Basic Routing

• Routing

• Route Parameters

  • Parsing Parameters

• RegExp Routes

• Mounting and Sub-Apps

• Route Groups

• Extended Documentation

• Next Up...

Routing

There is only one method responsible for adding routes to your application:

app.addRoute('<method>', '<path>', requestHandler);

However, the following methods are available for convenience, and are the ones you will use most often. Each method's name responds to an HTTP request method. For example, a route declared with app.get(...), will respond to HTTP GET requests.

app.get('<path>', requestHandler);
app.post('<path>', requestHandler);
app.patch('<path>', requestHandler);
app.delete('<path>', requestHandler);

Your requestHandler should take the following form:

typedef FutureOr<dynamic> RequestHandler(RequestContext req, ResponseContext res);

Your requestHandler can return any Dart value, whether a function, or an object. See the Requests and Responses pages for detailed documentation.

Route paths do not have to begin with a forward slash, as leading and trailing slashes are stripped from route paths internally.

Route Parameters

Say you're building an API, or an MVC application. You typically want to serve the same view template on multiple paths, corresponding to different ID's. You can do this as follows, and all parameters will be available via req.params:

app.get('/todos/:id', (req, res) async => {'id': req.params['id']});

Remember, route parameters must be preceded by a colon (':'). Parameter names must start with a letter or underscore, optionally followed by letters, underscores, or numbers. Parameters will match any character except a forward slash ('/') in a request URI.

Examples:

• :id

• :_hello

• :param123

• info_about_:username

Parsing Parameters

With a special syntax, you can build routes that automatically parse parameters as ints or doubles:

app
  ..get('/add/int:number', (req, res) => req.params['number'] * 3)
  ..get('/multiply/double:number', (req, res) => req.params['number'] * 5.0);

RegExp Routes

Route parameters can also have custom regular expressions, to remove the requirement of manual parsing. Simply enclose the regular expression in a set of parentheses following the parameter's name.

app.get(r'/number/:num([0-9]+(\.[0-9])?)', ...);

Sub-Apps

You can mount routers, or use entire sub-apps.

var app = Angel();
app.get('/', 'Hello!');

var subRouter = Router()..get('/', 'Subroute');
app.mount('/sub', subApp);
// Now, you can visit /sub and receive the message "Subroute"

var subApp = Angel()..get('/hello', 'world');
app.use('/api', subApp);

// GET /api/hello returns "world"

Route Groups

Routes can also be grouped together. Route parameters will be applied to sub-routes automatically. Route groups can be nested as well.

app.group('/user/:id', (router) {
  router
    ..get('/messages', (String id) => fetchUserMessages(id))
    ..group('/nested', ...);
});

Extended Documentation

For more documentation on the router, see Angel3 Route Repository. angel3_route has no dart:io or dart:mirrors dependency, and it also supports browser use (both hash and push state).

Next Up

Learn how Requests and Responses let you reuse functionality across your entire routing setup.