Generating unique random string for identifying a record

Question

I have a requirement to be able to identify a record in a table, in this case a user table, by a unique key which does not give away the ordering of the records in the table.

Currently I have primary key field and the routes that are generated look like:

/users/1

However, I'd like to be able to generate a route like:

/users/kfjslncdk

I can wire everything up on the route side, database side etc.. but I'm not sure what the best way to generate a unique string identifier would be in rails. I'd like do something like:

before_save :create_unique_identifier

def create_unique_identifier
    self.unique_identifier = ... magic goes here ...
end

I was thinking I could use the first part of a guid created using UUIDTools, but I'd need to check to make sure it was unique before saving the user.

Any advice would be greatly appreciated!

Steven Evers · Accepted Answer · 2018-02-04 09:36:24Z

59

before_create :create_unique_identifier

def create_unique_identifier
  loop do
    self. unique_identifier = SecureRandom.hex(5) # or whatever you chose like UUID tools
    break unless self.class.exists?(:unique_identifier => unique_identifier)
  end
end

edited Feb 4, 2018 at 9:36

Steven Evers

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answered Nov 12, 2012 at 8:21

Aditya Sanghi

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Comments

NARKOZ · Accepted Answer · 2012-11-12 08:10:47Z

10

Ruby 1.9 includes a built-in UUID generator: SecureRandom.uuid

answered Nov 12, 2012 at 8:10

NARKOZ

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Comments

Benjamin Carlsson · Accepted Answer · 2019-05-08 07:09:14Z

5

edited May 8, 2019 at 7:09

Benjamin Carlsson

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answered Nov 29, 2009 at 0:41

Simone Carletti

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1 Comment

Abel Over a year ago

I believe UUID was already known by the asker (see the q. text) ;). But +1 for the third link.

Fellow Stranger · Accepted Answer · 2020-04-13 14:20:04Z

5

Another possiblity is to use SecureRandom.base64 which in comparison to hex additionally use capitalized letters and “+”, “/”, “=”. Documentation.

Example:

def generate_identifier
  begin
    uid = SecureRandom.base64(8)
  end while self.class.exists?(uid: uid)
  self.uid = uid
end

edited Apr 13, 2020 at 14:20

answered Apr 13, 2020 at 13:51

Fellow Stranger

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Comments

fphilipe · Accepted Answer · 2012-11-12 08:36:31Z

3

Save yourself the trouble from storing the obfuscated id and simply encode the id with base 62 (a-z, A-Z, 0-9) but custom define the order of the "digits". This will make it very complicated to figure out the order.

I once wrote something a class that does that (might need some refactoring): https://gist.github.com/4058176

answered Nov 12, 2012 at 8:36

fphilipe

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