Webservice to convert file to base64 string

Is there a webservice available that will take a url of a file e.g. http://example.com/images/image.jpg and return a base64 enc开发者_Go百科oded string of that file preferably in json format?

Where are you trying to use this from? Would something like this work?

curl http://example.com/images/image.jpg | base64