encoding and decoding in Ruby using Base64 Module
By: Emiley J.
The Base64 module provides for the encoding (encode64) and decoding (decode64) of binary data using a Base64 representation.
The following particular features are also provided:
- encode into lines of a given length (b64encode)
- decode the special format specified in RFC2047 for the representation of email headers (decode_b)
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. It is specified in RFC 2045 (www.faqs.org/rfcs/rfc2045.html).
b64encode(bin, len = 60)Prints the Base64 encoded version of bin (a String) in lines of len (default 60) characters.
require 'base64' data = "Now is the time for all good coders\nto learn Ruby" puts Base64.b64encode(data)
Generates:
Tm93IGlzIHRoZSB0aW1lIGZvciBhbGwgZ29vZCBjb2RlcnMKdG8gbGVhcm4g UnVieQ==
# File base64.rb, line 112 def b64encode(bin, len = 60) encode64(bin).scan(/.{1,#{len}}/o) do print $&, "\n" end enddecode64(str)
Returns the Base64-decoded version of str.
require 'base64' str = 'VGhpcyBpcyBsaW5lIG9uZQpUaGlzIG' + 'lzIGxpbmUgdHdvClRoaXMgaXMgbGlu' + 'ZSB0aHJlZQpBbmQgc28gb24uLi4K' puts Base64.decode64(str)
Generates:
This is line one This is line two This is line three And so on...
# File base64.rb, line 58 def decode64(str) str.unpack("m")[0] enddecode_b(str)
Decodes text formatted using a subset of RFC2047 (the one used for mime-encoding mail headers).
Only supports an encoding type of ‘b’ (base 64), and only supports the character sets ISO-2022-JP and SHIFT_JIS (so the only two encoded word sequences recognized are =?ISO-2022-JP?B?…= and =?SHIFT_JIS?B?…=). Recognition of these sequences is case insensitive.
# File base64.rb, line 72 def decode_b(str) str.gsub!(/=\?ISO-2022-JP\?B\?([!->@-~]+)\?=/i) { decode64($1) } str = Kconv::toeuc(str) str.gsub!(/=\?SHIFT_JIS\?B\?([!->@-~]+)\?=/i) { decode64($1) } str = Kconv::toeuc(str) str.gsub!(/\n/, ' ') str.gsub!(/\0/, '') str endencode64(bin)
Returns the Base64-encoded version of str.
require 'base64' Base64.b64encode("Now is the time for all good coders\nto learn Ruby")
Generates:
Tm93IGlzIHRoZSB0aW1lIGZvciBhbGwgZ29vZCBjb2RlcnMKdG8gbGVhcm4g UnVieQ==
# File base64.rb, line 96 def encode64(bin) [bin].pack("m") end
Archived Comments
1. Please check this article
<a href="/blog/2011/08/how-to-encode-and-decode-in-
View Tutorial By: imby at 2011-10-12 17:14:59
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