# frozen_string_literal: true # # = base64.rb: methods for base64-encoding and -decoding strings # # The Base64 module provides for the encoding (#encode64, #strict_encode64, # #urlsafe_encode64) and decoding (#decode64, #strict_decode64, # #urlsafe_decode64) of binary data using a Base64 representation. # # == Example # # A simple encoding and decoding. # # require "base64" # # enc = Base64.encode64('Send reinforcements') # # -> "U2VuZCByZWluZm9yY2VtZW50cw==\n" # plain = Base64.decode64(enc) # # -> "Send reinforcements" # # The purpose of using base64 to encode data is that it translates any # binary data into purely printable characters. module Base64 module_function # Returns the Base64-encoded version of +bin+. # This method complies with RFC 2045. # Line feeds are added to every 60 encoded characters. # # require 'base64' # Base64.encode64("Now is the time for all good coders\nto learn Ruby") # # <i>Generates:</i> # # Tm93IGlzIHRoZSB0aW1lIGZvciBhbGwgZ29vZCBjb2RlcnMKdG8gbGVhcm4g # UnVieQ== def encode64(bin) [bin].pack("m") end # Returns the Base64-decoded version of +str+. # This method complies with RFC 2045. # Characters outside the base alphabet are ignored. # # require 'base64' # str = 'VGhpcyBpcyBsaW5lIG9uZQpUaGlzIG' + # 'lzIGxpbmUgdHdvClRoaXMgaXMgbGlu' + # 'ZSB0aHJlZQpBbmQgc28gb24uLi4K' # puts Base64.decode64(str) # # <i>Generates:</i> # # This is line one # This is line two # This is line three # And so on... def decode64(str) str.unpack1("m") end # Returns the Base64-encoded version of +bin+. # This method complies with RFC 4648. # No line feeds are added. def strict_encode64(bin) [bin].pack("m0") end # Returns the Base64-decoded version of +str+. # This method complies with RFC 4648. # ArgumentError is raised if +str+ is incorrectly padded or contains # non-alphabet characters. Note that CR or LF are also rejected. def strict_decode64(str) str.unpack1("m0") end # Returns the Base64-encoded version of +bin+. # This method complies with ``Base 64 Encoding with URL and Filename Safe # Alphabet'' in RFC 4648. # The alphabet uses '-' instead of '+' and '_' instead of '/'. # Note that the result can still contain '='. # You can remove the padding by setting +padding+ as false. def urlsafe_encode64(bin, padding: true) str = strict_encode64(bin) str.tr!("+/", "-_") str.delete!("=") unless padding str end # Returns the Base64-decoded version of +str+. # This method complies with ``Base 64 Encoding with URL and Filename Safe # Alphabet'' in RFC 4648. # The alphabet uses '-' instead of '+' and '_' instead of '/'. # # The padding character is optional. # This method accepts both correctly-padded and unpadded input. # Note that it still rejects incorrectly-padded input. def urlsafe_decode64(str) # NOTE: RFC 4648 does say nothing about unpadded input, but says that # "the excess pad characters MAY also be ignored", so it is inferred that # unpadded input is also acceptable. str = str.tr("-_", "+/") if !str.end_with?("=") && str.length % 4 != 0 str = str.ljust((str.length + 3) & ~3, "=") end strict_decode64(str) end end