Client

Kind: Function

Source: packages/microservices/decorators/client.decorator.ts

Attaches the ClientProxy instance to the given property

Client() is a property decorator that attaches a ClientProxy instance to a class property. It registers the supplied microservice client options so the application can create and use a transport-specific proxy for sending messages or emitting events to another service.

Signature

ts
function Client(metadata: ClientOptions): PropertyDecorator

Parameters

Name	Type
`metadata`	`ClientOptions`

Returns: PropertyDecorator

Diagram

mermaid
graph LR
  A[Service class property] --> B["@Client(clientOptions)"]
  B --> C[ClientProxy configuration metadata]
  C --> D[ClientProxy instance]
  D --> E[Remote microservice transport]

Usage

ts
import { Injectable } from '@nestjs/common';
import { Client, ClientProxy, Transport } from '@nestjs/microservices';

@Injectable()
export class OrdersService {
  @Client({
    transport: Transport.TCP,
    options: {
      host: 'localhost',
      port: 3001,
    },
  })
  private readonly inventoryClient: ClientProxy;

  async reserveInventory(productId: string, quantity: number) {
    return this.inventoryClient.send(
      { cmd: 'reserve_inventory' },
      { productId, quantity },
    );
  }
}

AI Coding Instructions

Apply @Client() only to class properties intended to hold a ClientProxy; declare the property type as ClientProxy.
Provide transport-specific configuration through the decorator options, including required connection details such as host, port, queue, or broker URLs.
Use client.send() for request-response messaging and client.emit() for event-based communication.
Ensure the target microservice is configured with the same transport and compatible message patterns.
Avoid manually constructing client proxies when decorator-based property injection is sufficient; keep client configuration close to the consuming service.

Used by

11 references from 11 files. Each is a place in this repository where the symbol is actually used — go read one rather than trusting an example.

Imported by (11)

AppController — integration/microservices/src/app.controller.ts:20
GrpcController — integration/microservices/src/grpc/grpc.controller.ts:21
AdvancedGrpcController — integration/microservices/src/grpc-advanced/advanced.grpc.controller.ts:14
KafkaController — integration/microservices/src/kafka/kafka.controller.ts:15
KafkaConcurrentController — integration/microservices/src/kafka-concurrent/kafka-concurrent.controller.ts:24
MqttBroadcastController — integration/microservices/src/mqtt/mqtt-broadcast.controller.ts:11
MqttController — integration/microservices/src/mqtt/mqtt.controller.ts:16
NatsBroadcastController — integration/microservices/src/nats/nats-broadcast.controller.ts:11

…and 3 more.