Using meteor upload how can the cleint get the url of the file on the server

How can the client get the url after the file has been uploaded using meteor uploads, and put it in a string.

I think it would be helpful for people to have more context or even example code about this question.

I am trying to put a pure photo post, feature next to my articles on the page. I am using the same controller to subscribe to both articles and photos posts. What i need to do that is the url of the stored photo and a category field in the same mongo collocation the admin user sets the category and uploads the image but once the image is uploaded i need the url address so I can insert the doc into mongodb.

example of base mongo collection template

photoInsert: function(photoAttributes) {
check(this.url, String);
check(photoAttributes, {
  url: String, //needs to be auto set after upload.
  category:String //admin user set