TransactionalConnection is not available in AppModule context

[Draykee]

Describe the bug
TransactionalConnection can't be injected into middleware.

UnknownDependenciesException [Error]: Nest can't resolve dependencies of the ShopApiMiddleware (ConfigService, SessionService, ?). Please make sure that the argument TransactionalConnection at index [2] is available in the AppModule context.


Potential solutions:
- If TransactionalConnection is a provider, is it part of the current AppModule?
- If TransactionalConnection is exported from a separate @Module, is that module imported within AppModule?
  @Module({
    imports: [ /* the Module containing TransactionalConnection */ ]
  })

To Reproduce
Steps to reproduce the behavior:

1. Create a class implementing NestMiddleware and inject TransactionalConnection in the contructor
2. Register the middleware and start the server

Expected behavior
TransactionalConnection should be available

Environment (please complete the following information):

• @vendure/core version: 1.3.0

Additional context
A comment on that topic in slack

I think I know why this happens. It is due to an internal refractor where I put TransactionalConnection in its own module which is not being directly imported by AppModule.

[michaelbromley]

2. Register the middleware and start the server

How exactly are you registering the middleware? Are you adding it to the apiOptions.middleware array, or something else?

I've tried to reproduce this using this middleware:

class MyMiddleware implements NestMiddleware {
    constructor(
        private connection: TransactionalConnection,
    ) {}
    use(req: any, res: any, next: any) {
        console.log('Request...');
        next();
    }
}

both by adding it to the middleware config array:

export const devConfig: VendureConfig = {
    apiOptions: {
        middleware: [{ handler: MyMiddleware, route: '/shop-api' }],
    },
}

and by registering it in a plugin:

@VendurePlugin({
    imports: [PluginCommonModule],
    providers: [],
})
class MyPlugin implements NestModule {
    configure(consumer: MiddlewareConsumer): any {
        consumer.apply(MyMiddleware).forRoutes('shop-api');
    }
}

export const devConfig: VendureConfig = {
    plugins: [MyPlugin],
}

and in both cases I cannot reproduce the error message you report. Could you provide a minimal reproduction?

[michaelbromley]

Update: I missed the @Injectable() decorator off my middleware, now I can reproduce 👍