GraphQL subscriptions and Request context

[pphunor72]

I use NestJS-GraphQL-MikroORM frameworks to build my backend and I have problem using graphql subscriptions (graphql-ws based). I do not find the point where and how the proper context initialization should be done.

I have a scheduled task (with @UseRequestContext() decorator as described in documentation) where I build a list of entities and I publish them. Until this point everything seems to be fine.
The problem comes when these entities have properties which are resolved later by @ResolveField decorators. Resolving these properties generates further ORM queries, but they are already out of that scope. They try to use the global entity manager which fails by design.

I did not find such entry point like express middlewares to perform the context initialization. It is just a simple context() function call where I can add extra data to the context, but the scope goes away when I return, so the AsyncLocalStorage based RequestContext cannot be used here.

How can keep my entity repositories operational in this case? I do not want to check (and fork if necessary) the entity manager in every ORM request.

[Morb0]

Did you manage to solve the problem?

[pphunor72]

Not really, I had to modify the entity to avoid using ResolveField.

[Morb0]

Ouch. I think workground here can be saving entity manager fork to apollo context, like this:
https://github.com/driescroons/mikro-orm-graphql-example/blob/master/src/application.ts#L61-L67
And using this entity manager in ResolveField.