BrianFreud BrianFreud - 13 days ago 5
Javascript Question

How to get a file or blob from an object URL?

I am allowing the user to load images into a page via drag&drop and other methods. When an image is dropped, I'm using URL.createObjectURL to convert to an object URL to display the image. I am not revoking the url, as I do reuse it.

So, when it comes time to create a FormData object so I can allow them to upload a form with one of those images in it, is there some way I can then reverse that Object URL back into a Blob or File so I can then append it to a FormData object?

Answer

As gengkev alludes to in his comment above, it looks like the best/only way to do this is with an async xhr2 call:

var xhr = new XMLHttpRequest();
xhr.open('GET', 'blob:http%3A//your.blob.url.here', true);
xhr.responseType = 'blob';
xhr.onload = function(e) {
  if (this.status == 200) {
    var myBlob = this.response;
    // myBlob is now the blob that the object URL pointed to.
  }
};
xhr.send();
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