Add the sse-websocket module

2026-09-04 00:52:18 +05:30
parent e1f8aa7402
commit 5224afdad2
51 changed files with 2761 additions and 0 deletions
--- a/sse-websocket/src/main/java/com/ankurm/ssews/ChatController.java
+++ b/sse-websocket/src/main/java/com/ankurm/ssews/ChatController.java
@@ -0,0 +1,70 @@
+package com.ankurm.ssews;
+
+import java.security.Principal;
+import java.time.Instant;
+
+import org.springframework.messaging.handler.annotation.MessageMapping;
+import org.springframework.messaging.handler.annotation.Payload;
+import org.springframework.messaging.handler.annotation.SendTo;
+import org.springframework.messaging.simp.SimpMessageHeaderAccessor;
+import org.springframework.messaging.simp.SimpMessageType;
+import org.springframework.messaging.simp.SimpMessagingTemplate;
+import org.springframework.stereotype.Controller;
+
+/**
+ * The chat. Three handlers, each demonstrating a different routing rule.
+ *
+ * @see <a href="../../../../../docs/04-stomp.md">docs/04-stomp.md</a>
+ */
+@Controller
+public class ChatController {
+
+    private final SimpMessagingTemplate template;
+
+    ChatController(SimpMessagingTemplate template) {
+        this.template = template;
+    }
+
+    /** Explicit fan-out destination. Client SENDs to /app/chat.send, subscribers get /topic/room. */
+    @MessageMapping("/chat.send")
+    @SendTo("/topic/room")
+    public ChatMessage send(@Payload ChatMessage in, SimpMessageHeaderAccessor headers) {
+        String from = in.from() == null ? headers.getSessionId() : in.from();
+        return new ChatMessage(from, in.text(), Instant.now());
+    }
+
+    /**
+     * No {@code @SendTo}. The return value still goes somewhere: the default destination is the
+     * broker prefix plus the mapping, i.e. {@code /topic/chat.echo}. That default is why a
+     * handler you thought was private is readable by anyone who guesses the path.
+     */
+    @MessageMapping("/chat.echo")
+    public ChatMessage echo(@Payload ChatMessage in) {
+        return new ChatMessage("echo", in.text(), Instant.now());
+    }
+
+    /**
+     * Point-to-point. Sent to one session's private destination; every other subscriber to
+     * /user/queue/whisper gets nothing, because the broker rewrote the destination per session.
+     *
+     * <p>The three extra lines are not optional and their absence is silent. With no
+     * authenticated {@link Principal} the "user" is the STOMP session id, and
+     * {@code DefaultUserDestinationResolver} can only turn a session id into a real destination
+     * if the message also <em>carries</em> that session id in its headers. Call the two-argument
+     * {@code convertAndSendToUser(sessionId, dest, payload)} instead and the message is resolved
+     * against a user registry that has never heard of that name: no exception, no log line, no
+     * delivery. {@code setLeaveMutable(true)} is required too &mdash; without it the accessor is
+     * immutable by the time the resolver looks, and the session id is lost again.
+     */
+    @MessageMapping("/chat.whisper")
+    public void whisper(@Payload ChatMessage in, SimpMessageHeaderAccessor headers, Principal principal) {
+        String targetSessionId = in.from();
+        SimpMessageHeaderAccessor out = SimpMessageHeaderAccessor.create(SimpMessageType.MESSAGE);
+        out.setSessionId(targetSessionId);
+        out.setLeaveMutable(true);
+        template.convertAndSendToUser(targetSessionId, "/queue/whisper",
+                new ChatMessage(principal == null ? headers.getSessionId() : principal.getName(),
+                        in.text(), Instant.now()),
+                out.getMessageHeaders());
+    }
+}