feat(medusa,dashboard,admin-sdk): Run admin dashboard from Medusa instance (#7330)

packages/admin-next/admin-sdk/src/lib/serve.ts

@@ -0,0 +1,53 @@
+import { Request, Response, Router, static as static_ } from "express"
+import fs from "fs"
+import { ServerResponse } from "http"
+import path from "path"
+
+type ServeOptions = {
+  outDir: string
+}
+
+const router = Router()
+
+export async function serve(options: ServeOptions) {
+  const htmlPath = path.resolve(options.outDir, "index.html")
+
+  /**
+   * The admin UI should always be built at this point, but in the
+   * rare case that another plugin terminated a previous startup, the admin
+   * may not have been built correctly. Here we check if the admin UI
+   * build files exist, and if not, we throw an error, providing the
+   * user with instructions on how to fix their build.
+   */
+
+  const indexExists = fs.existsSync(htmlPath)
+
+  if (!indexExists) {
+    throw new Error(
+      `Could not find the admin UI build files. Please run "medusa-admin build" or enable "autoRebuild" in the plugin options to build the admin UI.`
+    )
+  }
+
+  const html = fs.readFileSync(htmlPath, "utf-8")
+
+  const sendHtml = (_req: Request, res: Response) => {
+    res.setHeader("Cache-Control", "no-cache")
+    res.setHeader("Vary", "Origin, Cache-Control")
+    res.send(html)
+  }
+
+  const setStaticHeaders = (res: ServerResponse) => {
+    res.setHeader("Cache-Control", "max-age=31536000, immutable")
+    res.setHeader("Vary", "Origin, Cache-Control")
+  }
+
+  router.get("/", sendHtml)
+  router.use(
+    static_(options.outDir, {
+      setHeaders: setStaticHeaders,
+    })
+  )
+  router.get(`/*`, sendHtml)
+
+  return router
+}