This repository contains an Python 3 example of how to use the Darwin v16 messages from the National Rail Open Data platform, located at the following URL:
Due to a breaking change between Python 3.11 and Python 3.12, the
pyxbgen command will fail with the following error:
AttributeError: module 'collections' has no attribute 'MutableSequence'
Until the GitHub issue at renalreg/PyXB-X#13 is resolved, please do not use Python 3.12 to run this code.
To use this service, you will need to sign up for a free account and subscribe to the 'Darwin' feed.
Edit opendata-nationalrail-client.py and set the USERNAME, PASSWORD,
HOSTNAME and HOSTPORT variables to the values shown in 'Username', 'Password',
'Messaging host' and 'STOMP Port' on the 'My Feeds' page.
Leave CLIENT_ID set to socket.getfqdn() - this will use the hostname of your
client for the durable subscription. You may need to change this to something
else if you want to fail over the subscription to a different client. In this
case, you could use your username.
The HEARTBEAT_INTERVAL_MS is set by default to 15 seconds (15,000ms) - this
should be sufficient for almost every application. Don't change it unless you
have a good reason to do so.
RECONNECT_DELAY_SECS will enforce a 15-second delay before exiting. This will
let you run the client in a loop, such as through a shell script, and protect
against you accidentally degrading the service for everyone by reconnecting far
too frequently.
Finally, install the required dependencies by running pip install -r requirements.txt.
The messages are produced in XML format, and a good way to consume them is by using generated classes with PyXB.
pyxbgen --schema-root=ppv16 --module PPv16 rttiPPTSchema_v16.xsd
The opendata-nationalrail-client.py script will show the raw message body and
print the timestamp from the parsed XML through the classes generated by
PyXB.
The stomp library is quite verbose in its logging, but you should see output
similar to the following:
2022-08-22 10:54:00,778 INFO attempt reconnection (True, None, 0)
2022-08-22 10:54:00,778 INFO Attempting connection to host darwin-dist-44ae45.nationalrail.co.uk, port 61613
2022-08-22 10:54:00,803 INFO Established connection to host darwin-dist-44ae45.nationalrail.co.uk, port 61613
2022-08-22 10:54:00,804 INFO Starting receiver loop (<Thread(Thread-1, started daemon 140347258906368)>)
2022-08-22 10:54:00,804 INFO Created thread <Thread(Thread-1, started daemon 140347258906368)> using func <function default_create_thread at 0x7fa52555c4c0>
2022-08-22 10:54:00,804 INFO Connecting to darwin-dist-44ae45.nationalrail.co.uk
2022-08-22 10:54:00,804 INFO Sending frame: 'STOMP'
2022-08-22 10:54:00,822 INFO Received frame: 'CONNECTED', len(body)=0
2022-08-22 10:54:00,823 INFO Sending frame: 'SUBSCRIBE'
2022-08-22 10:54:00,823 INFO Starting heartbeat loop
2022-08-22 10:54:00,846 INFO Received frame: 'MESSAGE', len(body)=467
2022-08-22 10:54:00,846 INFO {cmd=MESSAGE,headers=[{'content-length': '467', 'expires': '1661162040963', 'destination': '/topic/darwin.pushport-v16', 'CamelJmsDeliveryMode': '1', 'subscription': '1', 'priority': '4', 'breadcrumbId': 'ID-nrdp-prod-01-dsg-caci-co-uk-1661027611761-0-14496036', 'Content_HYPHEN_Type': 'application/xml', 'Username': 'thales', 'SequenceNumber': '702508', 'message-id': 'ID:nrdp-prod-01.dsg.caci.co.uk-43581-1661027612860-6:238:1:1:704479', 'PushPortSequence': '5502748', 'MessageType': 'TS', 'timestamp': '1661161640963'}],body=b'\x1f\x8b\x08\x00\x00\x00\x00\x00\x00\x00\x9d\x94Qo\x9b0\x10\xc7\xbf\x8a\xe5\xd7)\x01;!\x01\x14\xa8\xb2F\x95"m*\x02\xa6\xf6\xad\xb2\xc0J\x90\x003\xfb\x9cl\xdf~GHK\xd9\x1bE\xc2\xba;\xdf\xff\xc7\x9d\xe5c\xf7\xf0\xa7\xa9\xc9EjS\xa96\xa2l\xe9R"\xdbB\x95U{\x8a\xe8\xaf\xfci\xe1Sb@\xb4\xa5\xa8U+#\xfaW\x1a\xfa\x10\xef\x92Ni \xa8mMD\xcf\x00]\xe88\xd7\xebu\tgQKs\xd2\xcav\xcbB5\x8e\x06\xa8\x9c\xc4\x9as\x82\xf9\xce\x85m\xe8 \n[\xc3g\x08\xb3\xe2,K\x8b\t\xcee5\x12V_#\xf0\x91\xb0\x9eAxR\xba\x11\x80\xc74Ex\xf3\x10\xb2\x10\x06\xa6ml\xbeX\x04\x1b\x11\xdb9\'\x017\xc0Oi\x8c8\xc9)\xc7\x9f\xc1\xc9\xb5\xa8\xda}-5L\x19\xc1\\\xc6\xb3.\xa5\x9e \x98;\x87q8\x08\x10S=\x9b\xa1\xdf\xd7B7\xd3\x16\xd8x7\xff\xd7\xa6y~\xfc\xd0\xf6Gi\x8d\xa3\x95\x827\x94\x03\xce\x02w9_\xb8\xfe\x82\xf3\x9c\xb9\xe1z\x1brw\xe9\xf9\x81\xbf\n\xb6\xdf\\\x16\xba8_\xe3\xb4mp\xdc\xe2\x9dM\x89\xedJ\x01\xf2YW\xa7\n\xe3\x8f\xc7\x8c\x12-\x7f[i SV\x178w\xafi\xfa\xf8\x11<\x1e\xf0C\xdc\xf5\xf1\xbd=\x01[\x05\x08\xca3\xa2\xabr\xa8\xa1\xdf\xf4]\x9fq/\xa0\xc4\xf6\xd1\xe4\xee\x18S~.\x13ux\x89\xc3\x1f\xaa\xb8]\x0b\x02]\x1d\xd1\xfd\xf7\x97\xc3kJ\xc9\x15\x04\x96\xe9\x85lKI7\xda\x83DhM$`\xcc\x0f=\xdc\x97\xd0\xf4\xc5\xdf=\xa3\x8b{#h\x1d[\x03\xf7\x16\x9cA\xdb\xd5\x02H\xbf\x18\xdbE\x14\xb4\x95\x94\x14\x95I&\x91x\xbds\xde\x93\xe3\xc1|/\x13\xdd<\xc3\xc5\xa6\xb8\xdc~F\xf1?g\x8dwp\xcb\x04\x00\x00'}
2022-08-22 10:54:00,846 INFO Message sequence=702508, type=TS received
2022-08-22 10:54:00,894 INFO Successfully received a Darwin Push Port message from 2022-08-22 09:47:20.589840+00:00
To adapt this code for your own purposes, extend the on_message() method and process the contents of the obj
created.
For support and questions with using Darwin, please use the forum at the following URL:
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