feat(@astrojs/netlify): edge middleware support (#7632)

Co-authored-by: Bjorn Lu <bjornlu.dev@gmail.com>
Co-authored-by: Yan Thomas <61414485+Yan-Thomas@users.noreply.github.com>

1 files changed, 75 insertions, 0 deletions

diff --git a/packages/integrations/netlify/src/middleware.ts b/packages/integrations/netlify/src/middleware.ts
new file mode 100644
index 000000000..a53d4fbde
--- /dev/null
+++ b/packages/integrations/netlify/src/middleware.ts
@@ -0,0 +1,75 @@
+import { fileURLToPath, pathToFileURL } from 'node:url';
+import { join } from 'node:path';
+import { existsSync } from 'node:fs';
+import { ASTRO_LOCALS_HEADER } from './integration-functions.js';
+import { DENO_SHIM } from './shared.js';
+
+/**
+ * It generates a Netlify edge function.
+ *
+ */
+export async function generateEdgeMiddleware(
+	astroMiddlewareEntryPointPath: URL,
+	outPath: string,
+	netlifyEdgeMiddlewareHandlerPath: URL
+): Promise<URL> {
+	const entryPointPathURLAsString = JSON.stringify(
+		fileURLToPath(astroMiddlewareEntryPointPath).replace(/\\/g, '/')
+	);
+
+	const code = edgeMiddlewareTemplate(entryPointPathURLAsString, netlifyEdgeMiddlewareHandlerPath);
+	const bundledFilePath = join(outPath, 'edgeMiddleware.js');
+	const esbuild = await import('esbuild');
+	await esbuild.build({
+		stdin: {
+			contents: code,
+			resolveDir: process.cwd(),
+		},
+		target: 'es2020',
+		platform: 'browser',
+		outfile: bundledFilePath,
+		allowOverwrite: true,
+		format: 'esm',
+		bundle: true,
+		minify: false,
+		banner: {
+			js: DENO_SHIM,
+		},
+	});
+	return pathToFileURL(bundledFilePath);
+}
+
+function edgeMiddlewareTemplate(middlewarePath: string, netlifyEdgeMiddlewareHandlerPath: URL) {
+	const filePathEdgeMiddleware = fileURLToPath(netlifyEdgeMiddlewareHandlerPath);
+	let handlerTemplateImport = '';
+	let handlerTemplateCall = '{}';
+	if (existsSync(filePathEdgeMiddleware + '.js') || existsSync(filePathEdgeMiddleware + '.ts')) {
+		const stringified = JSON.stringify(filePathEdgeMiddleware.replace(/\\/g, '/'));
+		handlerTemplateImport = `import handler from ${stringified}`;
+		handlerTemplateCall = `handler({ request, context })`;
+	} else {
+	}
+	return `
+	${handlerTemplateImport}
+import { onRequest } from ${middlewarePath};
+import { createContext, trySerializeLocals } from 'astro/middleware';
+export default async function middleware(request, context) {
+	const url = new URL(request.url);
+	const ctx = createContext({ 
+		request,
+		params: {}
+	});
+	ctx.locals = ${handlerTemplateCall};
+	const next = async () => {	
+		request.headers.set(${JSON.stringify(ASTRO_LOCALS_HEADER)}, trySerializeLocals(ctx.locals));
+		return await context.next();
+	};
+
+	return onRequest(ctx, next);
+}
+
+export const config = {
+	path: "/*"
+}
+`;
+}