Sample Stomp message queue consumer code for Fedora

example-response.json

--Headers: {
		"destination": "/topic/fedora",
		"expires": "0",
		"message-id": "ID:wikibase-36143-1638450997244-4:1:1:1:6",
		"org.fcrepo.jms.baseURL": "http://141.94.169.145:8080/rest",
		"org.fcrepo.jms.eventID": "urn:uuid:cd36ab67-4a51-4e88-96ab-b07acf71d625",
		"org.fcrepo.jms.eventType": "https://www.w3.org/ns/activitystreams#Create",
		"org.fcrepo.jms.identifier": "/galaxy",
		"org.fcrepo.jms.resourceType": "http://mementoweb.org/ns#TimeGate,http://www.w3.org/ns/ldp#BasicContainer,http://fedora.info/definitions/v4/repository#Resource,http://mementoweb.org/ns#OriginalResource,http://www.w3.org/ns/ldp#Container,http://www.w3.org/ns/ldp#Resource,http://www.w3.org/ns/ldp#RDFSource,http://fedora.info/definitions/v4/repository#Container",
		"org.fcrepo.jms.timestamp": "1638519905399",
		"org.fcrepo.jms.user": "null",
		"org.fcrepo.jms.userAgent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/96.0.4664.45 Safari/537.36",
		"persistent": "true",
		"priority": "4",
		"subscription": "abcd",
		"timestamp": "1638519905410"
	}

	--Body: {
		"id": "urn:uuid:cd36ab67-4a51-4e88-96ab-b07acf71d625",
		"type": ["Create"],
		"name": "create resource",
		"published": "2021-12-03T08:25:05.399035Z",
		"actor": [{
			"type": "Person",
			"id": "null"
		}, {
			"type": "Application",
			"name": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/96.0.4664.45 Safari/537.36"
		}],
		"object": {
			"type": ["http://mementoweb.org/ns#TimeGate", "http://www.w3.org/ns/ldp#BasicContainer", "http://fedora.info/definitions/v4/repository#Resource", "http://mementoweb.org/ns#OriginalResource", "http://www.w3.org/ns/ldp#Container", "http://www.w3.org/ns/ldp#Resource", "http://www.w3.org/ns/ldp#RDFSource", "http://fedora.info/definitions/v4/repository#Container", "http://www.w3.org/ns/prov#Entity"],
			"id": "http://141.94.169.145:8080/rest/galaxy",
			"isPartOf": "http://141.94.169.145:8080/rest"
		},
		"@context": ["https://www.w3.org/ns/activitystreams#", {
			"prov": "http://www.w3.org/ns/prov#",
			"dcterms": "http://purl.org/dc/terms/",
			"type": "@type",
			"id": "@id",
			"isPartOf": {
				"@id": "dcterms:isPartOf",
				"@type": "@id"
			}
		}]
	}

stomp-consumer.py

"""Fedora listener

Listens for ActiveMQ messages using the stomp message queue library.

The equivalent using stomp itself would look as follows;

    stomp -H localhost -P 61613
    > subscribe /topic/fedora

Modified from Lyrasis:

    * https://wiki.lyrasis.org/display/FEDORAM6M1P0/Inspect+Event+Messages
"""
import json
import stomp
import signal


class Listener(stomp.ConnectionListener):
    def on_message(self, frames):
        print("\n\nIncoming Message")
        print("--Headers:")
        print(json.dumps(frames.headers, indent=2, sort_keys=True))
        print("\n--Body:")
        print(json.dumps(frames.body, indent=2, sort_keys=True))


connection = stomp.Connection(host_and_ports=[("localhost", 61613)])
connection.set_listener("", Listener())
connection.connect()
connection.subscribe(id="abcd", destination="/topic/fedora")
while True:
    signal.pause()

Question is, how does one provide a retroactive argument? Further, is fcrepo configured to store messages so that they can be retroactively sent out? e.g. one possibility? headers={"activemq.retroactive": "true"}

• Subscribe function in stomp.py.