## Add request injection token

### Set reference to request object

```typescript
application.use((req, res, next) => {
  // Create context ...

  // attach the request to the context so you can refernce it later on
  context.setExtra("request", req);

  // rest of code
});
```

### Create _InjectionToken_

`request_token.ts` file

```typescript
import { Request } from "express";
export const REQUEST_TOKEN = new InjectionToken<Request>("TOKEN_REQUEST", {
  lifetime: ServiceLifetime.Scoped,
  implementationFactory: (context) => context.getExtra("request"),
});
```

### Use `@Inject` to reference `REQUEST_TOKEN`

```typescript
@Injectable({
  lifetime: ServiceLifetime.Scoped,
})
export class DataService {
  constructor(@Inject(REQUEST_TOKEN) private request: Request) {
    const userAgent = request.headers["user-agent"];
  }
}
```

---

Make sure that the service that utilize the `REQUEST_TOKEN` is

1. Either `Transient` or `Scoped`.
2. Descendant of `Scoped` controller