From 9f0fea0ad7ef90325c9ff3d2bcc6cfe77c37515d Mon Sep 17 00:00:00 2001
From: Tom Everson <96673241+TomEverson@users.noreply.github.com>
Date: Tue, 13 Dec 2022 17:05:21 +0630
Subject: [PATCH] Add Vercel middleware docs to Vercel integration README
 (#5576)

Co-authored-by: Chris Swithinbank <swithinbank@gmail.com>
---
 packages/integrations/vercel/README.md | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/packages/integrations/vercel/README.md b/packages/integrations/vercel/README.md
index a5cbce5ca70b..2948e8b0f02b 100644
--- a/packages/integrations/vercel/README.md
+++ b/packages/integrations/vercel/README.md
@@ -129,6 +129,30 @@ export default defineConfig({
 });
 ```
 
+### Vercel Middleware
+
+You can use Vercel middleware to intercept a request and redirect before sending a response. Vercel middleware can run for Edge, SSR, and Static deployments. You don't need to install `@vercel/edge` to write middleware, but you do need to install it to use features such as geolocation. For more information see [Vercel’s middleware documentation](https://vercel.com/docs/concepts/functions/edge-middleware).
+
+1. Add a `middleware.js` file to the root of your project:
+
+    ```js
+    // middleware.js
+    export const config = {
+      // Only run the middleware on the admin route
+      matcher: '/admin',
+    };
+
+    export default function middleware(request) {
+      const url = new URL(request.url);
+      // You can retrieve IP location or cookies here.
+      if (url.pathname === "/admin") {
+        url.pathname = "/"
+      }
+      return Response.redirect(url);
+    }
+    ```
+1. While developing locally, you can run `vercel dev` to run middleware. In production, Vercel will handle this for you.
+
 ## Troubleshooting
 
 **A few known complex packages (example: [puppeteer](https://github.com/puppeteer/puppeteer)) do not support bundling and therefore will not work properly with this adapter.** By default, Vercel doesn't include npm installed files & packages from your project's `./node_modules` folder. To address this, the `@astrojs/vercel` adapter automatically bundles your final build output using `esbuild`.