CORS issue, using Rack-cors gem with cloudfront assets

I have a rails 4 app hosted on AWS with assets served on cloudfront. I use the rack-cors gem to add cors headers. My rack-cors settings allows only check for my domain hence cannot provide jsfiddle example.

curl -H "Origin:https://staging.beenlightened.com" -I https://d3czu6zp3f06wr.cloudfront.net/assets/vitality4-064f8c9848768917287e1a7dbcec1749.png

Notice CORS headers are added correctly. However html2canvas still complains about cors headers not being present.

[fuggfuggfugg]

From what I remember: When the page loads the first time, the browser caches the image. Since the domain is the same, the CORS headers are not present. So now when I try to print the image it used the cached image and html2canvas complained about CORS headers not present.

My only solution was to add a timestamp in the ImageContainer method inside the library like so:

if (cors) {
        self.image.crossOrigin = "anonymous";
        // special check for cloudfront images only.
        if (src.toLowerCase().includes("cloudfront")){
          src = src + '?123';
        }
    }

I’ve spent ages on this damn thing. Hope it works for you man.

[fuggfuggfugg]

Can you make an example on codepen or jsfiddle?