Netlify adapter (#2879)

* Netlify adapter

* Remove package.json export that doesnt exist

* Fix out path

* Make netlifyFunctions the default

* Make the dist configurable

* Add an export for the functions

* Append of the file exists

3 files changed, 110 insertions, 0 deletions

diff --git a/packages/integrations/netlify/src/index.ts b/packages/integrations/netlify/src/index.ts
new file mode 100644
index 000000000..4ddacfaf2
--- /dev/null
+++ b/packages/integrations/netlify/src/index.ts
@@ -0,0 +1,64 @@
+import type { AstroAdapter, AstroIntegration, AstroConfig } from 'astro';
+import fs from 'fs';
+
+export function getAdapter(site: string | undefined): AstroAdapter {
+	return {
+		name: '@astrojs/netlify',
+		serverEntrypoint: '@astrojs/netlify/netlify-functions.js',
+		exports: ['handler'],
+		args: { site }
+	};
+}
+
+interface NetlifyFunctionsOptions {
+	dist?: URL;
+}
+
+function netlifyFunctions({ dist }: NetlifyFunctionsOptions = {}): AstroIntegration {
+	let _config: AstroConfig;
+	let entryFile: string;
+	return {
+		name: '@astrojs/netlify',
+		hooks: {
+			'astro:config:setup': ({ config }) => {
+				if(dist) {
+					config.dist = dist;
+				} else {
+					config.dist = new URL('./netlify/', config.projectRoot);
+				}
+			},
+			'astro:config:done': ({ config, setAdapter }) => {
+				setAdapter(getAdapter(config.buildOptions.site));
+				_config = config;
+			},
+			'astro:build:start': async({ buildConfig }) => {
+				entryFile = buildConfig.serverEntry.replace(/\.m?js/, '');
+				buildConfig.client = _config.dist;
+				buildConfig.server = new URL('./functions/', _config.dist);
+			},
+			'astro:build:done': async ({ routes, dir }) => {
+				const _redirectsURL = new URL('./_redirects', dir);
+
+				// Create the redirects file that is used for routing.
+				let _redirects = '';
+				for(const route of routes) {
+					if(route.pathname) {
+						_redirects += `
+${route.pathname}    /.netlify/functions/${entryFile}    200`
+					}
+				}
+
+				if(fs.existsSync(_redirects)) {
+					await fs.promises.appendFile(_redirectsURL, _redirects, 'utf-8');
+				} else {
+					await fs.promises.writeFile(_redirectsURL, _redirects, 'utf-8');
+				}
+			}
+		},
+	};
+}
+
+export {
+	netlifyFunctions,
+	netlifyFunctions as default
+};
diff --git a/packages/integrations/netlify/src/integration-functions.ts b/packages/integrations/netlify/src/integration-functions.ts
new file mode 100644
index 000000000..540fcdee2
--- /dev/null
+++ b/packages/integrations/netlify/src/integration-functions.ts
@@ -0,0 +1,3 @@
+export {
+	netlifyFunctions as default
+} from './index.js';
diff --git a/packages/integrations/netlify/src/netlify-functions.ts b/packages/integrations/netlify/src/netlify-functions.ts
new file mode 100644
index 000000000..cf6c871a9
--- /dev/null
+++ b/packages/integrations/netlify/src/netlify-functions.ts
@@ -0,0 +1,43 @@
+import { SSRManifest } from 'astro';
+import type { Handler } from "@netlify/functions";
+import { App } from 'astro/app';
+import { polyfill } from '@astrojs/webapi';
+
+polyfill(globalThis, {
+	exclude: 'window document',
+});
+
+interface Args {
+	site?: string;
+}
+
+export const createExports = (manifest: SSRManifest, args: Args) => {
+	const app = new App(manifest);
+	const site = new URL(args.site ?? `https://netlify.com`);
+
+	const handler: Handler = async (event) => {
+		const headers = new Headers(event.headers as any);
+		const request = new Request(new URL(event.path, site).toString(), {
+			method: event.httpMethod,
+			headers
+		});
+
+		if(!app.match(request)) {
+			return {
+				statusCode: 404,
+				body: 'Not found'
+			};
+		}
+
+		const response = await app.render(request);
+		const body = await response.text();
+
+		return {
+			statusCode: 200,
+			headers: Object.fromEntries(response.headers.entries()),
+			body
+		};
+	}
+
+	return { handler };
+};