Generating Guids in Ruby

Question

I have problem that is really easily solved with Guids.

In particular, for a password reset workflow, I would like to send a Guid token to a user's email and have them reset their password using the token. Since guids are unique, this is pretty secure and saves me emailing people passwords, which is risky.

I noticed there is one Guid gem for Ruby; but it looks quite old, and it writes stuff to the file system.

Does anyone know of any other gems that can create a globally unique identifier?

I know I can just fall back to:

(0..16).to_a.map{|a| rand(16).to_s(16)}.join 

But it does not really seem like a proper GUID ...

Answer 1

As of Ruby 1.9, uuid generation is built-in. Use the SecureRandom.uuid function.

For example:

require 'securerandom'
SecureRandom.uuid # => "96b0a57c-d9ae-453f-b56f-3b154eb10cda"

Answer 2

We use UUIDTools and have no problems with it.

Answer 3

How to create small, unique tokens in Ruby

>> require 'digest'
=> []
>> Digest::SHA1.hexdigest("some-random-string")[8..16]
=> "2ebe5597f"

>> SecureRandom.base64(8).gsub("/","_").gsub(/=+$/,"")
=> "AEWQyovNFo0" 

>> rand(36**8).to_s(36)
=> "uur0cj2h"

Answer 4

Did you look at UUIDTools?

UUIDTools was designed to be a simple library for generating any of the various types of UUIDs (or GUIDs if you prefer to call them that). It conforms to RFC 4122 whenever possible.

Answer 5

Google yields the following Ruby library:

http://raa.ruby-lang.org/project/ruby-guid/

Also, over at http://www.ruby-forum.com/topic/99262 they say you can install a gem (execute gem uuid on the command line to install it) and then do

gem 'uuid'
puts UUID.new

in your code to see a new UUID.

(Hint: I Googled for guid ruby)

Answer 6

Small update to Simone Carletti answer:

SecureRandom.base64(8).gsub("/","_").gsub(/=+$/,"")

=> "AEWQyovNFo0"

can be replaced with:

SecureRandom.urlsafe_base64(8)

Answer 7

To create a proper, mysql, varchar 32 GUID

SecureRandom.uuid.gsub('-','').upcase

Answer 8

While programming late at night I came up with the following solution (based off Simone's) for generating a unique GUID in Rails. I am not proud of it but it does work quite well.

while Order.find_by_guid(guid = rand(36**8).to_s(36).upcase).present?; end

Answer 9

When I used uuid gems recommended in this question, no one can generate unique and random UUID. My answer is a work around, if we have gem later to satisfy the request, you'd better to use gem in Ruby.

I try most recommended uuid gems in this question, but no one make me satisfied, we need unique and random uuid. I directly run system command uuidgen in ruby, and I like the result, and share here.

puts `uuidgen`
8adea17d-b918-43e0-b82f-f81b3029f688
puts `uuidgen`
6a4adcce-8f64-41eb-bd7e-e65ee6d11231
puts `uuidgen`
51d5348b-8fc3-4c44-a6f7-9a8588d7f08a
puts `uuidgen`
332a0fa3-7b07-41e1-9fc8-ef804a377e4e

if compare with uuid gem, you will know the difference.

irb(main):003:0> uuid.generate
=> "40cdf890-ebf5-0132-2250-20c9d088be77"
irb(main):004:0> uuid.generate
=> "4161ac40-ebf5-0132-2250-20c9d088be77"

Test environment is linux and Mac OS environment.

Answer 10

This is a neet technique I learnt from JavaScript:

def uuid
    "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx".gsub("x") do
        "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"[rand(36)]
    end
end

Although in a more 'ruby way' one could also do:

def uuid
    "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx".gsub("x") do
        rand(16).to_s(16)
    end
end