Astro v5.15.4

Task type →
├─ Static content → [Configuration](./configuration.md) + [CLI](./cli-and-build.md)
├─ CMS/API data → [Content Collections](./content-collections.md) + [Loaders](./content-loaders.md)
├─ Server rendering → [SSR](./ssr-and-app.md) + [Middleware](./middleware.md)
├─ Multi-language → [i18n](./i18n.md)
└─ Client interaction → [Transitions](./transitions.md) + [Server Actions](./server-actions.md)

Input type →
├─ Type-safe server functions → [Server Actions](./server-actions.md) - defineAction()
├─ API endpoints → [SSR](./ssr-and-app.md) - API routes
└─ Auth/validation → [Middleware](./middleware.md) + [Server Actions](./server-actions.md)

Source →
├─ Markdown/MDX → [Content Collections](./content-collections.md) - glob loader
├─ JSON/YAML/TOML → [Loaders](./content-loaders.md) - file loader
├─ External API/CMS → [Loaders](./content-loaders.md) - custom loader
└─ Real-time data → [Content Collections](./content-collections.md) - live collections

Asset →
├─ Images → [Assets](./assets.md) - Image component, getImage()
├─ Fonts → [Configuration](./configuration.md) - font providers
└─ Build → [Configuration](./configuration.md) - build settings

Target →
├─ Static hosting → output: 'static' in [Configuration](./configuration.md)
├─ Serverless → [Integrations](./integrations.md) - adapters
├─ Edge runtime → [SSR](./ssr-and-app.md) - App class
└─ Custom server → [SSR](./ssr-and-app.md) - NodeApp

// src/actions/index.ts
import { defineAction } from 'astro:actions';
import { z } from 'astro/zod';

export const server = {
  contact: defineAction({
    accept: 'form',
    input: z.object({ email: z.string().email(), message: z.string() }),
    handler: async (input) => {
      // Process form data
      return { success: true };
    }
  })
};

<form method="POST" action={actions.contact}>
  <input type="email" name="email" required />
  <textarea name="message" required></textarea>
  <button>Send</button>
</form>

// src/middleware.ts
import { defineMiddleware, sequence } from 'astro:middleware';

export const onRequest = sequence(
  defineMiddleware(async (context, next) => {
    if (context.url.pathname.startsWith('/admin')) {
      if (!context.cookies.get('session')) return context.redirect('/login');
    }
    return next();
  })
);

// src/content/config.ts
import { defineCollection, z } from 'astro:content';

export const collections = {
  blog: defineCollection({
    type: 'content',
    schema: z.object({
      title: z.string(),
      pubDate: z.date(),
      tags: z.array(z.string())
    })
  })
};

// Usage
import { getCollection } from 'astro:content';
const posts = await getCollection('blog', (p) => !p.data.draft);

// Adapter server entry
import { App } from 'astro/app';

const app = new App(manifest);
export default {
  async fetch(request) {
    return app.render(request, {
      clientAddress: request.headers.get('CF-Connecting-IP')
    });
  }
};

// astro.config.mjs
export default defineConfig({
  i18n: {
    defaultLocale: 'en',
    locales: ['en', 'fr', 'es'],
    routing: { prefixDefaultLocale: false }
  }
});

---
import { getRelativeLocaleUrl } from 'astro:i18n';
const frUrl = getRelativeLocaleUrl('fr', '/about');
---

// src/env.d.ts
declare namespace App {
  interface Locals { user?: { id: string } }
}