feat: add generic page-ssr plugin

packages/astro/src/core/create-vite.ts

@@ -14,6 +14,7 @@ import astroIntegrationsContainerPlugin from '../vite-plugin-integrations-contai
 import jsxVitePlugin from '../vite-plugin-jsx/index.js';
 import markdownVitePlugin from '../vite-plugin-markdown/index.js';
 import astroScriptsPlugin from '../vite-plugin-scripts/index.js';
+import astroScriptsPagePlugin from '../vite-plugin-scripts/page.js';
 import { createCustomViteLogger } from './errors.js';
 import { resolveDependency } from './util.js';
 
@@ -80,6 +81,7 @@ export async function createVite(
 			jsxVitePlugin({ config: astroConfig, logging }),
 			astroPostprocessVitePlugin({ config: astroConfig }),
 			astroIntegrationsContainerPlugin({ config: astroConfig }),
+			astroScriptsPagePlugin({ config: astroConfig }),
 		],
 		publicDir: fileURLToPath(astroConfig.publicDir),
 		root: fileURLToPath(astroConfig.root),

packages/astro/src/vite-plugin-scripts/page.ts

@@ -0,0 +1,53 @@
+import { Plugin as VitePlugin } from 'vite';
+import { AstroConfig } from '../@types/astro.js';
+import { PAGE_SSR_SCRIPT_ID } from './index.js';
+
+import { resolvePages } from '../core/util.js';
+import ancestor from 'common-ancestor-path';
+import MagicString from 'magic-string';
+
+export default function astroScriptsPostPlugin({ config }: { config: AstroConfig }): VitePlugin {
+	function normalizeFilename(filename: string) {
+		if (filename.startsWith('/@fs')) {
+			filename = filename.slice('/@fs'.length);
+		} else if (filename.startsWith('/') && !ancestor(filename, config.root.pathname)) {
+			filename = new URL('.' + filename, config.root).pathname;
+		}
+		return filename;
+	}
+
+	return {
+		name: 'astro:scripts:post',
+		enforce: 'post',
+
+		transform(this, code, id, options) {
+			if (!options?.ssr) return;
+
+			const filename = normalizeFilename(id);
+			let fileUrl: URL;
+			try {
+				fileUrl = new URL(`file://${filename}`);
+			} catch (e) {
+				// If we can't construct a valid URL, exit early
+				return;
+			}
+
+			const isPage = fileUrl.pathname.startsWith(resolvePages(config).pathname);
+			if (!isPage) return;
+			const parts = fileUrl.pathname.slice(resolvePages(config).pathname.length).split('/');
+			for (const part of parts) {
+				if (part.startsWith('_')) return;
+			}
+			const hasInjectedScript = config._ctx.scripts.some((s) => s.stage === 'page-ssr');
+			if (!hasInjectedScript) return;
+
+			const s = new MagicString(code, { filename });
+			s.prepend(`import '${PAGE_SSR_SCRIPT_ID}';\n`);
+
+			return {
+				code: s.toString(),
+				map: s.generateMap(),
+			}
+		},
+	};
+}