Converting an Uploaded File to a string while maintaining binary data

Ok so it boils down to this I uploaded a picture into a ActionDispatch::Http::UploadedFile and want to convert it to a string before I send it off google storage. When I do this it complains about having null characters.

I had the same problem when I was experimenting with files from my hard drive with the same function. I was able to do it with: 'filename', 'rb' )

but I don't know how do read an ActionDispatch::Http::UploadedFile as a binary. Does any one know how to do this? Thank you.