Rest service and client in DART

The DART language looks like a promising way to write rich clients in a high level language. I have been looking at DART and the Ruby to JavaScript compiler Opal as possible (but not likely) substitutes for Clojurescript with Clojure back ends. It took me a little while to get a simple REST service and client working in development mode inside the DART IDE. The following code snippets might save you some time. Here is a simple service that returns some JSON data:
import 'dart:io';
import 'dart:json' as JSON;

main() {
  var port = 8080;
  HttpServer.bind('localhost', port).then((HttpServer server) {
    print('Server started on port: ${port}');
    server.listen((HttpRequest request) {
      var resp = JSON.stringify({
        'name': 'Mark',
        'hobby': 'hiking'}
It is required to set Access-Control-Allow-Origin. Here is the client code (I am not showing the HTML stub that loads the client):
import 'dart:html';
import 'dart:json';

void main() {
  // call the web server asynchronously
  var request = HttpRequest.getString("http://localhost:8080/")

void onDataLoaded(String responseText) {
  var jsonString = responseText;
  Map map = parse(jsonString);
  var name = map["name"];
  var hobby = map["hobby"];
  query("#sample_text_id").text =
      "My name is $name and my hobby is $hobby";
The call to query(…) is similar to a jQuery call. As you might guess, “#sample_text_id” refers to a DOM element from the HTML page with this ID. DART on the client side seems to be very well supported both with components and tooling. I think that DART on the server side is still a work in progress but looks very promising.


Post a Comment

Popular posts from this blog

Ruby Sinatra web apps with background work threads

My Dad's work with Robert Oppenheimer and Edward Teller

Time and Attention Fragmentation in Our Digital Lives