Auto add sitemap url in robots.txt

astro.config.mjs

@@ -9,6 +9,7 @@ import image from '@astrojs/image';
 import mdx from '@astrojs/mdx';
 import icon from 'astro-icon';
 import partytown from '@astrojs/partytown';
+import tasks from "./src/utils/tasks"
 
 import { readingTimeRemarkPlugin } from './src/utils/frontmatter.mjs';
 
@@ -63,6 +64,8 @@ export default defineConfig({
         config: { forward: ['dataLayer.push'] },
       })
     ),
+
+    tasks()
   ],
 
   markdown: {

src/utils/tasks.mjs

@@ -0,0 +1,44 @@
+import fs from 'node:fs';
+import os from "node:os";
+
+const tasksIntegration = () => {
+  let config;
+  return {
+    name: 'AstroWind:tasks',
+
+    hooks: {
+      'astro:config:done': async ({ config: cfg }) => {
+        config = cfg;
+        console.log(config);
+      },
+
+      'astro:build:done': async () => {
+        try {
+          const outDir = config.outDir;
+          const publicDir = config.publicDir;
+          const sitemapName = "sitemap-index.xml";
+          const sitemapFile = new URL(sitemapName, outDir);
+          const robotsTxtFile = new URL('robots.txt', publicDir);
+          const robotsTxtFileInOut = new URL('robots.txt', outDir);
+
+          const hasIntegration =
+            Array.isArray(config?.integrations) &&
+            config.integrations?.find((e) => e?.name === '@astrojs/sitemap') !== undefined;
+          const sitemapExists = fs.existsSync(sitemapFile);
+
+          if (hasIntegration && sitemapExists) {
+            const robotsTxt = fs.readFileSync(robotsTxtFile, { encoding: 'utf8', flags: 'a+' });
+
+            if (!robotsTxt.includes("Sitemap:")) {
+              const sitemapUrl = new URL(sitemapName, String(new URL(config.base, config.site)));
+              const content = `${os.EOL}${os.EOL}Sitemap: ${sitemapUrl}`
+              fs.appendFileSync(robotsTxtFileInOut, content, { encoding: 'utf8', flags: 'w' })
+            }
+          }
+        } catch (err) { /* empty */ }
+      },
+    },
+  };
+};
+
+export default tasksIntegration;