Subscriptions - context not extended

Hey,

we have upgraded to apollo server 2 and now have trouble with the GraphQL context in the subscription resolvers. We have an ApolloServer and will extend the GraphQL context with some data the client sent during the first connect. In the docs is an example.

We’ve implemeted the onConnect and return some data:

...
subscriptions: {
  onConnect: (connectionParams: ConnectionParams) => {
    // do sth. with the connection params
    return { some: 'data' };
  }
}
...

The documentation says the return value of the onConnect function extends the GraphQL context. The onConnect gets executed when a new client connects.

In our resolver we want to do some filtering based on the extended context:

...
subscribe: withFilter(
  () => this.pubSub.subscribe('xxx'),
  (payload, _, ctx: IGraphQLContext) => {
    // do sth. with `ctx.some`
    return true;
  },
),

But the context in the resolver is always empty.

We are on the latest version of apollo-server-express and subscriptions-transport-ws.

Thank you very much for your help!

[marcel-devdude]

The return value of the onConnect callback is available in the context function. So you can return it if you build the context for subscriptions.

...
subscriptions: {
  onConnect: async (connectionParams) => {
    // Do some stuff with connectionParams like auth
    
    return { extended: 'context' };
  },
},
context: async ({ req, connection }) => {
  // If we build the context for subscriptions, return the context generated in the onConnect callback.
  // In this example `connection.context` is `{ extended: 'context' }`
  if (!req || !req.headers) {
    return connection.context;
  }

  // Build context for normal requests
  return { regular: 'context' };
},
...

[glasser]

Apollo Server v3 does not have built-in support for subscriptions (we felt that the superficial integration with the unmaintained subscriptions-transport-ws package was not up to our standards). https://www.apollographql.com/docs/apollo-server/data/subscriptions/ documents how to integrate Apollo Server with the newer graphql-ws package, including a whole section on the context value. There’s a link at the bottom to the previous version of the docs which explains how to integrate AS with the unmaintained subscriptions-transport-ws package too if you need to.