Looking for code for a server side GraphQL subscription listener

Question

I have been looking high and low for some code that will allow me to register to a GraphQL subscription on the server side and read messages, coming from the external subscripti

Answer 1

Figured it out:

const ws = require('ws');
const { WebSocketLink } = require("apollo-link-ws");
const { execute} = require("apollo-link");
const { SubscriptionClient } = require('subscriptions-transport-ws');
const gql = require('graphql-tag');

const serverConfig = {serverUrl:'http://localhost:4000/', subscriptionUrl:'ws://localhost:4000/graphql'};

const client = new SubscriptionClient(serverConfig.subscriptionUrl, {
    reconnect: true
}, ws);

const link = new WebSocketLink(client);

const operation = {
    query: gql`
        subscription eventAdded{
            eventAdded{
                id
                name
                payload
                createdAt
                storedAt
            }
        }`
};

// execute returns an Observable so it can be subscribed to
execute(link, operation).subscribe({
    next: data => console.log(`received data: ${JSON.stringify(data, null, 2)}`),
    error: error => console.log(`received error ${error}`),
    complete: () => console.log(`complete`),
});

console.log(`Listener running at ${new Date().toString()}`);