Netlify Edge function support (#3148)

* Netlify Edge function support

* Update readme with edge function information

* Adds a changeset

* Disable running edge function test in CI for now

1 files changed, 65 insertions, 1 deletions

diff --git a/packages/integrations/netlify/src/integration-functions.ts b/packages/integrations/netlify/src/integration-functions.ts
index 5b687cda4..2720eb591 100644
--- a/packages/integrations/netlify/src/integration-functions.ts
+++ b/packages/integrations/netlify/src/integration-functions.ts
@@ -1 +1,65 @@
-export { netlifyFunctions as default } from './index.js';
+import type { AstroAdapter, AstroIntegration, AstroConfig } from 'astro';
+import fs from 'fs';
+
+export function getAdapter(): AstroAdapter {
+	return {
+		name: '@astrojs/netlify/functions',
+		serverEntrypoint: '@astrojs/netlify/netlify-functions.js',
+		exports: ['handler'],
+		args: {},
+	};
+}
+
+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.outDir = dist;
+				} else {
+					config.outDir = new URL('./netlify/', config.root);
+				}
+			},
+			'astro:config:done': ({ config, setAdapter }) => {
+				setAdapter(getAdapter());
+				_config = config;
+			},
+			'astro:build:start': async ({ buildConfig }) => {
+				entryFile = buildConfig.serverEntry.replace(/\.m?js/, '');
+				buildConfig.client = _config.outDir;
+				buildConfig.server = new URL('./functions/', _config.outDir);
+			},
+			'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`;
+					} else {
+						const pattern =
+							'/' + route.segments.map(([part]) => (part.dynamic ? '*' : part.content)).join('/');
+						_redirects += `
+${pattern}    /.netlify/functions/${entryFile}    200`;
+					}
+				}
+
+				// Always use appendFile() because the redirects file could already exist,
+				// e.g. due to a `/public/_redirects` file that got copied to the output dir.
+				// If the file does not exist yet, appendFile() automatically creates it.
+				await fs.promises.appendFile(_redirectsURL, _redirects, 'utf-8');
+			},
+		},
+	};
+}
+
+export { netlifyFunctions, netlifyFunctions as default };