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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 { 
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: [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 run build

Then, run your backend with the following command:

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)
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