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:

• https://opendata.nationalrail.co.uk/

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 stomp.py pyxb.

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.

For support and questions with using Darwin, please use the forum at the following URL:

• https://groups.google.com/group/openraildata-talk