ember file upload to rails, encoding and decoding with base64 - ruby-on-rails

Question

I'm almost there, but I'm having an issue with decoding of the file. When decoding the file is not correct.
The code that I use to upload the file:
createDataSet: function() {
var data = new FormData();
data.append('original_filename', this.get('fileName'));
data.append('datafile', this.get('newData'));
data.append('project_id', this.get('content.id'));
data.append('name', this.get('content.name'));
$.ajax({
url: '/data_sets.json',
data: data,
cache: false,
contentType: false,
processData: false,
dataType: 'json',
type: 'POST',
success: function(data) {
alert('ok');
},
error: function(xhr, data, errorThrown) {
alert('error');
}
});
}
On the Rails side I'm trying to pick this up with the following method:
def create
# take care of the attachement
datasetfilename = Pathname.new(params[:original_filename]).basename
newfile = File.open(datasetfilename, 'w') do |f|
f.write(Base64.decode64(params[:datafile]))
end
#dataset = DataSet.new
#active_data_set = #dataset.active_data_sets.build
#active_data_set.project_id = params[:project_id]
#active_data_set.save
#dataset.name = params[:name]
#dataset.filename = datasetfilename
#dataset.tempfilename = #dataset.savefile newfile
#dataset.save
end
If I use File.open(datasetfilename, 'w') I get an error like this one Encoding::UndefinedConversionError - "\xAB" from ASCII-8BIT to UTF-8. On the other hand, if I open with 'wb' the resulting file is mingled and can't be read.
I already added the meta tag for the file encoding <meta charset="utf-8" /> but without any difference.
If anybody has any hint that would be appreciated.

Answer 1

Just got this working in one of my own controllers, there are 2 main issues:
1) to resolve the encoding issue, use "w:binary" as the write flag instead of "w" (defaults to ASCII)
2) the :datafile params includes some header info "data:text/csv;base64,SUR4CUluZ...", I'm currently splitting on "," but might be better served to decode everything beyond "base64," as I'm not sure if additional commas are allowed.
My working code (slightly different parameter names):
if params.key?(:img_file)
header, data = params[:img_file].split(',')
img_type = header.match(/image\/([a-z]{1,11});/)[1]
file_path = "imgtodo/fund_#{#fund.id}.#{img_type}"
File.open(Rails.root.join('public',file_path).to_s, 'w:binary') do |f|
f.write(Base64.decode64(data))
end
end