feat(medusa): Middleware to add default SC on query if no SC already exist on it (#3694)

packages/medusa/src/api/middlewares/with-default-sales-channel.ts

@@ -0,0 +1,45 @@
+import { NextFunction, Request, Response } from "express"
+import SalesChannelFeatureFlag from "../../loaders/feature-flags/sales-channels"
+import { SalesChannelService } from "../../services"
+import { FlagRouter } from "../../utils/flag-router"
+
+/**
+ * Middleware that includes the default sales channel on the request, if no sales channels present
+ * @param context Object of options
+ * @param context.attachChannelAsArray Whether to attach the default sales channel as an array or just a string
+ */
+export function withDefaultSalesChannel({
+  attachChannelAsArray,
+}: {
+  attachChannelAsArray?: boolean
+}): (req: Request, res: Response, next: NextFunction) => Promise<void> {
+  return async (req: Request, _, next: NextFunction) => {
+    const featureFlagRouter = req.scope.resolve(
+      "featureFlagRouter"
+    ) as FlagRouter
+
+    if (
+      !featureFlagRouter.isFeatureEnabled(SalesChannelFeatureFlag.key) ||
+      req.query.sales_channel_id?.length ||
+      req.get("x-publishable-api-key")
+    ) {
+      return next()
+    }
+
+    const salesChannelService: SalesChannelService = req.scope.resolve(
+      "salesChannelService"
+    )
+
+    try {
+      const defaultSalesChannel = await salesChannelService.retrieveDefault()
+      if (defaultSalesChannel?.id) {
+        req.query.sales_channel_id = attachChannelAsArray
+          ? [defaultSalesChannel.id]
+          : defaultSalesChannel.id
+      }
+    } catch {
+    } finally {
+      next()
+    }
+  }
+}

packages/medusa/src/api/routes/store/products/index.ts

@@ -12,6 +12,7 @@ import { StoreGetProductsProductParams } from "./get-product"
 import { extendRequestParams } from "../../../middlewares/publishable-api-key/extend-request-params"
 import { validateProductSalesChannelAssociation } from "../../../middlewares/publishable-api-key/validate-product-sales-channel-association"
 import { validateSalesChannelParam } from "../../../middlewares/publishable-api-key/validate-sales-channel-param"
+import { withDefaultSalesChannel } from "../../../middlewares/with-default-sales-channel"
 
 const route = Router()
 
@@ -26,6 +27,7 @@ export default (app, featureFlagRouter: FlagRouter) => {
 
   route.get(
     "/",
+    withDefaultSalesChannel({ attachChannelAsArray: true }),
     transformStoreQuery(StoreGetProductsParams, {
       defaultRelations: defaultStoreProductsRelations,
       defaultFields: defaultStoreProductsFields,
@@ -38,6 +40,7 @@ export default (app, featureFlagRouter: FlagRouter) => {
 
   route.get(
     "/:id",
+    withDefaultSalesChannel({}),
     transformStoreQuery(StoreGetProductsProductParams, {
       defaultRelations: defaultStoreProductsRelations,
       defaultFields: defaultStoreProductsFields,