feat(dev): cloudflare dev server adapter

packages/waku/src/cli.ts

@@ -12,6 +12,7 @@ import type { Config } from './config.js';
 import { runner } from './lib/hono/runner.js';
 import { build } from './lib/builder/build.js';
 import { DIST_ENTRIES_JS, DIST_PUBLIC } from './lib/builder/constants.js';
+import type { FetchHandler } from './lib/hono/adapter.js';
 
 const require = createRequire(new URL('.', import.meta.url));
 
@@ -105,7 +106,15 @@ async function runDev() {
     return c.text('404 Not Found', 404);
   });
   const port = parseInt(values.port || '3000', 10);
-  await startServer(app, port);
+  let fetchHandler: FetchHandler | undefined;
+  if (values['with-cloudflare']) {
+    const { cloudflareDevServer } = await import(
+      './lib/hono/cloudflare-dev-server.js'
+    );
+    // @ts-expect-error wrangler dev server type is not included in Config
+    fetchHandler = cloudflareDevServer(app, config.wrangler);
+  }
+  await startServer({ ...app, fetch: fetchHandler || app.fetch } as Hono, port);
 }
 
 async function runBuild() {

packages/waku/src/lib/hono/adapter.ts

@@ -0,0 +1,8 @@
+import type { ExecutionContext, Hono } from 'hono';
+
+export type FetchAdapter = (app: Hono) => Promise<FetchHandler | undefined>;
+export type FetchHandler = (
+  req: Request,
+  env?: unknown,
+  executionCtx?: ExecutionContext,
+) => Promise<Response> | Response;

packages/waku/src/lib/hono/cloudflare-dev-server.ts

@@ -0,0 +1,36 @@
+/* eslint import/no-unresolved: 0 */
+import type { Hono } from 'hono';
+
+export const cloudflareDevServer = (app: Hono, cfOptions?: any) => {
+  try {
+    // @ts-expect-error: miniflare is a peer dependency (provided by miniflare)
+    const wsAssign = import('miniflare').then(({ WebSocketPair }) => {
+      Object.assign(globalThis, { WebSocketPair });
+    });
+
+    // @ts-expect-error: wrangler is a peer dependency
+    const proxy = import('wrangler').then(({ getPlatformProxy }) =>
+      getPlatformProxy({
+        ...(cfOptions || {}),
+      }).then((proxy: any) => {
+        return proxy;
+      }),
+    );
+
+    return async (req: Request) => {
+      await wsAssign;
+      const awaitedProxy = await proxy;
+      Object.assign(req, { cf: awaitedProxy.cf });
+      Object.assign(globalThis, {
+        caches: awaitedProxy.caches,
+      });
+      return app.fetch(req, awaitedProxy.env, awaitedProxy.ctx);
+    };
+  } catch (e) {
+    console.warn(
+      'Unable to set up Cloudflare dev server. Try installing wrangler to your dev dependencies.',
+      e,
+    );
+    return undefined;
+  }
+};