m4d_router 0.2.18

A browser routing library for Dart

Material4Dart router

m4d_router is a client routing library for Dart. It helps make building single-page web apps and using HttpServer easier.

Installation

Add this package to your pubspec.yaml file:

dependencies:
  m4d_router: any

Then, run pub get to download and link in the package.

Example

Live: m4d_router.example.mikemitterer.at
Source on GitHub

void main() {
    final router = new Router();

    configLogging(show: Level.INFO);
    _configRouter(router);

    dom.querySelector('#output').text = 'Your Dart app is running.';
}

void _configRouter(final Router router ) {

    router
        ..addRoute(name: "Test I", path: new UrlPattern('/#/test'),
            enter: (final RouteEnterEvent event) {
                _log(event.route.title);
                _logger.info("Path: ${event.path} Params: ${event.params.join(",")}");
                _showImage("https://upload.wikimedia.org/wikipedia/commons/1/11/Test-Logo.svg");
            })

        ..addRoute(name: 'Cats', path: new ReactPattern('/cats'),
            enter: (final RouteEnterEvent event) {
                _log(event.route.title);
                _logger.info("Path: ${event.path} Params: ${event.params.join(",")}");
                _showImage("https://i1.wp.com/www.oxygen.ie/wp-content/uploads/2016/11/main_1500.jpg?resize=750%2C400");
            })

        ..addRoute(name: 'Specific cat', path: new ReactPattern(r'/cats/(\w+)'),
            enter: (final RouteEnterEvent event) {
                _log("${event.route.title}: ${event.params.join(",")}");
                _logger.info("Path: ${event.path} Params: ${event.params.join(",")}");
                if(event.params.first.toLowerCase() == "grumpy") {
                    _showImage("https://pbs.twimg.com/media/CsW0pmxUsAAuvEN.jpg");
                } else {
                    _showImage("https://catzone-tcwebsites.netdna-ssl.com/wp-content/uploads/2014/09/453768-cats-cute.jpg");
                }
            })

        ..addRoute(name: "Google for cats", path: new ReactPattern('/google'),
            enter: (final RouteEnterEvent event) {
                _log(event.route.title);
                _logger.info("Path: ${event.path} Params: ${event.params.join(",")}");
                _showImage("https://upload.wikimedia.org/wikipedia/commons/a/a5/Google_Chrome_icon_%28September_2014%29.svg");
            })
    ;

    // optional
    router.onEnter.listen((final RouteEnterEvent event) {
        _logger.info("RoutEvent ${event.route.title} -> ${event.route.urlPattern.pattern}");
    });

    // optional
    router.onError.listen((final RouteErrorEvent event) {
        _logger.info("RouteErrorEvent ${event.exception}");
    });

    router.listen(); // Start listening
}

void _log(final String logMessage) {
    final logElement = dom.querySelector("#log") as dom.UListElement;
    logElement.append(new dom.LIElement()..text = logMessage);
}

void _showImage(final String url) {
    final img = dom.querySelector("img") as dom.ImageElement;
    img.src = url;
}

UrlPattern

Route is built around UrlPattern a class that matches, parses and produces URLs. A UrlPattern is similar to a regex, but constrained so that it is reversible, given a UrlPattern and a set of arguments you can produce the URL that when parsed returns those same arguments. This is important for keeping the URL space for your app flexible so that you can change a URL for a resource in one place and keep your app working.

Route lets you use the same URL patterns for client-side and server-side routing. Just define a library containing all your URLs.

As an example, consider a blog with a home page and an article page. The article URL has the form /article/1234. We want to show articles without reloading the page.

Routing

On the browser, there is a Router class that associates UrlPatterns to handlers. Given a URL, the router finds a pattern that matches, and invokes its handler. The handlers are then responsible for rendering the appropriate changes to the page.