Base64 encode with no padding on ruby 2.2

Question

I'm attempting to base64 encode some things in ruby 2.2 (environment limitation) without padding. I know that in ruby 2.3 the base64 library added a padding flag that can do this for me. However, when I attempt to do this myself in ruby 2.2 using

Base64.urlsafe_encode464(str).gsub('=', '')

This creates issues for me when decoding however. Is there a way to update to the latest base64 library while staying on ruby 2.2? Or is there a good way to do a urlsafe base64 encoding that will decode correctly?

Answer 1

MRI Ruby versions < 2.3.x do not support decoding Base64 content without padding (where the encoded content originally had it).

The following Ruby bug report shows the history of a change to support removal of padding and decoding without it for Ruby 2.3 and beyond. However if you try to use the 'padding' arg that was added in an older version of Ruby it fails with an ArgumentError. This makes it hard to support no-padding encode/decode across older and newer Rubies.

https://bugs.ruby-lang.org/issues/10740

A nice solution I found is the 'base64url' gem which works across Ruby versions and automatically removes and re-adds padding as needed on encode/decode. Its lightweight and only has about 11 lines of code.

https://github.com/nojima/base64url