feat: add middleware-file-loader (#11638)

Fixes: FRMW-2920

The feature is called `middleware-file-loader`, because it does more than just collecting middlewares. It also collects the bodyParser config for routes

.changeset/grumpy-pumas-occur.md

@@ -0,0 +1,5 @@
+---
+"@medusajs/framework": patch
+---
+
+feat: add middleware-file-loader

packages/core/framework/src/http/__fixtures__/routers-middleware/middlewares.ts

@@ -43,6 +43,12 @@ export default defineMiddlewares([
     matcher: "/store/*",
     middlewares: [storeGlobal],
   },
+  {
+    matcher: "/webhooks",
+    bodyParser: {
+      preserveRawBody: true,
+    },
+  },
   {
     matcher: "/webhooks/*",
     method: "POST",

packages/core/framework/src/http/__tests__/middleware-file-loader.spec.ts

@@ -0,0 +1,51 @@
+import { resolve } from "path"
+import { MiddlewareFileLoader } from "../middleware-file-loader"
+
+describe("Middleware file loader", () => {
+  it("should load routes from the filesystem", async () => {
+    const BASE_DIR = resolve(__dirname, "../__fixtures__/routers-middleware")
+    const loader = new MiddlewareFileLoader({})
+    await loader.scanDir(BASE_DIR)
+
+    expect(loader.getBodyParserConfigRoutes()).toMatchInlineSnapshot(`
+      [
+        {
+          "config": {
+            "preserveRawBody": true,
+          },
+          "matcher": "/webhooks",
+          "method": undefined,
+        },
+        {
+          "config": false,
+          "matcher": "/webhooks/*",
+          "method": "POST",
+        },
+      ]
+    `)
+    expect(loader.getMiddlewares()).toMatchInlineSnapshot(`
+      [
+        {
+          "handler": [Function],
+          "matcher": "/customers",
+          "method": undefined,
+        },
+        {
+          "handler": [Function],
+          "matcher": "/customers",
+          "method": "POST",
+        },
+        {
+          "handler": [Function],
+          "matcher": "/store/*",
+          "method": undefined,
+        },
+        {
+          "handler": [Function],
+          "matcher": "/webhooks/*",
+          "method": "POST",
+        },
+      ]
+    `)
+  })
+})

