The Ruby Way: Solutions and Techniques in Ruby Programming, Second Edition

2.37. Encoding and Decoding base64 Strings

base64 is frequently used to convert machine-readable data into a text form with no special characters in it. For example, newsgroups that handle binary files such as program executables frequently will use base64.

The easiest way to do a base64 encode/decode is to use the built-in features of Ruby. The Array class has a pack method that returns a base64 string (given the parameter “m”). The String class has a method unpack that likewise unpacks the string (decoding the base64):

str = "\007\007\002\abdce"

new_string = [str].pack("m")         # "BwcCB2JkY2U="
original   =  new_string.unpack("m") # ["\a\a\002\abdce"]

Note that an array is returned by unpack.