Image Upload AngularJS

Hi,

(I know that this is often asked but I can't find answer which would satisfy my needs)

I'm using CKEditor with AngularJS and I'm now trying to make work simple image upload.

This is what I do: just 'unhide' uploadTab, but I can't set URL to upload image. It's always 'undefined'

 CKEDITOR.on "dialogDefinition", (ev) ->
      dialogName = ev.data.name
      dialogDefinition = ev.data.definition
      if dialogName is "image"
        uploadTab = dialogDefinition.getContents("Upload")
        uploadTab.hidden = false
        dialogDefinition.onLoad = ->
          console.log("upload")
  options=
    "removePlugins": "sourcearea"
    "filebrowserUploadUrl": 'api/upload',
    "filebrowserImageUploadUrl": 'api/upload'
  editorangular = CKEDITOR.inline(element[0], options) 
  scope.$watch attrs.ckedit, (value) ->
    editorangular.setData value

how can I fix this and set propper URL?

also what should be the response for ckeditor? Just relative file url, or some object?