urlencoding in Dart

var uri = 'http://example.org/api?foo=some message';
var encoded = Uri.encodeFull(uri);
assert(encoded == 'http://example.org/api?foo=some%20message');

var decoded = Uri.decodeFull(encoded);
assert(uri == decoded);

http://www.dartlang.org/docs/dart-up-and-running/contents/ch03.html#ch03-uri