refactor(core): extract the serve request handler into its own module (AI-assisted)

packages/docusaurus/src/commands/serve/requestHandler.ts

@@ -0,0 +1,74 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import serveHandler from 'serve-handler';
+import {applyTrailingSlash} from '@docusaurus/utils-common';
+import type http from 'node:http';
+import type {DocusaurusConfig} from '@docusaurus/types';
+
+type ServeRequestHandler = (
+  req: http.IncomingMessage,
+  res: http.ServerResponse,
+) => Promise<void>;
+
+export function createServeRequestHandler({
+  outDir,
+  baseUrl,
+  trailingSlash,
+}: {outDir: string} & Pick<
+  DocusaurusConfig,
+  'baseUrl' | 'trailingSlash'
+>): ServeRequestHandler {
+  return async (req, res) => {
+    // Automatically redirect requests to /baseUrl/
+    if (!req.url?.startsWith(baseUrl)) {
+      redirect(res, baseUrl);
+      return;
+    }
+
+    // We do the redirect ourselves for a good reason
+    // server-handler is annoying and won't include /baseUrl/ in redirects
+    // See https://github.com/meta/docusaurus/issues/10078#issuecomment-2084932934
+    if (baseUrl !== '/') {
+      // Not super robust, but should be good enough for our use case
+      // See https://github.com/meta/docusaurus/pull/10090
+      const looksLikeAsset = !!req.url.match(/\.[a-z\d]{1,4}$/i);
+      if (!looksLikeAsset) {
+        const normalizedUrl = applyTrailingSlash(req.url, {
+          trailingSlash,
+          baseUrl,
+        });
+        if (req.url !== normalizedUrl) {
+          redirect(res, normalizedUrl);
+          return;
+        }
+      }
+    }
+
+    // Remove baseUrl before calling serveHandler, because /baseUrl/ should
+    // serve /build/index.html, not /build/baseUrl/index.html (does not exist)
+    // Note server-handler is really annoying here:
+    // - no easy way to do rewrites such as "/baseUrl/:path" => "/:path"
+    // - no easy way to "reapply" the baseUrl to the redirect "Location" header
+    // See also https://github.com/meta/docusaurus/pull/10090
+    req.url = req.url.replace(baseUrl, '/');
+
+    await serveHandler(req, res, {
+      cleanUrls: true,
+      public: outDir,
+      trailingSlash,
+      directoryListing: false,
+    });
+  };
+}
+
+function redirect(res: http.ServerResponse, location: string) {
+  res.writeHead(302, {
+    Location: location,
+  });
+  res.end();
+}

packages/docusaurus/src/commands/serve/serve.ts

@@ -9,23 +9,15 @@ import http from 'node:http';
 import path from 'node:path';
 import logger from '@docusaurus/logger';
 import {DEFAULT_BUILD_DIR_NAME} from '@docusaurus/utils';
-import serveHandler from 'serve-handler';
-import {applyTrailingSlash} from '@docusaurus/utils-common';
 import {realpath} from '@docusaurus/fs';
 import openBrowser from '../utils/openBrowser/openBrowser';
 import {loadSiteConfig} from '../../server/config';
 import {build} from '../build/build';
 import {getHostPort, type HostPortOptions} from '../../server/getHostPort';
 import {listenToServer} from './listenToServer';
+import {createServeRequestHandler} from './requestHandler';
 import type {LoadContextParams} from '../../server/site';
 
-function redirect(res: http.ServerResponse, location: string) {
-  res.writeHead(302, {
-    Location: location,
-  });
-  res.end();
-}
-
 export type ServeCLIOptions = HostPortOptions &
   Pick<LoadContextParams, 'config'> & {
     dir?: string;
@@ -64,47 +56,9 @@ export async function serve(
 
   const servingUrl = `http://${host}:${port}`;
 
-  const server = http.createServer((req, res) => {
-    // Automatically redirect requests to /baseUrl/
-    if (!req.url?.startsWith(baseUrl)) {
-      redirect(res, baseUrl);
-      return;
-    }
-
-    // We do the redirect ourselves for a good reason
-    // server-handler is annoying and won't include /baseUrl/ in redirects
-    // See https://github.com/meta/docusaurus/issues/10078#issuecomment-2084932934
-    if (baseUrl !== '/') {
-      // Not super robust, but should be good enough for our use case
-      // See https://github.com/meta/docusaurus/pull/10090
-      const looksLikeAsset = !!req.url.match(/\.[a-z\d]{1,4}$/i);
-      if (!looksLikeAsset) {
-        const normalizedUrl = applyTrailingSlash(req.url, {
-          trailingSlash,
-          baseUrl,
-        });
-        if (req.url !== normalizedUrl) {
-          redirect(res, normalizedUrl);
-          return;
-        }
-      }
-    }
-
-    // Remove baseUrl before calling serveHandler, because /baseUrl/ should
-    // serve /build/index.html, not /build/baseUrl/index.html (does not exist)
-    // Note server-handler is really annoying here:
-    // - no easy way to do rewrites such as "/baseUrl/:path" => "/:path"
-    // - no easy way to "reapply" the baseUrl to the redirect "Location" header
-    // See also https://github.com/meta/docusaurus/pull/10090
-    req.url = req.url.replace(baseUrl, '/');
-
-    serveHandler(req, res, {
-      cleanUrls: true,
-      public: outDir,
-      trailingSlash,
-      directoryListing: false,
-    });
-  });
+  const server = http.createServer(
+    createServeRequestHandler({outDir, baseUrl, trailingSlash}),
+  );
 
   const url = servingUrl + baseUrl;
   logger.success`Serving path=${buildDir} directory at: url=${url}`;