Example: Access Logged-In User

This document gives an example of how you can use middlewares to register the logged-in user in the dependency container of your commerce application. You can then access the logged-in user in other resources, such as services.

Tip

You can apply the same steps if you want to register the current customer.

Learn more about middlewares in its guide.

Step 1: Create the Middleware

Create the file src/api/middlewares.ts with the following content:

src/api/middlewares.ts

import type { 
  authenticate,
  MiddlewaresConfig, 
  User, 
  UserService,
} from "@medusajs/medusa"
import type { 
  MedusaNextFunction, 
  MedusaRequest, 
  MedusaResponse,
} from "@medusajs/medusa"

const registerLoggedInUser = async (
  req: MedusaRequest, 
  res: MedusaResponse, 
  next: MedusaNextFunction
) => {
  let loggedInUser: User | null = null

  if (req.user && req.user.userId) {
    const userService = 
      req.scope.resolve("userService") as UserService
    loggedInUser = await userService.retrieve(req.user.userId)
  }

  req.scope.register({
    loggedInUser: {
      resolve: () => loggedInUser,
     },
   })
  
  next()
}

export const config: MiddlewaresConfig = {
  routes: [
    {
      matcher: "/admin/products",
      middlewares: [authenticate(), registerLoggedInUser],
    },
  ],
}

This creates a registerLoggedInUser middleware that handles registering the logged-in user in the dependency container.

It then applies this middleware on the /admin/products API Route. You can change that to be the route of any other API Route or a pattern that matches multiple routes.

---

Step 2: Use in a Service

Access the logged-in user resource in the constructor of a service:

import { Lifetime } from "awilix"
import { 
  TransactionBaseService, 
  User,
} from "@medusajs/medusa"

class HelloService extends TransactionBaseService {

  protected readonly loggedInUser_: User | null

  constructor(container, options) {
    super(...arguments)

    try {
      this.loggedInUser_ = container.loggedInUser
    } catch (e) {
      // avoid errors when backend first runs
    }
  }

  // ...
}

export default HelloService

If you're accessing it in an extended core service, it’s important to change the lifetime of the service to Lifetime.SCOPED. For example:

import { Lifetime } from "awilix"
import { 
  ProductService as MedusaProductService, 
  User, 
} from "@medusajs/medusa"

// extend core product service
class ProductService extends MedusaProductService {
  // The default life time for a core service is SINGLETON
  static LIFE_TIME = Lifetime.SCOPED

  protected readonly loggedInUser_: User | null

  constructor(container, options) {
    super(...arguments)

    this.loggedInUser_ = container.loggedInUser
  }
}

export default ProductService

You can learn more about the importance of changing the service lifetime in the Middlewares documentation.

---

Step 3: Test it Out

To test out your implementation, run the following command in the root directory of the Medusa backend to transpile your changes:

• npm
• Yarn
• pnpm

npm run build

yarn build

pnpm run build

Then, run your backend with the following command:

• npm
• Yarn
• pnpm

npx medusa develop

npx medusa develop

npx medusa develop

If you try accessing the API Routes you added the middleware to, you should see your implementation working as expected.

---

Troubleshooting

AwilixResolutionError: Could Not Resolve X

AwilixResolutionError: Could Not Resolve X (Custom Registration)