123456789_123456789_123456789_123456789_123456789_

Module: Digest::UUID

Relationships & Source Files
Defined in: activesupport/lib/active_support/core_ext/digest/uuid.rb

Class Method Summary

Class Method Details

.nil_uuid

Returns the nil UUID. This is a special form of UUID that is specified to have all 128 bits set to zero.

[ GitHub ] 

  


# File 'activesupport/lib/active_support/core_ext/digest/uuid.rb', line 58



def self.nil_uuid
  "00000000-0000-0000-0000-000000000000"
end


  








  

    .uuid_from_hash(hash_class, namespace, name)  
  



  

    

Generates a v5 non-random UUID (Universally Unique IDentifier).



Using OpenSSL::Digest::MD5 generates version 3 UUIDs; OpenSSL::Digest::SHA1 generates version 5 UUIDs. uuid_from_hash always generates the same UUID for a given name and namespace combination.



See RFC 4122 for details of UUID at: www.ietf.org/rfc/rfc4122.txt


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/core_ext/digest/uuid.rb', line 19



def self.uuid_from_hash(hash_class, namespace, name)
  if hash_class == Digest::MD5 || hash_class == OpenSSL::Digest::MD5
    version = 3
  elsif hash_class == Digest::SHA1 || hash_class == OpenSSL::Digest::SHA1
    version = 5
  else
    raise ArgumentError, "Expected OpenSSL::Digest::SHA1 or OpenSSL::Digest::MD5, got #{hash_class.name}."
  end

  uuid_namespace = pack_uuid_namespace(namespace)

  hash = hash_class.new
  hash.update(uuid_namespace)
  hash.update(name)

  ary = hash.digest.unpack("NnnnnN")
  ary[2] = (ary[2] & 0x0FFF) | (version << 12)
  ary[3] = (ary[3] & 0x3FFF) | 0x8000

  "%08x-%04x-%04x-%04x-%04x%08x" % ary
end


  








  

    .uuid_v3(uuid_namespace, name)  
  



  

    

Convenience method for uuid_from_hash using OpenSSL::Digest::MD5.


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/core_ext/digest/uuid.rb', line 42



def self.uuid_v3(uuid_namespace, name)
  uuid_from_hash(OpenSSL::Digest::MD5, uuid_namespace, name)
end


  








  

    .uuid_v4  
  



  

    

Convenience method for SecureRandom.uuid.


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/core_ext/digest/uuid.rb', line 52



def self.uuid_v4
  SecureRandom.uuid
end


  








  

    .uuid_v5(uuid_namespace, name)  
  



  

    

Convenience method for uuid_from_hash using OpenSSL::Digest::SHA1.


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/core_ext/digest/uuid.rb', line 47



def self.uuid_v5(uuid_namespace, name)
  uuid_from_hash(OpenSSL::Digest::SHA1, uuid_namespace, name)
end