 4 builds
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JSR 356 Java API for Web Socket
ñ  Package javax.websocket
ñ  Annotated API
ñ  Programmatic API
ñ  Client API
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Hello World Server - Annotated
@WebSocketEndpoint(value=“/hello”)
public class HelloServer {
@WebSocketMessage
public void onMessage(String message, Session session) {
session.getRemote().sendString(“Hello ”+text);
}
}
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Main API classes
Endpoint
MessageHandler
RemoteEndpoint
Session
Intercepts websocket lifecycle events
Handles all incoming messages for an
Endpoint
Represents the ‘other end’ of this
conversation
Represents the active conversation
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Object Model: Server Side
MessageHandler
MessageHandler
MessageHandler
Server
RemoteEndpoint
Client
Session
Endpoint
Session
Client
RemoteEndpoint
MessageHandler
MessageHandler
MessageHandler
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WebSocketEndpoint Annotation
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.TYPE)
public @interface WebSocketEndpoint {
public String value();
public String[] subprotocols() default {};
public Class<? extends Decoder>[] decoders() default {};
public Class<? extends Encoder>[] encoders() default {};
}
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WebSocketMessage Annotation
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface WebSocketMessage {
public long maxMessageSize() default -1;
}
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Other Method Annotations
ñ  WebSocketOpen
ñ  WebSocketClose
ñ  WebSocketError
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Hello World Server - Programmatic
public class HelloServer extends Endpoint {
@Override
public void onOpen(Session session) {
session.addMessageHandler(new MessageHandler.Basic<String> {
public void onMessage(String text) {
session.getRemote().sendString(“Hello ”+text);
}
});
}
...
}
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Endpoint
public abstract class Endpoint {
public abstract EndpointConfiguration
getEndpointConfiguration();
public abstract void onOpen(Session session);
public void onClose(CloseReason closeReason) { }
public void onError(Throwable thr) { }
}
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Endpoint Configuration
public interface EndpointConfiguration {
List<Encoder> getEncoders();
List<Decoder> getDecoders();
}
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Session
public interface Session {
RemoteEndpoint getRemote();
void addMessageHandler(MessageHandler listener);
Set<MessageHandler> getMessageHandlers();
void removeMessageHandler(MessageHandler listener);
void close() throws IOException;
...
}
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RemoteEndpoint
public interface RemoteEndpoint {
void sendString(String text) throws IOException;
void sendBytes(ByteBuffer data) throws IOException;
void sendPartialString(String fragment, boolean isLast)
throws IOException;
void sendPartialBytes(ByteBuffer partialByte, boolean
isLast) throws IOException;
void sendObject(Object o) throws IOException,;
}
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Hello Client - Programmatic
Client
MessageHandler
MessageHandler
MessageHandler
Endpoint
Session
RemoteEndpoint
Server
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Hello World Client
public class HelloClient extends Endpoint {
@Override
public void onOpen(Session session) {
session.addMessageHandler(new MessageHandler.Basic<String> {
public void onMessage(String text) {
System.out.println(“Server said: ”+text);
}
});
session.getRemote().sendString(“Peter”);
}
...
}
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Draw Server Demo
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Thank You!
ñ  Give it a try
ñ  http://tyrus.java.net
ñ  https://github.com/jersey/hol-sse-websocket
ñ  Specification
ñ 
ñ 
ñ 
ñ 
http://jcp.org/en/jsr/detail?id=356
http://java.net/projects/websocket-spec
Early Draft Review
Will be in Java EE 7
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