[cli][dev][node] Support matchers config for Middleware in vc dev (#8033)

Adds support for `config.matchers` exported property in Middleware during `vc dev`.

packages/cli/src/util/dev/server.ts

@@ -1430,6 +1430,7 @@ export default class DevServer {
             meta: {
               isDev: true,
               devCacheDir,
+              requestUrl: req.url,
               env: { ...envConfigs.runEnv },
               buildEnv: { ...envConfigs.buildEnv },
             },

packages/cli/test/dev/fixtures/middleware-matchers/middleware.js

@@ -0,0 +1,13 @@
+// Supports both a single string value or an array of matchers
+export const config = {
+  matcher: ['/about/:path*', '/dashboard/:path*'],
+};
+
+export default function middleware(request, _event) {
+  const response = new Response('middleware response');
+
+  // Set custom header
+  response.headers.set('x-modified-edge', 'true');
+
+  return response;
+}

packages/cli/test/dev/integration-4.test.ts

@@ -505,3 +505,21 @@ test(
     await testPath(500, '/', /EDGE_FUNCTION_INVOCATION_FAILED/);
   })
 );
+
+test(
+  '[vercel dev] Middleware with `matchers` config',
+  testFixtureStdio(
+    'middleware-matchers',
+    async (testPath: any) => {
+      // TODO: remove once latest `@vercel/node` is shipped to stable with `matchers` support (fails because `directoryListing`)
+      //await testPath(404, '/');
+      await testPath(404, '/another');
+      await testPath(200, '/about/page', 'middleware response');
+      await testPath(200, '/dashboard/home', 'middleware response');
+    },
+    {
+      // TODO: remove once latest `@vercel/node` is shipped to stable with `matchers` support
+      skipDeploy: true,
+    }
+  )
+);

packages/node/src/index.ts

@@ -460,7 +460,26 @@ export const prepareCache: PrepareCache = ({ repoRootPath, workPath }) => {
 
 export const startDevServer: StartDevServer = async opts => {
   const { entrypoint, workPath, config, meta = {} } = opts;
-  const entryDir = join(workPath, dirname(entrypoint));
+  const entrypointPath = join(workPath, entrypoint);
+
+  if (config.middleware === true && typeof meta.requestUrl === 'string') {
+    // TODO: static config is also parsed in `dev-server.ts`.
+    // we should pass in this version as an env var instead.
+    const project = new Project();
+    const staticConfig = getConfig(project, entrypointPath);
+
+    // Middleware is a catch-all for all paths unless a `matcher` property is defined
+    const matchers = new RegExp(getRegExpFromMatchers(staticConfig?.matcher));
+
+    if (!matchers.test(meta.requestUrl)) {
+      // If the "matchers" doesn't say to handle this
+      // path then skip middleware invocation
+      return null;
+    }
+  }
+
+  const entryDir = dirname(entrypointPath);
+
   const projectTsConfig = await walkParentDirs({
     base: workPath,
     start: entryDir,