[feat][client] Expose message schema version

index.d.ts

@@ -194,6 +194,11 @@ export class Message {
   getProducerName(): string;
   isReplicated(): boolean;
   getReplicatedFrom(): string;
+  /**
+   * The version of the schema the producer used to serialize this message,
+   * or `null` if the message carries no schema version.
+   */
+  getSchemaVersion(): number | null;
   getEncryptionContext(): EncryptionContext | null;
 }
 

src/Message.cc

@@ -65,6 +65,7 @@ Napi::Object Message::Init(Napi::Env env, Napi::Object exports) {
        InstanceMethod("getProducerName", &Message::GetProducerName),
        InstanceMethod("isReplicated", &Message::IsReplicated),
        InstanceMethod("getReplicatedFrom", &Message::GetReplicatedFrom),
+       InstanceMethod("getSchemaVersion", &Message::GetSchemaVersion),
        InstanceMethod("getEncryptionContext", &Message::GetEncryptionContext)});
 
   constructor = Napi::Persistent(func);
@@ -197,6 +198,19 @@ Napi::Value Message::GetReplicatedFrom(const Napi::CallbackInfo &info) {
   return Napi::String::New(env, replicatedFrom);
 }
 
+Napi::Value Message::GetSchemaVersion(const Napi::CallbackInfo &info) {
+  Napi::Env env = info.Env();
+  if (!ValidateCMessage(env)) {
+    return env.Null();
+  }
+
+  const pulsar::Message &message = this->cMessage.get()->message;
+  if (!message.hasSchemaVersion()) {
+    return env.Null();
+  }
+  return Napi::Number::New(env, message.getLongSchemaVersion());
+}
+
 Napi::Value Message::GetEncryptionContext(const Napi::CallbackInfo &info) {
   Napi::Env env = info.Env();
   if (!ValidateCMessage(env)) {

src/Message.h

@@ -48,6 +48,7 @@ class Message : public Napi::ObjectWrap<Message> {
   Napi::Value GetProducerName(const Napi::CallbackInfo &info);
   Napi::Value IsReplicated(const Napi::CallbackInfo &info);
   Napi::Value GetReplicatedFrom(const Napi::CallbackInfo &info);
+  Napi::Value GetSchemaVersion(const Napi::CallbackInfo &info);
   Napi::Value GetRedeliveryCount(const Napi::CallbackInfo &info);
   Napi::Value GetEncryptionContext(const Napi::CallbackInfo &info);
   bool ValidateCMessage(Napi::Env env);

tests/end_to_end.test.js

@@ -178,6 +178,70 @@ const Pulsar = require('../index');
       await client.close();
     });
 
+    test('getSchemaVersion', async () => {
+      const client = new Pulsar.Client({
+        serviceUrl: 'pulsar://localhost:6650',
+        operationTimeoutSeconds: 30,
+      });
+
+      const schemaV1 = {
+        schemaType: 'Json',
+        schema: JSON.stringify({
+          type: 'record',
+          name: 'User',
+          fields: [{ name: 'name', type: 'string' }],
+        }),
+      };
+      // Compatible evolution of schemaV1: adds a field with a default.
+      const schemaV2 = {
+        schemaType: 'Json',
+        schema: JSON.stringify({
+          type: 'record',
+          name: 'User',
+          fields: [
+            { name: 'name', type: 'string' },
+            { name: 'age', type: 'int', default: 0 },
+          ],
+        }),
+      };
+
+      const topic = `persistent://public/default/schema-version-${Date.now()}`;
+      const consumer = await client.subscribe({
+        topic,
+        subscription: 'sub1',
+        schema: schemaV1,
+      });
+
+      const producerV1 = await client.createProducer({ topic, schema: schemaV1 });
+      await producerV1.send({ data: Buffer.from(JSON.stringify({ name: 'alice' })) });
+      const msgV1 = await consumer.receive();
+      consumer.acknowledge(msgV1);
+
+      const producerV2 = await client.createProducer({ topic, schema: schemaV2 });
+      await producerV2.send({ data: Buffer.from(JSON.stringify({ name: 'bob', age: 30 })) });
+      const msgV2 = await consumer.receive();
+      consumer.acknowledge(msgV2);
+
+      expect(msgV1.getSchemaVersion()).toBe(0);
+      expect(msgV2.getSchemaVersion()).toBe(1);
+
+      const bytesTopic = `persistent://public/default/schema-version-bytes-${Date.now()}`;
+      const bytesConsumer = await client.subscribe({ topic: bytesTopic, subscription: 'sub1' });
+      const bytesProducer = await client.createProducer({ topic: bytesTopic });
+      await bytesProducer.send({ data: Buffer.from('no-schema') });
+      const bytesMsg = await bytesConsumer.receive();
+      bytesConsumer.acknowledge(bytesMsg);
+
+      expect(bytesMsg.getSchemaVersion()).toBeNull();
+
+      await producerV1.close();
+      await producerV2.close();
+      await consumer.close();
+      await bytesProducer.close();
+      await bytesConsumer.close();
+      await client.close();
+    });
+
     test('Produce/Consume Listener', async () => {
       const client = new Pulsar.Client({
         serviceUrl: 'pulsar://localhost:6650',

tstest.ts

@@ -309,6 +309,7 @@ import Pulsar = require('./index');
   const redeliveryCount: number = message1.getRedeliveryCount();
   const isReplicated: boolean = message1.isReplicated();
   const replicatedFrom: string = message1.getReplicatedFrom();
+  const schemaVersion: number | null = message1.getSchemaVersion();
   const partitionKey: string = message1.getPartitionKey();
 
   const message3: Pulsar.Message = await reader1.readNext();