How do I use AngularDart when my static files are on a CDN with a varying URL?

Question

I'm using AngularDart for a new application of mine. I have a component set up like so:

@NgComponent(
    selector: 'game-timeline',
    templateUrl: '/static/dart/game/web/views/timelineview.html',
    cssUrl: '/static/dart/game/web/views/timelineview.css',
    publishAs: 'ctrl'
)

But my problem is, the template and css locations aren't necessarily known at build-time. They'll be on a CDN with a unique deploy-identifier on them. Something like...

http://cdn.domain.com/static/30294832098/dart/game/web/views/timelineview.html

And that number varies every deploy.

The path seems to be relative to the html page it's hosted on, which is not on the CDN, so I can't just use a relative path (../blah/blah)

I can inject a JS variable into the page telling me where the static root it, if that helps.

The main .dart/.js file is loaded from the CDN, but I can't seem to make it be relative to that.

Any ideas?

Update, here's my full solution adapted from pavelgj's great answer that reads in a js variable called STATIC_URL on the page.

import 'package:angular/angular.dart';
import 'package:js/js.dart' as js;

class CDNRewriter implements UrlRewriter {
  String staticUrl;

  CDNRewriter() {
    var context = js.context;
    staticUrl = js.context.STATIC_URL;
  }

  String call(String url) {
    if (url.startsWith('/static/')) {
      return _rewriteCdnUrl(url);
    }
    return url;
  } 

  String _rewriteCdnUrl(String url) {
    return url.replaceFirst(new RegExp(r'/static/'), staticUrl);
  }
}

Answer 1

You can implement a custom UrlRewriter. UrlRewriter is called for all resources fetched via angular Http service, including templates and css.

class MyUrlRewriter implements UrlRewriter {
  String call(String url) {
    if (url.startsWith('/static/')) {
      return _rewriteCdnUrl(url);
    }
    return url;
  } 
}

myModule.type(UrlRewriter, implementedBy: MyUrlRewriter);