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Publisher Direct Usage#

The Publisher Direct Usage is a full-featured way to publish messages. It has AsyncAPI representation and includes testable features. This method creates a reusable Publisher object that can be used directly to publish a message:

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from faststream import FastStream
from faststream.kafka import KafkaBroker

broker = KafkaBroker("localhost:9092")
app = FastStream(broker)

publisher = broker.publisher("another-topic")


@broker.subscriber("test-topic")
async def handle():
    await publisher.publish("Hi!")


@broker.subscriber("another-topic")
async def handle_next(msg: str):
    assert msg == "Hi!"


@app.after_startup
async def test():
    await broker.publish("", topic="test-topic")

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from faststream import FastStream
from faststream.rabbit import RabbitBroker

broker = RabbitBroker("amqp://guest:guest@localhost:5672/")
app = FastStream(broker)

publisher = broker.publisher("another-queue")


@broker.subscriber("test-queue")
async def handle():
    await publisher.publish("Hi!")


@broker.subscriber("another-queue")
async def handle_next(msg: str):
    assert msg == "Hi!"


@app.after_startup
async def test():
    await broker.publish("", queue="test-queue")

It is suitable for publishing different messages to different outputs within the same processing function:

@broker.subscriber("in")
async def handle(msg) -> str:
    await publisher1.publish("Response-1")
    await publisher2.publish("Response-2")
Last update: 2023-09-21