packages/core/framework/src/http/middleware-file-loader.ts

@@ -0,0 +1,154 @@
+import { join } from "path"
+import { dynamicImport, FileSystem } from "@medusajs/utils"
+
+import { logger } from "../logger"
+import type {
+  MiddlewaresConfig,
+  BodyParserConfigRoute,
+  ScannedMiddlewareDescriptor,
+} from "./types"
+
+/**
+ * File name that is used to indicate that the file is a middleware file
+ */
+const MIDDLEWARE_FILE_NAME = "middlewares"
+
+const log = ({
+  activityId,
+  message,
+}: {
+  activityId?: string
+  message: string
+}) => {
+  if (activityId) {
+    logger.progress(activityId, message)
+    return
+  }
+
+  logger.debug(message)
+}
+
+/**
+ * Exposes the API to scan a directory and load the `middleware.ts` file. This file contains
+ * the configuration for certain global middlewares and core routes validators. Also, it may
+ * contain custom middlewares.
+ */
+export class MiddlewareFileLoader {
+  /**
+   * Middleware collected manually or by scanning directories
+   */
+  #middleware: ScannedMiddlewareDescriptor[] = []
+  #bodyParserConfigRoutes: BodyParserConfigRoute[] = []
+
+  /**
+   * An eventual activity id for information tracking
+   */
+  readonly #activityId?: string
+
+  constructor({ activityId }: { activityId?: string }) {
+    this.#activityId = activityId
+  }
+
+  /**
+   * Processes the middleware file and returns the middleware and the
+   * routes config exported by it.
+   */
+  async #processMiddlewareFile(absolutePath: string): Promise<void> {
+    const middlewareExports = await dynamicImport(absolutePath)
+
+    const middlewareConfig = middlewareExports.default
+    if (!middlewareConfig) {
+      log({
+        activityId: this.#activityId,
+        message: `No middleware configuration found in ${absolutePath}. Skipping middleware configuration.`,
+      })
+      return
+    }
+
+    const routes = middlewareConfig.routes as MiddlewaresConfig["routes"]
+    if (!routes || !Array.isArray(routes)) {
+      log({
+        activityId: this.#activityId,
+        message: `Invalid default export found in ${absolutePath}. Make sure to use "defineMiddlewares" function and export its output.`,
+      })
+      return
+    }
+
+    const result = routes.reduce<{
+      bodyParserConfigRoutes: BodyParserConfigRoute[]
+      middleware: ScannedMiddlewareDescriptor[]
+    }>(
+      (result, route) => {
+        if (!route.matcher) {
+          throw new Error(
+            `Middleware is missing a \`matcher\` field. The 'matcher' field is required when applying middleware. ${JSON.stringify(
+              route,
+              null,
+              2
+            )}`
+          )
+        }
+
+        const matcher = String(route.matcher)
+
+        if ("bodyParser" in route && route.bodyParser !== undefined) {
+          result.bodyParserConfigRoutes.push({
+            matcher: matcher,
+            method: route.method,
+            config: route.bodyParser,
+          })
+        }
+
+        if (route.middlewares) {
+          route.middlewares.forEach((middleware) => {
+            result.middleware.push({
+              handler: middleware,
+              matcher: matcher,
+              method: route.method,
+            })
+          })
+        }
+        return result
+      },
+      {
+        bodyParserConfigRoutes: [],
+        middleware: [],
+      }
+    )
+
+    this.#middleware = result.middleware
+    this.#bodyParserConfigRoutes = result.bodyParserConfigRoutes
+  }
+
+  /**
+   * Scans a given directory for the "middleware.ts" or "middleware.js" files and
+   * imports them for reading the registered middleware and configuration for
+   * existing routes/middleware.
+   */
+  async scanDir(sourceDir: string) {
+    const fs = new FileSystem(sourceDir)
+    if (await fs.exists(`${MIDDLEWARE_FILE_NAME}.ts`)) {
+      await this.#processMiddlewareFile(
+        join(sourceDir, `${MIDDLEWARE_FILE_NAME}.ts`)
+      )
+    } else if (await fs.exists(`${MIDDLEWARE_FILE_NAME}.js`)) {
+      await this.#processMiddlewareFile(
+        join(sourceDir, `${MIDDLEWARE_FILE_NAME}.ts`)
+      )
+    }
+  }
+
+  /**
+   * Returns a collection of registered middleware
+   */
+  getMiddlewares() {
+    return this.#middleware
+  }
+
+  /**
+   * Returns routes that have bodyparser config on them
+   */
+  getBodyParserConfigRoutes() {
+    return this.#bodyParserConfigRoutes
+  }
+}

packages/core/framework/src/http/routes-sorter.ts

@@ -25,7 +25,7 @@ type Route = {
   /**
    * The HTTP methods this route is supposed to handle.
    */
-  methods?: MiddlewareVerb[]
+  methods?: MiddlewareVerb | MiddlewareVerb[]
 }
 
 /**
@@ -108,7 +108,6 @@ export class RoutesSorter {
 
   constructor(routes: Route[]) {
     this.#routesToProcess = routes
-    console.log("Processing routes", this.#routesToProcess)
   }
 
   /**

packages/core/framework/src/http/types.ts

@@ -111,6 +111,18 @@ export type FileSystemRouteDescriptor = ScannedRouteDescriptor & {
   relativePath: string
 }
 
+export type ScannedMiddlewareDescriptor = {
+  matcher: string
+  method?: MiddlewareVerb | MiddlewareVerb[]
+  handler: MiddlewareFunction
+}
+
+export type BodyParserConfigRoute = {
+  matcher: string
+  method?: MiddlewareVerb | MiddlewareVerb[]
+  config?: ParserConfig
+}
+
 export type GlobalMiddlewareDescriptor = {
   config?: MiddlewaresConfig
 }