Semi-sanely resolve local paths to URLs according to jupyter-widgets/…

…ipywidgets#2800

js/rej-widget.js

@@ -6,15 +6,13 @@ __webpack_public_path__ = PageConfig.getOption('fullStaticUrl') + '/'
 
 import App from './App'
 
-const toLabURL = (localPath) => localPath ? `${PageConfig.getBaseUrl()}files/${localPath}` : null
-
 export class RejWidget extends VueWidget {
  computedProps(props) {
  window.rej = this
  return {
  ...props,
- imageryURL: toLabURL(props.imageryPath),
- referenceURL: toLabURL(props.referencePath),
+ imageryURL: this.getDownloadUrlFor(props.imageryPath),
+ referenceURL: this.getDownloadUrlFor(props.referencePath),
  ptsCallback: ptsFile => {
  debugger;
  console.log("Sending it by message")

js/utils/vue-widget.js

@@ -38,6 +38,14 @@ export class VueWidget extends DOMWidgetView {
  this.el.appendChild(el)
  this.vm.$mount(el)
  }
+ async getDownloadUrlFor(fsPath) {
+ // Resolve widgets using rendermime, as per the following workaround:
+ // https://github.com/jupyter-widgets/ipywidgets/issues/2800#issuecomment-616844788
+ // TODO: follow this issue, submit a PR to implement this properly if we have time
+ const resolver = this.model.widget_manager.rendermime.resolver
+ const resolvedPath = await resolver.resolveUrl(fsPath)
+ return await resolver.getDownloadUrl(resolvedPath)
+ }
  // TODO: implement
  // this.vue.$destroy()
 }