Ruby Shrine - crop & direct upload Safari issue - ruby-on-rails

Question

I am implementing direct upload with Shrine, jquery.fileupload and cropper.js
in the add portion I am loading the image from the file upload to modal, define the cropper and show the modal
if (data.files && data.files[0]) {
var reader = new FileReader();
var $preview = $('#preview_avatar');
reader.onload = function(e) {
$preview.attr('src', e.target.result); // insert preview image
$preview.cropper({
dragMode: 'move',
aspectRatio: 1.0 / 1.0,
autoCropArea: 0.65,
data: {width: 270, height: 270}
})
};
reader.readAsDataURL(data.files[0]);
$('#crop_modal').modal('show', {
backdrop: 'static',
keyboard: false
});
}
Then on the modal button click I get the cropped canvas call on it toBlob and submit to S3
$('#crop_button').on('click', function(){
var options = {
extension: data.files[0].name.match(/(\.\w+)?$/)[0], // set extension
_: Date.now() // prevent caching
};
var canvas = $preview.cropper('getCroppedCanvas');
$.getJSON('/images/cache/presign', options).
then(function (result) {
data.formData = result['fields'];
data.url = result['url'];
data.paramName = 'file';
if (canvas.toBlob) {
canvas.toBlob(
function (blob) {
var file = new File([blob], 'cropped_file.jpeg');
console.log('file', file);
data.files[0] = file;
data.originalFiles[0] = data.files[0];
data.submit();
},
'image/jpeg'
);
}
});
});
After the upload to S3 is done I am writing to image attributes to hidden field, closing the modal and destroying the cropper
done: function (e, data) {
var image = {
id: data.formData.key.match(/cache\/(.+)/)[1], // we have to remove the prefix part
storage: 'cache',
metadata: {
size: data.files[0].size,
filename: data.files[0].name.match(/[^\/\\]*$/)[0], // IE returns full path
// mime_type: data.files[0].type
mime_type: 'image/jpeg'
}
};
console.log('image', image);
$('.cached-avatar').val(JSON.stringify(image));
$('#crop_modal').modal('hide');
$('#preview_avatar').cropper('destroy');
}
An chrome everything worked fine from the very beginning, but then I figured out the safari has no toBlob functionality.
I found this one:
https://github.com/blueimp/JavaScript-Canvas-to-Blob
And toBlob is not a function error was gone..
Now I can not save the image due to some mime type related issue.
I was able to find out the exact location where it fails on safari but not chrome.
determine_mime_type.rb line 142
on line 139 in the options = {stdin_data: io.read(MAGIC_NUMBER), binmode: true}
the stdin_data is empty after the io.read
Any ideas?
Thank you!
UPDATE
I was able to figure out that the url to the cached image returned by the
$.getJSON('/images/cache/presign', options)
returns empty file when cropped and uploaded from safari.

Answer 1

So as I mentioned in the question safari uploaded empty file once it was cropped by cropper.js.
The problem clearly originated from this block:
if (canvas.toBlob) {
canvas.toBlob(
function (blob) {
var file = new File([blob], 'cropped_file.jpeg');
console.log('file', file);
data.files[0] = file;
data.originalFiles[0] = data.files[0];
data.submit();
},
'image/jpeg'
);
}
I found in some comment on one of the articles I read that safari does some thing like "file.toString" which in my case resulted in empty file upload.
I appended the blob directly without creating a file from it first and everything worked fine.
if (canvas.toBlob) {
canvas.toBlob(
function (blob) {
data.files[0] = blob;
data.files[0].name = 'cropped_file.jpeg';
data.files[0].type = 'image/jpeg';
data.originalFiles[0] = data.files[0];
data.submit();
},
'image/jpeg'
);
}