Salesforce Lightning Platform Event Service Component (Partially Deprecated)

WARNING: this component is partially deprectated.
It is replaced by the official built-in lightning:empApi component in Summer '18. However, the service is still usefull for specific use cases in which lightning:empApi is not supported. These include Communities or Visualforce support.

About

This is a generic and reusable Lightning component that allows to publish and subscribe to platform events. This is a service component so it has no user interface of it's own: it is meant to be called by other components.

Features

The component provides the following features:

• subscribe and publish any platform event
• two deployment modes: as a standalone Lightning component in the App Builder or integrated in markup

Requirements

This component requires that you first install the Server Action Service.

Documentation

The component is documented using Aura documentation.
You can access it from this URL (replace the domain):
https://<YOUR_DOMAIN>.lightning.force.com/auradocs/reference.app#reference?descriptor=c:PicklistService&defType=component

WARNING: there must always be only one instance of this component on a given Lightning page. If there is more than one, there will be errors and inconsistent behavior due to the behavior. This constraint is imposed by the use of the CometD library.

The component can be used in two ways: in a parent component's markup or a standalone Lightning component in the Lightning App Builder.
The 'markup' approach has the advantage of providing callback functions that allow to capture errors with custom handlers.
The 'App Builder' approach has the advantage of enforcing the use of a single shared service instance per Lightning page.

1) Using the service in a component's markup

Start by adding the service in the markup:

<c:PlatformEventService aura:id="peService"/>

Then, use the component's publish and subscribe Aura methods to publish and subscribe to platform events:

const pes = component.find('peService');
pes.publish(eventName, eventData, errors => {
	if (errors) {
		// Optional error handler here (already covered by call to server)
	} else {
		// Notify success
	}
});

2) Using the service as a standalone Lightning component in the App Builder

Drag and drop the platform event service component in a Lightning page using the Lightning App Builder. Notice that the component is 'invisible' (there is a blank space where the component should be), that is normal.

You then have two complementary ways of interacting with the platform event service:

• Static mode: select the component in the App Builder and enter a list of hard-coded platform event names seperated by commas. These will be susbcribed to when the page loads.
• Dynamic mode: fire or handle the following Application events:
  
  

  Event name	Fired by	Handled by	Description
  PlatformEventSubscription	You	Platform Event Service	Event sent to the Platform Event Service in order to subscribe to a platform event
  IncomingPlatformEvent	Platform Event Service	You	Event sent by the Platform Event Service when receiving a platform event
  OutgoingPlatformEvent	You	Platform Event Service	Event sent to the Platform Event Service in order to publish a platform event

Sample application

The default installation installs the component and a sample application available under this URL (replace the domain):
https://<YOUR_DOMAIN>.lightning.force.com/c/SamplePlatformEventApp.app

If you wish to install the project without the sample application, edit sfdx-project.json and remove the src-sample path.