Adding basic routing support

src/server/request.ts

@@ -0,0 +1,35 @@
+import {RequestData} from 'next/dist/server/web/types';
+
+declare const nextConfig: RequestData['nextConfig'];
+
+// From https://developers.cloudflare.com/fundamentals/get-started/reference/http-request-headers/
+// and https://developers.cloudflare.com/workers/runtime-apis/request/#incomingrequestcfproperties
+export function getRequestData(request: Request): RequestData {
+	return {
+		url: request.url,
+		method: request.method,
+		headers: toPlainHeaders(request.headers),
+		ip: request.headers.get('CF-Connecting-IP') ?? undefined,
+		geo: {
+			country: request.cf?.country,
+			city: request.cf?.city,
+			region: request.cf?.region,
+			latitude: request.cf?.latitude,
+			longitude: request.cf?.longitude,
+		},
+		nextConfig,
+		// Should no longer be needed
+		page: undefined,
+		body: request.body,
+	};
+}
+
+function toPlainHeaders(headers: Headers): Record<string, string> {
+	const result: Record<string, string> = {};
+
+	for (const [value, key] of headers.entries()) {
+		result[key] = value;
+	}
+
+	return result;
+}

src/server/router.ts

@@ -0,0 +1,66 @@
+// The implementation depends deciphering the source code
+// of Next.js instead of following its document as there is none.
+// Should expect breakage during Next.js version change.
+
+import {RequestData} from 'next/dist/server/web/types';
+import {getRequestData} from './request';
+
+// eslint-disable-next-line @typescript-eslint/naming-convention
+declare const _ENTRIES: Record<
+	string,
+	{
+		default: (parameters: {
+			request: RequestData;
+		}) => Promise<{response: Response; waitUntil: Promise<any>}>;
+	}
+>;
+
+interface Route {
+	page: string;
+	regex: string;
+	routeKeys: Record<string, string>;
+	namedRegex: string;
+}
+
+declare const routesManifest: {
+	dynamicRoutes: Route[];
+};
+
+export const onRequest: PagesFunction = async ({
+	request,
+	waitUntil,
+	env: {ASSETS},
+}) => {
+	// For now we only support serve static then dynamic with no basepath or locale.
+	// https://nextjs.org/docs/advanced-features/middleware#matching-paths is the full route order we need to handle
+
+	const assetsResponse = await ASSETS.fetch(request);
+	if (assetsResponse.ok) {
+		return assetsResponse;
+	}
+
+	const url = new URL(request.url);
+
+	for (const route of routesManifest.dynamicRoutes) {
+		if (new RegExp(route.regex).test(url.pathname)) {
+			// eslint-disable-next-line no-await-in-loop
+			const {response, waitUntil: promise} = await _ENTRIES[
+				`middleware_${route.page}`
+			].default({request: getRequestData(request)});
+
+			waitUntil(promise);
+
+			return response;
+		}
+	}
+
+	const notFoundResponse = await ASSETS.fetch(
+		new URL('/404', request.url).toString(),
+	);
+
+	return new Response(notFoundResponse.body, {
+		...notFoundResponse,
+		status: 404,
+		statusText: 'Not found',
+	});
+};

tsconfig.json

@@ -12,7 +12,10 @@
     "esModuleInterop": true,
     "allowJs": true,
     "noEmit": true,
-    "resolveJsonModule": true
+    "resolveJsonModule": true,
+    "lib": [
+      "ES2020"
+    ]
   },
   "include": [
     "**/*.ts",