tessl/maven-micronaut

Modern, JVM-based framework for building modular, easily testable microservice and serverless applications with compile-time DI and fast startup.

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Overview

Eval results

Files

WebSocket Support

Name: tessl/maven-micronaut
Author: tessl

Micronaut provides comprehensive WebSocket support for full-duplex communication between clients and servers, including both server-side endpoints and client-side connections.

Capabilities

Server WebSockets

Create WebSocket endpoints on the server to handle client connections.

/**
 * WebSocket server endpoint
 */
@ServerWebSocket("/ws")
public class ChatWebSocket {
    
    @OnOpen
    public void onOpen(WebSocketSession session) {
        // Handle connection opening
        session.send("Welcome!", MediaType.TEXT_PLAIN_TYPE);
    }
    
    @OnMessage
    public void onMessage(String message, WebSocketSession session) {
        // Handle incoming message
        session.sendSync(message, MediaType.TEXT_PLAIN_TYPE);
    }
    
    @OnClose
    public void onClose(WebSocketSession session, CloseReason closeReason) {
        // Handle connection closing
        System.out.println("Connection closed: " + closeReason.getReasonPhrase());
    }
    
    @OnError
    public void onError(WebSocketSession session, Throwable t) {
        // Handle errors
        t.printStackTrace();
    }
}

Client WebSockets

Create WebSocket clients to connect to remote WebSocket endpoints.

/**
 * WebSocket client
 */
@ClientWebSocket("/ws")
public abstract class ChatClient implements AutoCloseable {
    
    @OnOpen
    public void onOpen(WebSocketSession session) {
        // Handle connection opening
    }
    
    @OnMessage
    public void onMessage(String message) {
        // Handle received message
    }
    
    @OnClose
    public void onClose(CloseReason closeReason) {
        // Handle connection closing
    }
    
    @OnError
    public void onError(Throwable t) {
        // Handle errors
    }
    
    public abstract void send(String message);
    
    public abstract void sendAsync(String message);
}

WebSocket Session Management

Manage WebSocket sessions and broadcast messages to multiple clients.

/**
 * WebSocket session operations
 */
public interface WebSocketSession extends AttributeHolder {
    
    String getId();
    
    Publisher<String> send(Object message, MediaType mediaType);
    
    <T> Publisher<T> send(T message);
    
    void sendSync(Object message, MediaType mediaType);
    
    <T> void sendSync(T message);
    
    boolean isOpen();
    
    boolean isSecure();
    
    Optional<Principal> getUserPrincipal();
    
    Set<WebSocketSession> getOpenSessions();
    
    void close();
    
    void close(CloseReason closeReason);
}

WebSocket Broadcasting

Broadcast messages to multiple WebSocket sessions.

/**
 * WebSocket broadcaster service
 */
@Singleton
public class WebSocketBroadcasterService {
    
    private final WebSocketBroadcaster broadcaster;
    
    public WebSocketBroadcasterService(WebSocketBroadcaster broadcaster) {
        this.broadcaster = broadcaster;
    }
    
    public void broadcastToAll(String message) {
        broadcaster.broadcastSync(message, MediaType.TEXT_PLAIN_TYPE);
    }
    
    public void broadcastToPath(String path, String message) {
        broadcaster.broadcastSync(message, MediaType.TEXT_PLAIN_TYPE, 
            session -> session.getRequestURI().getPath().equals(path));
    }
}

/**
 * WebSocket broadcaster interface
 */
public interface WebSocketBroadcaster {
    
    <T> Publisher<T> broadcast(T message, MediaType mediaType);
    
    <T> Publisher<T> broadcast(T message, MediaType mediaType, 
                               Predicate<WebSocketSession> filter);
    
    <T> void broadcastSync(T message, MediaType mediaType);
    
    <T> void broadcastSync(T message, MediaType mediaType, 
                           Predicate<WebSocketSession> filter);
}

Reactive WebSocket Operations

Use reactive types for WebSocket message handling.

/**
 * Reactive WebSocket endpoint
 */
@ServerWebSocket("/reactive")
public class ReactiveWebSocket {
    
    @OnMessage
    public Publisher<String> onMessage(String message, WebSocketSession session) {
        return Flowable.fromArray(message.split(" "))
            .map(String::toUpperCase);
    }
    
    @OnMessage
    public Single<String> processMessage(String message) {
        return Single.fromCallable(() -> "Processed: " + message);
    }
}

Types

// WebSocket annotations
@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
public @interface ServerWebSocket {
    String value() default "/";
    String[] subprotocols() default {};
}

@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
public @interface ClientWebSocket {
    String value() default "/";
    String[] subprotocols() default {};
}

@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
public @interface OnOpen {
}

@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
public @interface OnMessage {
}

@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
public @interface OnClose {
}

@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
public @interface OnError {
}

// Core WebSocket interfaces
public interface WebSocketSession extends AttributeHolder {
    String getId();
    Publisher<String> send(Object message, MediaType mediaType);
    <T> Publisher<T> send(T message);
    void sendSync(Object message, MediaType mediaType);
    <T> void sendSync(T message);
    boolean isOpen();
    boolean isSecure();
    void close();
    void close(CloseReason closeReason);
}

public interface WebSocketBroadcaster {
    <T> Publisher<T> broadcast(T message, MediaType mediaType);
    <T> Publisher<T> broadcast(T message, MediaType mediaType, Predicate<WebSocketSession> filter);
    <T> void broadcastSync(T message, MediaType mediaType);
    <T> void broadcastSync(T message, MediaType mediaType, Predicate<WebSocketSession> filter);
}

public final class CloseReason {
    public static enum Code {
        NORMAL_CLOSURE, GOING_AWAY, PROTOCOL_ERROR, UNSUPPORTED_DATA, 
        ABNORMAL_CLOSURE, INVALID_PAYLOAD_DATA, POLICY_VIOLATION,
        MESSAGE_TOO_BIG, MANDATORY_EXTENSION, INTERNAL_SERVER_ERROR,
        SERVICE_RESTART, TRY_AGAIN_LATER, BAD_GATEWAY, TLS_HANDSHAKE_FAILURE
    }
    
    public Code getCode();
    public String getReasonPhrase();
}

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