python API for get_matched_publications

[jeffpg144]

I've searched the python code and documentation but can't find how to access the following cyclonedds c API.

https://cyclonedds.io/docs/cyclonedds/latest/api/builtin.html?highlight=get_matched#c.dds_get_matched_publications

Is this API missing from python? If missing, is there a work around or would you consider adding it.

Thanks.

[Splinter1984]

Hi @jeffpg144. Currently this function of C API is not supported in Python. But you can implement the same behavior by using listeners with on_subscription_matched callback.

from cyclonedds.core import Listener, Qos
from cyclonedds.domain import DomainParticipant
from cyclonedds.topic import Topic
from cyclonedds.pub import DataWriter
from cyclonedds.sub import DataReader
from msg import Msg

class SubMatchedListener(Listener):
    def on_subscription_matched(self, reader, status):
        # optionally you can store `instance_handle`s to have access to information about matching writers in a future.
        print(f"<< act ih: {status.last_publication_handle}")

listener = SubMatchedListener()
qos = Qos()
domain_participant = DomainParticipant()
topic = Topic(domain_participant, 'topic', Msg, qos=qos)
reader = DataReader(domain_participant, topic, listener=listener)

writers = []
msg = Msg(data=1)
for i in range(0, 5):
    writers.append(DataWriter(domain_participant, topic, qos))
    writers[i].write(msg)
    print(f">> exp ih: {writers[i].get_instance_handle()}")

[jeffpg144]

Thanks, I'll give it a try.