Store custom extra data on the context object

[idevelop]

Apologies if I missed this in the documentation, just wondering how I would go about storing some specific extra data in the context.extra field? As far as I can tell, that field is typed as only storing the objects that result from the server initialisation (websocket, http request, etc), and there doesn't seem to be a way for me to extend that Extra type when creating the server.

My use case is: in the onConnect callback, after validating the auth token the client provides in connectionParams, I'd like to create a Session object (containing userID, some user-specific objects, etc), that then becomes available to the resolvers.

As I understand from the documentation, the context callback is called on every operation so it's not really suitable for this, since ideally I'd like to not re-validate the auth token and recreate the Session object on every single operation, since it would be very wasteful. So my next thought was to store that Session object in the context.extra object, but that doesn't seem to be possible.

Thanks!

[idevelop]

This seems to work but needs some @ts-ignore comments:

makeBehavior({
  onConnect: async (ctx) => {
    // @ts-ignore
    ctx.extra.context = await authenticatedRequestContext(ctx.connectionParams);
    return true;
  },
  // @ts-ignore
  context: (ctx) => ctx.extra.context,
})

[enisdenjo]

The context extra is meant to be created when opening connections, this is why you are able to set the generic through makeServer and provide the extra through the opened method used for implementing your own WS server. You're absolutely free to implement your own server and use the makeServer with the most relevant context extras for you.

However, the context extras are meant to be used by the user; meaning, you're free to assign whatever and whenever you want to ctx.extra (exactly how you did in #189 (comment)).

But, you're indeed right about it not being typed and how strenuous that might be. Maybe provide an extra generic for both ws.useServer and uws.makeBehaviour that extends the context extra typings and allows you to have a type safe extra object?

Furthermore, just wanted to point out an important distinction: the ctx argument is the WebSocket connection context and the context option is the GraphQL contextValue.

[idevelop]

Maybe provide an extra generic for both ws.useServer and uws.makeBehaviour that extends the context extra typings and allows you to have a type safe extra object?

Thanks for clarifying, that would be nice yeah!

Something like

export declare function makeBehavior<T = {}>(options: ServerOptions<Extra & Partial<T>>, ...);

makeBehavior<{ session: Session }>(...)

The Partial is there to allow for the user-provided Extra fields to be undefined between the connection being established and when onConnect has had a chance to populate them with real values.

[enisdenjo]

Makes sense! Lets see what I can do.

[enisdenjo]

🎉 This issue has been resolved in version 4.6.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