How to save a base64 string as an image using ruby
Ruby on-RailsRubyImageFile IoBase64Ruby on-Rails Problem Overview
I'm integrating my Ruby on Rails app with a usps shipping system. Once you make a postage request, you pay for that postage and it's nonrefundable.
Postage requests will return you an xml response including a base64 string, which is the shipping label.
I'm able to render the shipping label in a view, however to make it foolproof, I would like to be able to save that base64 string as an image on my server in the event that something happens to the shipping label between generation (paying for it) and mailing so it may be reprinted without buying a new one.
My first thoughts were as follows
# Attempt 1
File.open('shipping_label.gif', 'w+') {|f|
f.puts Base64.decode64(base_64_encoded_data)
}
# Attempt 2
File.open('shipping_label.gif', 'w+') {|f|
f.puts Base64.decode64(Base64.decode64(base_64_encoded_data))
}
Neither work.
Ruby on-Rails Solutions
Solution 1 - Ruby on-Rails
When writing binary data to a file, such as is the case with an image, you cannot use text printing tools like IO#puts
.
There's two things you need to ensure:
- You need to be writing in binary mode to avoid any possible LF to CRLF expansion.
- You must use
write
instead ofputs
aswrite
can work on arbitrary data, butputs
(literally "put string") is exclusively for text.
Combining these you get:
File.open('shipping_label.gif', 'wb') do |f|
f.write(Base64.decode64(base_64_encoded_data))
end
Solution 2 - Ruby on-Rails
Other answers are pretty close, but usually assume that base64 stream will contain PNG data. This is not always the case so I suggest to use mime types library to establish correct file extension:
REGEXP = /\Adata:([-\w]+\/[-\w\+\.]+)?;base64,(.*)/m
data_uri_parts = data_url.match(REGEXP) || []
extension = MIME::Types[data_uri_parts[1]].first.preferred_extension
file_name = "myfilename.#{extension}"
File.open(file_name, 'wb') do |file|
file.write(Base64.decode64(data_uri_parts[2]))
end
Solution 3 - Ruby on-Rails
data = params[:image_text]# code like this data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAABPUAAAI9CAYAAABSTE0XAAAgAElEQVR4Xuy9SXPjytKm6ZwnUbNyHs7Jc7/VV9bW1WXWi9q
image_data = Base64.decode64(data['data:image/png;base64,'.length .. -1])
new_file=File.new("somefilename.png", 'wb')
new_file.write(image_data)
After you can use image as a file Photo.new(image: image)#save using paperclip in Photo model
Solution 4 - Ruby on-Rails
If you need to write it to an image then use imagemagick through the rmagick gem.