Unicorn Adapter

Unicorn Adapter is a node library to help subscribe to events in the event processing platform Unicorn.

Getting started

npm install unicorn-adapter to install the package

const UnicornAdapter = require('unicorn-adapter');

let unicornAdapter = new UnicornAdapter("Your Unicorn Url", "Your callback Url", options);

Available options:

• maxTries - Number of retries

Subscribe to events

let uuid;
unicornAdapter.subscribeToEvent('EventType').then(subscriptionId => {
    uuid = subscriptionUuid;
    console.log(`Subscription UUID: ${ subscriptionId }`);
});

unicornAdapter.unsubscribeFromEvent(uuid);

Publish events

const exampleEventType = 'exampleEventType';
const exampleEvent = {
  key1: 'value1',
  key2: 'value2'
};

// Sent event to Unicorn
unicornAdapter.generateEvent(exampleEvent, exampleEventType).then(eventId => {
  console.log(`EventId: ${ eventId }`);
});

// Adds TimeStamp and DO_state to event before sending event to Unicorn
unicornAdapter.generateChimeraEvent(exampleEvent, exampleEventType, 'state1').then(eventId => {
  console.log(`EventId: ${ eventId }`);
});

More details

UnicornAdapter(unicornUrl, callbackUrl, options)

• Initialize a new UnicornAdapter instance.
• Requires the Unicorn url, a callback url and an options object. Currently the only supported option is maxTries, which determines how often creating a notification rule should be retried before giving up.

subscribeToEvent(eventName, attributes = ['*'], filters = {}, callbackUrl)

• Subscribes to a Unicorn event of event type eventName.
• attributes is an array of attribute names which are included in the notification payload.
• filters allow to better filter events using the esper-language package.
• callbackUrl is optional and overwrites the callback url set on initialisation.
• returns a Promise resolving to the UUID of the notification rule created in Unicorn

unsubscribeFromEvent(uuid)

• Deletes the notification rule with the given UUID in Unicorn
• returns empty Promise, which resolves after successful deletion or rejects otherwise

generateEvent(event, eventType, dataObjectState = '')

• generates event in Unicorn
• event is a JSON object that should match the structure defined by the event type definition
• automatically converts event to XML, that's understandable by Unicorn
• eventType is the event type of the event, which is needed by Unicorn
• dataObjectState is only helpful when working with Chimera. It is just a shortcut for setting the DO_state attribute of an event

Authors

• Marius Lichtblau - mlichtblau - lichtblau.io - @lichtblau