Broadcast Example

Let’s start off in the usual way and create a RabbitMQ communicator and subscribe to receive broadcasts.

import kiwipy
comm = kiwipy.connect('amqp://127.0.0.1')

def subscriber(_comm, body, sender, subject, _corr_id):
    print("Broadcast received:")
    print("sender:\t{}\nsubject:{}\nbody:\t{}\n".format(
        sender, subject, body))


sub_id = comm.add_broadcast_subscriber(subscriber)

Now, let’s broadcast!

comm.broadcast_send(
    body="You'll be making a delivery to Ebola 9 tomorrow",
    sender="The Professor",
    subject="Good news")

Broadcast received:
sender: The Professor
subject:Good news
body:   You'll be making a delivery to Ebola 9 tomorrow

True

True?! That doesn’t sound like good news.

No, no, that’s just the return value from broadcast_send to tell you the message was indeed sent.

Ok, but it’s not exactly the kind of message I wanted to receive.

Sorry about that, here’s how to filter so you only get messages that you’re interested in.

Broadcast Filters

# Remove the current subscriber
comm.remove_broadcast_subscriber(sub_id)
# Add a filtered one
filtered = kiwipy.BroadcastFilter(subscriber)
filtered.add_subject_filter("sell.*")
comm.add_broadcast_subscriber(filtered)

comm.broadcast_send(
    'Tip-top caravan for sale',
    "Bob Jones",
    'sell.caravan')

Broadcast received:
sender: Bob Jones
subject:sell.caravan
body:   Tip-top caravan for sale

True

Hmm, I like me the look of that caravan. Ok, let’s send a purchase request back.

comm.broadcast_send(
    'I need a caravan for me ma',
    sender="Mickey O'Neil",
    subject='purchase.caravan')

True

You can see here we don’t get anything printed because we’re only listening for sell orders.

Finally let’s close the communicator.

comm.close()