Generating GUIDs in Ruby

user_17174 0
Viewed 102313

I have a 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 uuid gem @ rubyforge 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 ...

guid ruby
11 Answers

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"
user_5167610

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"
user_1235270

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.

Andrew_Hare_342110

This is a neet technique I learnt from JavaScript:

def uuid
    "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx".gsub("x") do
        "0123456789ABCDEF"[rand(16)]
    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
user_63021310
user_6776840

For rails running a postgreSQL database do 2 things.

Step 1: generate a scaffold/model

rails g scaffold manager name:string --primary-key-type=uuid

Step 2: Add a line to migration file

If you rails db:migrate now, you'll get a PG::UndefinedFunction: ERROR: function gen_random_uuid() does not exist error.

So add this to the migration file

enable_extension 'pgcrypto' unless extension_enabled?('pgcrypto')

Example:

class CreateManagers < ActiveRecord::Migration[7.0]

  enable_extension 'pgcrypto' unless extension_enabled?('pgcrypto')

  def change
    create_table :managers, id: :uuid do |t|
      t.string :name
      t.timestamps
    end
  end
end

You're done!

Oh one last thing, you only nee to add enable_extension 'pgcrypto' unless extension_enabled?('pgcrypto') to one migration file (e.g. the first time you use uuid type).

user_57837450
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