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EventSource

Event Source is currently available through the generators (channels):

Languagesclientserver
TypeScript✔️✔️

All of this is available through AsyncAPI.

Client​

The client generated code is to listen for events from the server and act accordingly.

Server​

The server generated code is to listen for clients making the connection and being ready to receive events.

Channels​

Read more about the channels generator here before continuing.

This generator provides support functions for each resource ensuring you the right payload and parameter are used.

Input (AsyncAPI)Using the code
asyncapi: 3.0.0
info:
  title: Account Service
  version: 1.0.0
  description: This service is in charge of processing user signups
channels:
  userSignups:
    address: user/signedup
    messages:
      userSignedup:
        $ref: '#/components/messages/UserSignedUp'
operations:
  consumeUserSignups:
    action: receive
    channel:
      $ref: '#/channels/userSignups'
components:
  messages:
    UserSignedUp:
      payload:
        type: object
        properties:
          displayName:
            type: string
            description: Name of the user
          email:
            type: string
            format: email
            description: Email of the user

import express, { Router } from 'express'
// Location depends on the payload generator configurations
import { UserSignedup } from './__gen__/payloads/UserSignedup';
// Location depends on the channel generator configurations
import { Protocols } from './__gen__/channels';
const { event_source_client } = Protocols;
const { listenForUserSignedup } = event_source_client;
const listenCallback = async (
  messageEvent: UserSignedUp | null, 
  parameters: UserSignedUpParameters | null,
  error?: string
) => {
  // Do stuff once you receive the event from the server
};
listenForUserSignedup(listenCallback, {baseUrl: 'http://localhost:3000'})

// Use express to listen for clients registering for events
const router = Router()
const app = express()
app.use(express.json({ limit: '3000kb' }))
app.use(express.urlencoded({ extended: true }))
registerSendUserSignedup(router, (req, res, next, parameters, sendEvent) => {
  //Do stuff when client starts listening to the event.
  //For example send a message to the client
  const testMessage = new UserSignedup({displayName: 'test', email: '[email protected]'});
  sendEvent(testMessage);
})
app.use(router)
app.listen(3000)