如何将Base 64图像上传到Rails回形针

Question

I've tried a million different tutorials on the internet for how to upload a Base64 image from my iOS application to my rails app. It seems that no matter how I format the request it just won't get accepted.

Does anyone know definitively how to upload a Base64 image to paperclip?

I tried sending the param as JSON

{ "thumbnail_image": "base64_data..." }

I also tried appending the data url

{ "thumbnail_image": "data:image/jpeg;base64,alkwdjlaks..." }

I tried sending a JSON object with and without data url

{ "thumbnail_image": { "filename": "thumbnail.jpg", "file_data": "base64_data...", "content_type": "image/jpeg" } }

I consistently get these Paperclip::NoHandlerError s and then it dumps a giant blob of data into my log.

Answer 1

Your Base64 string seems to be fine. You can always check that here

So the problem is probably on the Rails side. Check that the string you receive is exactly the same like the one you are sending.

With Paperclip 4.2.1 I managed to save Base64 GIF file that way:

Having:

class Thing
    has_attached_file :image

and POST attributes:

{
    "thumbnail_data:" "data:image/gif;base64,iVBORw0KGgo..."
}

All you have to do is to find proper adapter and specify original_filename. So for controller that would be:

def create
    image = Paperclip.io_adapters.for(params[:thumbnail_data]) 
    image.original_filename = "something.gif"
    Thing.create!(image: image)
    ...
end

AFAIK Paperclip made it easier to save base64 from version 3.5.0.

Hope that helps!

Answer 2

This is how I have done it in the past and it is basically a brute force approach, not sure if paperclip has added better support in recent versions, but this should work

class FooBar < ActiveRecord::Base
  has_attached_file :thumbnail_image
  validates_attachment_content_type :thumbnail_image,
                                     content_type: %w(image/jpeg image/jpg image/png image/gif),
                                     message: "is not gif, png, jpg, or jpeg." 

  attr_accessor :base64_thumbnail_image

  # call this explicitly from the controller or in an after_save callback
  # after setting the base64_thumbnail_image attribute
  def save_base64_thumbnail_image
    if base64_thumbnail_image.present?
      file_path = "tmp/foo_bar_thumbnail_image_#{self.id}.png"
      File.open(file_path, 'wb') { |f| f.write(Base64.decode64(base64_thumbnail_image)) }
      # set the paperclip attribute and let it do its thing
      self.thumbnail_image = File.new(file_path, 'r')
    end
  end  
end

# params should be base64_thumbnail_image, not thumbnail_image in this case