middleware.ts — astro Source File

Source Code

import { existsSync } from 'node:fs';
import { builtinModules } from 'node:module';
import { fileURLToPath, pathToFileURL } from 'node:url';
import type { AstroIntegrationLogger } from 'astro';
import {
	ASTRO_LOCALS_HEADER,
	ASTRO_MIDDLEWARE_SECRET_HEADER,
	ASTRO_PATH_HEADER,
	NODE_PATH,
} from '../index.js';

/**
 * It generates the Vercel Edge Middleware file.
 *
 * It creates a temporary file, the edge middleware, with some dynamic info.
 *
 * Then this file gets bundled with esbuild. The bundle phase will inline the Astro middleware code.
 *
 * @param astroMiddlewareEntryPointPath
 * @param root
 * @param vercelEdgeMiddlewareHandlerPath
 * @param outPath
 * @param middlewareSecret
 * @param logger
 * @returns {Promise<URL>} The path to the bundled file
 */
export async function generateEdgeMiddleware(
	astroMiddlewareEntryPointPath: URL,
	root: URL,
	vercelEdgeMiddlewareHandlerPath: URL,
	outPath: URL,
	middlewareSecret: string,
	logger: AstroIntegrationLogger,
): Promise<URL> {
	const code = edgeMiddlewareTemplate(
		astroMiddlewareEntryPointPath,
		vercelEdgeMiddlewareHandlerPath,
		middlewareSecret,
		logger,
	);
	// https://vercel.com/docs/concepts/functions/edge-middleware#create-edge-middleware
	const bundledFilePath = fileURLToPath(outPath);
	const esbuild = await import('esbuild');
	try {
		await esbuild.build({
			stdin: {
				contents: code,
				resolveDir: fileURLToPath(root),
			},
			// Vercel Edge runtime targets ESNext, because Cloudflare Workers update v8 weekly
			// https://github.com/vercel/vercel/blob/1006f2ae9d67ea4b3cbb1073e79d14d063d42436/packages/next/scripts/build-edge-function-template.js
			target: 'esnext',
			platform: 'browser',
			// esbuild automatically adds the browser, import and default conditions
			// https://esbuild.github.io/api/#conditions
			// https://runtime-keys.proposal.wintercg.org/#edge-light
			conditions: ['edge-light', 'workerd', 'worker'],
			outfile: bundledFilePath,
			allowOverwrite: true,
			format: 'esm',
// ... (91 more lines)