[SOLVED] NestJS GraphQL subscriptions not working with `graphql-ws`

NestJS GraphQL subscriptions not working with `graphql-ws`

I'm trying to upgrade our NestJS GraphQL subscriptions server to utilize graphql-ws rather than the current subscriptions-transport-ws (as suggested by the NestJS documentation). I upgraded the NestJS version to

    "@nestjs/core": "^8.0.6",
    "@nestjs/graphql": "^9.0.4",
    "@nestjs/platform-express": "^8.0.6",
    "graphql": "^15.5.3",
    "graphql-tools": "^8.2.0",
    "apollo-server-express": "^3.3.0",

And after, I added the subscriptions option to the App.Module:

    GraphQLModule.forRoot({
      autoSchemaFile: true,
      sortSchema: true,
      playground: true,
      installSubscriptionHandlers: true,
      subscriptions: {
        'graphql-ws': true
      },
    }),

However when I subscribe (in playground) to a previously working subscription, I get:

{
  "error": "Could not connect to websocket endpoint ws://localhost:8880/graphql. Please check if the endpoint url is correct."
}

And in the console I get:

WebSocket protocol error occured. It was most likely caused due to an unsupported subprotocol "graphql-ws" requested by the client. graphql-ws implements exclusively the "graphql-transport-ws" subprotocol, please make sure that the client implements it too.

Things I have tried:

Adding the graphql-ws package
Upgrading the NestJS version again
Removing the installSubscriptionHandlers option from config
Setting graphql-ws configs instead of passing true
Using the WebSocket Test Client Google Chrome extension instead of Playground

But none have worked. Sorry for the long post. How can I fix this?

Solution

At the time of release of Apollo Server 3, the protocol used in the graphql-ws library is not yet supported by GraphQL Playground or Apollo Explorer.

see here

It's only advisable to use graphql-ws if interacting with subscriptions via playground is not of much use to you and you're okay interacting with subscriptions solely from your own client that has been setup to use graphql-ws.

To setup your client to use graphql-ws with Apollo. see here.