Relay is a simple peer-to-peer communication microservice.
On Deno Deploy, Relay can create a world-wide real-time event bus.
Relay can distribute any json-payload, including; app-events, database-updates, or analytics-events.
Relay is stateless, and requires zero configuration. Any message-payload that can be json-stringified, can be published on Relay.
In this pub/sub model, any message published to a channel is immediately
received by all subscribers to that channel. Relay...
- Watches Port 9099 for subscriptions or published messages.
- Streams all published messages to all subscribers using Server Sent Events.
- Leverages Deno-BroadcastChannel to bridge deploy isolates and regions.
To subscribe to Relay messages, we instantiate a new EventSource with a channel name as follows:
// port 9099 is just a convention I use for Relay
const relayURL = `https://localhost:9099/subscribe/?channel="LOG"`;
const relayStream = new EventSource(relayURL);Click here to read more about Subscriptions.
To publish a payload to a channel, we simply use fetch to 'POST' the serialized payload to the Relay service provider (localhost:9099).
NOTE: anything that can be stringified, can be places in the body of the request.
The one exception is that it must contain a string property named channel. This property is used to stream messages to all subscribers of that channel.