release: WRNexusJS 0.8.0

packages/pubsub/src/brokers.ts

@@ -0,0 +1,59 @@
+import type { Handler, PubSubDriver } from "./index.ts";
+
+export interface NatsClient {
+  publish(subject: string, data: Uint8Array): void | Promise<void>;
+  subscribe(subject: string, handler: (data: Uint8Array, subject: string) => void): () => void;
+  close?(): void | Promise<void>;
+}
+
+export function natsDriver(client: NatsClient): PubSubDriver {
+  const encoder = new TextEncoder();
+  const decoder = new TextDecoder();
+  return {
+    publish(topic, message) {
+      return client.publish(topic, encoder.encode(JSON.stringify(message)));
+    },
+    subscribe(pattern, handler) {
+      const subject =
+        pattern === "*" ? ">" : pattern.endsWith(":*") ? `${pattern.slice(0, -2)}:>` : pattern;
+      return client.subscribe(subject, (data, topic) => {
+        const raw = decoder.decode(data);
+        let value: unknown = raw;
+        try {
+          value = JSON.parse(raw);
+        } catch {
+          /* raw broker payload */
+        }
+        void handler(value, topic);
+      });
+    },
+    close: () => client.close?.(),
+  };
+}
+
+export interface KafkaClient {
+  publish(topic: string, value: string): void | Promise<void>;
+  subscribe(pattern: string, handler: (value: string, topic: string) => void): () => void;
+  close?(): void | Promise<void>;
+}
+
+/** Kafka adapter contract; consumer-group/rebalance policy remains owned by the selected client. */
+export function kafkaDriver(client: KafkaClient): PubSubDriver {
+  return {
+    publish(topic, message) {
+      return client.publish(topic, JSON.stringify(message));
+    },
+    subscribe(pattern, handler: Handler) {
+      return client.subscribe(pattern, (raw, topic) => {
+        let value: unknown = raw;
+        try {
+          value = JSON.parse(raw);
+        } catch {
+          /* raw broker payload */
+        }
+        void handler(value, topic);
+      });
+    },
+    close: () => client.close?.(),
+  };
+}