Response Methods
Darto provides several methods to control the response sent to the client. Here are the available methods:
send
Sends a response with the specified data.
void main() {
final app = Darto();
app.get('/send', (Request req, Response res) {
res.send('Hello, World!');
});
app.listen(3000);
}json
Sends a JSON response with the specified data.
void main() {
final app = Darto();
app.get('/json', (Request req, Response res) {
res.json({'message': 'Hello, World!'});
});
app.listen(3000);
}end
Ends the response and sends it to the client.
void main() {
final app = Darto();
app.get('/end', (Request req, Response res) {
res.end('Goodbye, World!');
});
app.listen(3000);
}status
Sets the HTTP status code for the response.
void main() {
final app = Darto();
app.get('/status', (Request req, Response res) {
res.status(200).send('OK');
});
app.listen(3000);
}redirect
Redirects the client to a new URL.
void main() {
final app = Darto();
app.get('/redirect', (Request req, Response res) {
res.redirect('https://example.com');
});
app.listen(3000);
}download
Initiates a file download by specifying the file path and optional options.
void main() {
final app = Darto();
app.get('/download', (Request req, Response res) {
res.download('path/to/file.txt', {'filename': 'custom-filename.txt'});
});
app.listen(3000);
}sendFile
Sends a file as a response.
void main() {
final app = Darto();
app.get('/sendfile', (Request req, Response res) {
res.sendFile('path/to/file.txt');
});
app.listen(3000);
}error
Sends an error response with the specified error message.
void main() {
final app = Darto();
app.get('/error', (Request req, Response res) {
res.error('An error occurred.');
});
app.listen(3000);
}cookie
Sets a cookie in the response.
void main() {
final app = Darto();
app.get('/setcookie', (Request req, Response res) {
res.cookie('cookieName', 'cookieValue');
res.send('Cookie set');
});
app.listen(3000);
}clearCookie
Clears a cookie from the response.
void main() {
final app = Darto();
app.get('/clearcookie', (Request req, Response res) {
res.clearCookie('cookieName');
res.send('Cookie cleared');
});
app.listen(3000);
}render
Renders a template with the specified data and sends it as a response.
void main() {
final app = Darto();
// Set the directory and view engine as shown in template engine documentation
// ...
app.get('/render', (Request req, Response res) {
res.render('template', {'data': 'Hello, World!'});
});
app.listen(3000);
}set
You can use this method to set a header customization or change a header type
void main() {
final app = Darto();
app.get('/html', (Request req, Response res) {
res.set('Content-Type', 'text/html');
res.send('<h1>Hello custom header</h1>');
});
app.listen(3000);
}type
Sets the Content-Type header based on a known MIME type or file extension. This method is a shorthand for set(‘Content-Type’, value) and automatically maps file extensions like ‘json’, ‘html’, ‘png’ to their corresponding MIME types.
void main() {
final app = Darto();
app.get('/html', (Request req, Response res) {
res.type('html').send('<h1>Hello HTML</h1>');
});
app.get('/json', (Request req, Response res) {
res.type('json').send('{"message":"Hello JSON"}');
});
app.listen(3000);
}pipe
Pipes a stream (such as a file or another request) directly into the response. This is useful for streaming large files, proxies, or data chunks without loading them entirely into memory.
import 'dart:io';
void main() {
final app = Darto();
app.get('/video', (Request req, Response res) {
final fileStream = File('video.mp4').openRead();
res.set('Content-Type', 'video/mp4');
res.pipe(fileStream);
});
app.listen(3000);
}notFound
New method: res.notFound() - Sends a 404 response.
import 'dart:io';
void main() {
final app = Darto();
app.get('/hello', (Request req, Response res) {
return res.notFound();
});
app.listen(3000);
}text
Sends a plain text response.
import 'dart:io';
void main() {
final app = Darto();
app.get('/hello', (Request req, Response res) {
return res.text('Hello, World!');
});
app.listen(3000);
}html
Sends a plain text/html response.
import 'dart:io';
void main() {
final app = Darto();
app.get('/hello', (Request req, Response res) {
return res.html('<h1>Hello, World!</h1>');
});
app.listen(3000);
}setRender
Set a global template for render method.
import 'dart:io';
void main() {
final app = Darto();
app.engine('mustache', join(Directory.current.path, 'lib', 'pages'));
app.use((Request req, Response res, Next next) {
res.setRender((content) {
return res.html('''
<html>
<head>
<title>My layout</title>
</head>
<body>
<h1>My Template Layout</h1>
$content
</body>
</html>
''');
});
next();
});
app.get('/', (Request req, Response res) {
res.render('index', {
'title': 'Welcome',
'header': 'Hello',
'message': 'This is a sample mustache template rendered with Darto.',
});
});
app.listen(3000);
}Gzip Compression
Darto supports optional Gzip compression for responses like sendFile() and json() when the client supports it (Accept-Encoding: gzip).
If gzip is enabled, Darto will compress the response on the fly to improve performance over the network — especially for large files or JSON data.
You can enable or disable gzip at the framework or response level (depending on your config system).
void main() {
final app = Darto(gzip: true); // enables gzip globally
app.get('/data', (Request req, Response res) {
res.json({'message': 'This response may be gzipped'});
});
app.get('/file', (Request req, Response res) {
res.sendFile('static/large.txt'); // will be sent with gzip if supported
});
app.listen(3000);
}By default, Darto will:
- Check if the client supports gzip via the Accept-Encoding header.
- Compress responses only if gzip is enabled in the framework config.
- Skip gzip for already compressed files (e.g., .zip, .gz, .png).