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I'd like to use Exif.js to read JPEG EXIF tags from a local file. However, the javascript lib uses XMLHttpRequest to read JPG files as a BinaryFile:

function getImageData(oImg, fncCallback) 
{
    BinaryAjax(
        oImg.src,
        function(oHTTP) {
            var oEXIF = findEXIFinJPEG(oHTTP.binaryResponse);
            oImg.exifdata = oEXIF || {};
            if (fncCallback) fncCallback();
        }
    )
}

When I use <input type="file"> I get an HTML5 File object which I can read using a FileReader but I don't know how to convert this to a BinaryFile:

_initHTML5FileReader = function() {
  var chooseFile;
  chooseFile = document.getElementById("html5-get-file");
  chooseFile.onchange = function(e) {
    var file;
    file = e.currentTarget.files[0];
    var reader;
    reader = new FileReader();
    reader.onloadend = function(ev) {
      var dataUrl = ev.target.result;
      // How do I change this to a BinaryFile???
    };
    reader.readAsDataURL(file);
    return false;
  };
};

But I also using AppGyver Steroids (PhoneGap) which serves my page from http://localhost/index.html, and when I try to use Exif.js, I get this CORS error:

XMLHttpRequest cannot load data:image/jpeg;base64,/9j/4X2cRXhpZgAASUkqAAgAAAAOAA8BAgAKAAAAtgAAABABAgAI…N6gn14dm6BmJyMdYaMhX16hI+HgIWLj5aWkJOaiHF7hoV+dnBwc3Jzbm14hGlZcIaWlXFEU3OB. Received an invalid response. Origin 'http://localhost:4000' is therefore not allowed access.

Is there any way to configure XmlHttpRequest to serve a local File object without the CORS error?

michael
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  • Does the error message indicate which line of code is failing? Is it readAsDataURL, or something else? – monsur Apr 23 '14 at 02:22
  • no, the error is unrelated to FileReader.readAsDataURL(). The error is from XMLHttpRequest. I was trying to find a workaround using FileReader - some way to get a BinaryFile from the FileReader, but those APIs do not overlap. Is there another way? – michael Apr 24 '14 at 02:49

0 Answers0