跳转至

混合应用程序

混合应用程序既侦听 HTTP 请求，又利用连接的微服务。 INestApplication 实例可以通过 connectMicroservice() 方法连接到 INestMicroservice 实例。

1
2
3
4
5
6
7
const app = await NestFactory.create(AppModule);
const microservice = app.connectMicroservice({
  transport: Transport.TCP,
});

await app.startAllMicroservices();
await app.listen(3001);

To connect multiple microservice instances, issue the call to connectMicroservice() for each microservice:

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
const app = await NestFactory.create(AppModule);
// microservice #1
const microserviceTcp = app.connectMicroservice<MicroserviceOptions>({
  transport: Transport.TCP,
  options: {
    port: 3001,
  },
});
// microservice #2
const microserviceRedis = app.connectMicroservice<MicroserviceOptions>({
  transport: Transport.REDIS,
  options: {
    url: 'redis://localhost:6379',
  },
});

await app.startAllMicroservices();
await app.listen(3001);

To bind @MessagePattern() to only one transport strategy (for example, MQTT) in a hybrid application with multiple microservices, we can pass the second argument of type Transport which is an enum with all the built-in transport strategies defined.

1
2
3
4
5
6
7
8
9
@MessagePattern('time.us.*', Transport.NATS)
getDate(@Payload() data: number[], @Ctx() context: NatsContext) {
  console.log(`Subject: ${context.getSubject()}`); // e.g. "time.us.east"
  return new Date().toLocaleTimeString(...);
}
@MessagePattern({ cmd: 'time.us' }, Transport.TCP)
getTCPDate(@Payload() data: number[]) {
  return new Date().toLocaleTimeString(...);
}

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
@Bind(Payload(), Ctx())
@MessagePattern('time.us.*', Transport.NATS)
getDate(data, context) {
  console.log(`Subject: ${context.getSubject()}`); // e.g. "time.us.east"
  return new Date().toLocaleTimeString(...);
}
@Bind(Payload(), Ctx())
@MessagePattern({ cmd: 'time.us' }, Transport.TCP)
getTCPDate(data, context) {
  return new Date().toLocaleTimeString(...);
}

Hint

@Payload(), @Ctx(), Transport and NatsContext are imported from @nestjs/microservices.

Sharing configuration

By default a hybrid application will not inherit global pipes, interceptors, guards and filters configured for the main (HTTP-based) application. To inherit these configuration properties from the main application, set the inheritAppConfig property in the second argument (an optional options object) of the connectMicroservice() call, as follow:

1
2
3
4
5
6
const microservice = app.connectMicroservice(
  {
    transport: Transport.TCP,
  },
  { inheritAppConfig: true },
);