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Module: Random::Formatter

Relationships & Source Files
Extension / Inclusion / Inheritance Descendants
Extended In:
Defined in: lib/securerandom.rb

Instance Method Summary

Instance Method Details

#base64(n = nil)

SecureRandom.base64 generates a random base64 string.

The argument n specifies the length, in bytes, of the random number to be generated. The length of the result string is about 4/3 of n.

If n is not specified or is nil, 16 is assumed. It may be larger in the future.

The result may contain A-Z, a-z, 0-9, “+”, “/” and “=”.

p SecureRandom.base64 #=> "/2BuBuLf3+WfSKyQbRcc/A=="
p SecureRandom.base64 #=> "6BbW0pxO0YENxn38HMUbcQ=="

If a secure random number generator is not available, NotImplementedError is raised.

See RFC 3548 for the definition of base64.

[ GitHub ]

  
# File 'lib/securerandom.rb', line 138

def base64(n=nil)
  [random_bytes(n)].pack("m*").delete("\n")
end

#gen_random(n) (private)

[ GitHub ]

  
# File 'lib/securerandom.rb', line 244

def gen_random(n)
  self.bytes(n)
end

#hex(n = nil)

SecureRandom.hex generates a random hexadecimal string.

The argument n specifies the length, in bytes, of the random number to be generated. The length of the resulting hexadecimal string is twice of n.

If n is not specified or is nil, 16 is assumed. It may be larger in the future.

The result may contain 0-9 and a-f.

p SecureRandom.hex #=> "eb693ec8252cd630102fd0d0fb7c3485"
p SecureRandom.hex #=> "91dc3bfb4de5b11d029d376634589b61"

If a secure random number generator is not available, NotImplementedError is raised.

[ GitHub ]

  
# File 'lib/securerandom.rb', line 117

def hex(n=nil)
  random_bytes(n).unpack("H*")[0]
end

#random_bytes(n = nil)

SecureRandom.random_bytes generates a random binary string.

The argument n specifies the length of the result string.

If n is not specified or is nil, 16 is assumed. It may be larger in future.

The result may contain any byte: “x00” - “xff”.

p SecureRandom.random_bytes #=> "\xD8\\\xE0\xF4\r\xB2\xFC*WM\xFF\x83\x18\xF45\xB6"
p SecureRandom.random_bytes #=> "m\xDC\xFC/\a\x00Uf\xB2\xB2P\xBD\xFF6S\x97"

If a secure random number generator is not available, NotImplementedError is raised.

[ GitHub ]

  
# File 'lib/securerandom.rb', line 97

def random_bytes(n=nil)
  n = n ? n.to_int : 16
  gen_random(n)
end

#urlsafe_base64(n = nil, padding = false)

SecureRandom.urlsafe_base64 generates a random URL-safe base64 string.

The argument n specifies the length, in bytes, of the random number to be generated. The length of the result string is about 4/3 of n.

If n is not specified or is nil, 16 is assumed. It may be larger in the future.

The boolean argument padding specifies the padding. If it is false or nil, padding is not generated. Otherwise padding is generated. By default, padding is not generated because “=” may be used as a URL delimiter.

The result may contain A-Z, a-z, 0-9, “-” and “_”. “=” is also used if padding is true.

p SecureRandom.urlsafe_base64 #=> "b4GOKm4pOYU_-BOXcrUGDg"
p SecureRandom.urlsafe_base64 #=> "UZLdOkzop70Ddx-IJR0ABg"

p SecureRandom.urlsafe_base64(nil, true) #=> "i0XQ-7gglIsHGV2_BNPrdQ=="
p SecureRandom.urlsafe_base64(nil, true) #=> "-M8rLhr7JEpJlqFGUMmOxg=="

If a secure random number generator is not available, NotImplementedError is raised.

See RFC 3548 for the definition of URL-safe base64.

[ GitHub ]

  
# File 'lib/securerandom.rb', line 168

def urlsafe_base64(n=nil, padding=false)
  s = [random_bytes(n)].pack("m*")
  s.delete!("\n")
  s.tr!("+/", "-_")
  s.delete!("=") unless padding
  s
end

#uuid

SecureRandom.uuid generates a random v4 UUID (Universally Unique IDentifier).

p SecureRandom.uuid #=> "2d931510-d99f-494a-8c67-87feb05e1594"
p SecureRandom.uuid #=> "bad85eb9-0713-4da7-8d36-07a8e4b00eab"
p SecureRandom.uuid #=> "62936e70-1815-439b-bf89-8492855a7e6b"

The version 4 UUID is purely random (except the version). It doesn't contain meaningful information such as MAC addresses, timestamps, etc.

The result contains 122 random bits (15.25 random bytes).

See RFC 4122 for details of UUID.

[ GitHub ]

  
# File 'lib/securerandom.rb', line 236

def uuid
  ary = random_bytes(16).unpack("NnnnnN")
  ary[2] = (ary[2] & 0x0fff) | 0x4000
  ary[3] = (ary[3] & 0x3fff) | 0x8000
  "%08x-%04x-%04x-%04x-%04x%08x" % ary
end