Static Files

Daho provides two mechanisms for serving content without Dart route handlers.

serveStatic()

Serve files from a local directory under a URL prefix. Files are served directly by the H2O kernel via zero-copy file serving — no Dart code runs.

void setupRoutes(Daho app) {
  // Serve files from ./public/ under the root URL path
  app.serveStatic('/', 'public');

  // Serve files from ./assets/ under /static
  app.serveStatic('/static', 'assets');

  // Regular Dart routes still work alongside static serving
  app.get('/api/data', (req, res) => res.ok({'key': 'value'}));
}

With the above setup:

• GET /index.html → serves ./public/index.html
• GET /static/logo.png → serves ./assets/logo.png
• GET /api/data → handled by Dart

INFO

Static files are served by H2O's built-in file handler with zero-copy I/O. This is the fastest way to serve files — the data goes directly from the filesystem to the network socket without entering Dart's heap.

fastPath()

Register a fixed response for a specific path, served entirely in C. The Dart route pipeline is never invoked.

void setupRoutes(Daho app) {
  // Health check — always returns the same JSON
  app.fastPath(
    '/health',
    '{"status": "ok"}',
    contentType: 'application/json',
  );

  // Simple text response
  app.fastPath('/ping', 'pong');

  // Regular routes still work
  app.get('/users', (req, res) => res.ok('users list'));
}

When to Use Each

Feature	Use Case	Performance
serveStatic()	Serving HTML, CSS, JS, images, any files from disk	Zero-copy, H2O handles directly
fastPath()	Health checks, status endpoints, fixed responses	Served from C memory, zero Dart
Regular routes	Dynamic content, API endpoints, anything that needs logic	Full Dart dispatch pipeline

WARNING

Fast paths bypass the entire middleware chain. If you need middleware (auth, logging, CORS) on an endpoint, use a regular route instead.

Example: Full Setup

void setupRoutes(Daho app) {
  // Global middleware
  app.use(Middlewares.logger());
  app.use(Middlewares.cors());

  // Fast paths (no middleware, no Dart)
  app.fastPath('/health', '{"status": "ok"}', contentType: 'application/json');

  // Static files (served by H2O, no Dart)
  app.serveStatic('/', 'public');

  // API routes (full Dart pipeline)
  final api = app.group('/api');
  api.get('/users', listUsers);
  api.post('/users', createUser);
}

void main() {
  final app = Daho();
  app.listen(8080, routes: setupRoutes);
}