feat: Server sends real Server-Sent-Events

[demos/kafka/chat] / src / main / java / de / juplo / kafka / chat / backend / api / ChatBackendController.java

diff --git a/src/main/java/de/juplo/kafka/chat/backend/api/ChatBackendController.java b/src/main/java/de/juplo/kafka/chat/backend/api/ChatBackendController.java
index 7d1655d..4ce98b2 100644 (file)
--- a/src/main/java/de/juplo/kafka/chat/backend/api/ChatBackendController.java
+++ b/src/main/java/de/juplo/kafka/chat/backend/api/ChatBackendController.java
@@ -2,17 +2,19 @@ package de.juplo.kafka.chat.backend.api;
 
 import de.juplo.kafka.chat.backend.domain.ChatHome;
 import de.juplo.kafka.chat.backend.domain.Chatroom;
+import de.juplo.kafka.chat.backend.persistence.StorageStrategy;
 import lombok.RequiredArgsConstructor;
 import org.springframework.http.MediaType;
+import org.springframework.http.codec.ServerSentEvent;
 import org.springframework.web.bind.annotation.*;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
 import java.time.Clock;
 import java.time.LocalDateTime;
-import java.util.Collection;
 import java.util.Optional;
 import java.util.UUID;
+import java.util.stream.Stream;
 
 
 @RestController
@@ -21,24 +23,25 @@ public class ChatBackendController
 {
   private final ChatHome chatHome;
   private final Clock clock;
+  private final StorageStrategy storageStrategy;
 
 
   @PostMapping("create")
-  public Chatroom create(@RequestBody String name)
+  public ChatroomTo create(@RequestBody String name)
   {
-    return chatHome.createChatroom(name);
+    return ChatroomTo.from(chatHome.createChatroom(name));
   }
 
   @GetMapping("list")
-  public Collection<Chatroom> list()
+  public Stream<ChatroomTo> list()
   {
-    return chatHome.list();
+    return chatHome.list().map(chatroom -> ChatroomTo.from(chatroom));
   }
 
   @GetMapping("get/{chatroomId}")
-  public Optional<Chatroom> get(@PathVariable UUID chatroomId)
+  public Optional<ChatroomTo> get(@PathVariable UUID chatroomId)
   {
-    return chatHome.getChatroom(chatroomId);
+    return chatHome.getChatroom(chatroomId).map(chatroom -> ChatroomTo.from(chatroom));
   }
 
   @PutMapping("put/{chatroomId}/{username}/{messageId}")
@@ -96,10 +99,8 @@ public class ChatBackendController
             .map(message -> MessageTo.from(message));
   }
 
-  @GetMapping(
-      path = "listen/{chatroomId}",
-      produces = MediaType.TEXT_EVENT_STREAM_VALUE)
-  public Flux<MessageTo> listen(@PathVariable UUID chatroomId)
+  @GetMapping(path = "listen/{chatroomId}")
+  public Flux<ServerSentEvent<MessageTo>> listen(@PathVariable UUID chatroomId)
   {
     return chatHome
         .getChatroom(chatroomId)
@@ -107,11 +108,23 @@ public class ChatBackendController
         .orElseThrow(() -> new UnknownChatroomException(chatroomId));
   }
 
-  private Flux<MessageTo> listen(Chatroom chatroom)
+  private Flux<ServerSentEvent<MessageTo>> listen(Chatroom chatroom)
   {
     return chatroom
         .listen()
         .log()
-        .map(message -> MessageTo.from(message));
+        .map(message -> MessageTo.from(message))
+        .map(messageTo ->
+            ServerSentEvent
+                .builder(messageTo)
+                .id(messageTo.getSerial().toString())
+                .event("message")
+                .build());
+  }
+
+  @PostMapping("/store")
+  public void store()
+  {
+    storageStrategy.writeChatrooms(Flux.fromStream(chatHome.list()));
   }
 }