Methods

Class Public methods

uuid_from_hash(hash_class, uuid_namespace, name)

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

Using Digest::MD5 generates version 3 UUIDs; 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

📝 Source code 
# File activesupport/lib/active_support/core_ext/digest/uuid.rb, line 19
    def self.uuid_from_hash(hash_class, uuid_namespace, name)
      if hash_class == Digest::MD5
        version = 3
      elsif hash_class == Digest::SHA1
        version = 5
      else
        raise ArgumentError, "Expected Digest::SHA1 or Digest::MD5, got #{hash_class.name}."
      end

      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
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uuid_v3(uuid_namespace, name)

Convenience method for uuid_from_hash using Digest::MD5.

📝 Source code 
# File activesupport/lib/active_support/core_ext/digest/uuid.rb, line 40
    def self.uuid_v3(uuid_namespace, name)
      uuid_from_hash(Digest::MD5, uuid_namespace, name)
    end
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uuid_v4()

Convenience method for SecureRandom.uuid.

📝 Source code 
# File activesupport/lib/active_support/core_ext/digest/uuid.rb, line 50
    def self.uuid_v4
      SecureRandom.uuid
    end
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uuid_v5(uuid_namespace, name)

Convenience method for uuid_from_hash using Digest::SHA1.

📝 Source code 
# File activesupport/lib/active_support/core_ext/digest/uuid.rb, line 45
    def self.uuid_v5(uuid_namespace, name)
      uuid_from_hash(Digest::SHA1, uuid_namespace, name)
    end
🔎 See on GitHub