Apollo Subscriptions: Apollo Graphql is receiving updates on Playground but not on client

Question

I'm using react on Apollo GraphQL subscriptions and I can receive updates on Apollo Playground but not on Client. Here is the response on the Apollo Playground:

Graphql Server is on http://localhost:4000/ and subscriptions on ws://localhost:4000/graphql. However, it works on the playground but not on client-side. I have set up Apollo client in this manner to receive updates from server:

import ApolloClient from 'apollo-boost';
import { WebSocketLink } from 'apollo-link-ws';
import { HttpLink } from 'apollo-link-http';
import { split } from 'apollo-link';
import { getMainDefinition } from 'apollo-utilities';

const httpLink = new HttpLink({
  uri: 'http://localhost:4000/graphql'
});

export const wsLink = new WebSocketLink({
  uri: `ws://localhost:4000/graphql`,
  options: {
    reconnect: false
  }
});

export const link = split(
  // split based on operation type
  ({ query }) => {
    const definition = getMainDefinition(query);
    return (
      definition.kind === 'OperationDefinition' &&
      definition.operation === 'subscription'
    );
  },
  wsLink,
  httpLink,
);



export const client = new ApolloClient({
  uri: 'http://localhost:4000/',
});

In my view I have used useSubscriptions:

const MESSAGE_SENT_SUBSCRIPTION =  gql`subscription {
  messageSent {
    id
    message
  }
}`
const {data: newMessage, loading: newMessageLoading} = useSubscription(MESSAGE_SENT_SUBSCRIPTION, {});

And on render, I have used:

{!newMessageLoading && JSON.stringify(newMessage)}

But from client, it doesn't receive updates but I am sure that it connects with Graphql WebSockets server.

Server Side:

let database = require("./src/database.js")
let schema = require("./src/schema.js");
let resolvers = require("./src/resolvers.js");
let {ApolloServer} = require("apollo-server");

// The ApolloServer constructor requires two parameters: your schema
// definition and your set of resolvers.
const server = new ApolloServer({ 
  typeDefs: schema, 
  resolvers: resolvers,
  context: {
    database
  }
});

// The `listen` method launches a web server.
server.listen().then(({ url,subscriptionsUrl ,subscriptionsPath}) => {
  console.log(`????  Server ready at ${url}`);
  console.log(`realtime here at ${subscriptionsUrl} and path ${subscriptionsPath}`)
});

What I'm doing wrong here, Is there anyone who came across with such issue?

Answer 1

You need to pass splited link to ApolloClient constructor. Try to pass it like this (client side):

import ApolloClient from 'apollo-boost';
import { WebSocketLink } from 'apollo-link-ws';
import { HttpLink } from 'apollo-link-http';
import { split } from 'apollo-link';
import { onError } from 'apollo-link-error';
import { getMainDefinition } from 'apollo-utilities';

const httpLink = new HttpLink({
  uri: 'http://localhost:4000/graphql'
});

export const wsLink = new WebSocketLink({
  uri: `ws://localhost:4000/subscriptions`,
  options: {
    reconnect: false
  }
});

export const link = split(
  // split based on operation type
  ({ query }) => {
    const definition = getMainDefinition(query);
    return (
      definition.kind === 'OperationDefinition' &&
      definition.operation === 'subscription'
    );
  },
  wsLink,
  httpLink,
);

export const graphqlServer = new ApolloClient({
    link: ApolloLink.from([
        onError(({
            graphQLErrors,
            networkError
        }) => {
            if (graphQLErrors) {
                graphQLErrors.map(({
                        message,
                        locations,
                        path
                    }) =>
                    console.log(
                        `[GraphQL error]: Message: ${message}, Location: ${locations}, Path: ${path}`
                    )
                );
            }
            if (networkError) {
                console.log(`[Network error]: ${networkError}`);
            }
        }),
        link // YOUR LINK (NOW MATCHING YOUR CODE)
    ])
});

And server side:

...
const server = new ApolloServer({ 
  typeDefs: schema, 
  resolvers: resolvers,
  subscriptions: {
        path: '/subscriptions'
  },
  context: {
    database
  }
});
...

Note that /subscriptions also passed to ApolloClient

Answer 2

I had to import ApolloClient from apollo-client. Here is the working configuration for client-side:

import ApolloClient from 'apollo-client';
import { WebSocketLink } from 'apollo-link-ws';
import { HttpLink } from 'apollo-link-http';
import { split } from 'apollo-link';
import { onError } from 'apollo-link-error';
import { InMemoryCache } from 'apollo-cache-inmemory';
import { getMainDefinition } from 'apollo-utilities';

export const httpLink = new HttpLink({
  uri: "http://localhost:4000/graphql", // use https for secure endpoint
});

// Create a WebSocket link:
export const wsLink = new WebSocketLink({
  uri: "ws://localhost:4000/subscriptions", // use wss for a secure endpoint
  options: {
    reconnect: true
  }
});

// using the ability to split links, you can send data to each link
// depending on what kind of operation is being sent
export const link = split(
  // split based on operation type
  ({ query }) => {
    const { kind, operation } = getMainDefinition(query);
    return kind === 'OperationDefinition' && operation === 'subscription';
  },
  wsLink,
  httpLink,
);

// Instantiate client
export const client = new ApolloClient({
  link,
  uri: "http://localhost:4000/graphql",
  cache: new InMemoryCache()
})