DataMapper case-insensitive unique validation

Question

I have something like:

class User
  include DataMapper::Resource

  property :id, Serial
  property :username, String, :unique => true
end

post '/signup' do
  user = User.create(username: params['username'])
  if user.save
    puts "New user was created"
  else
    puts user.errors
  end
end

Parameter :unique => true is case-sensitive. It does not prevent to create users with usernames 'admin' and 'Admin'. How can I validate case-insensitive username unique, with out downcased username property, so users can make usernames as they choose.

Patrick Oscity · Accepted Answer · 2014-01-03T15:39:56.710

1

You can provide your own custom validation:

class User
  include DataMapper::Resource

  property :id, Serial
  property :username, String

  validates_with_method :username,
                        :method => :case_insensitive_unique_username

  def case_insensitive_unique_username
    User.first(conditions: ["username ILIKE ?", self.username]).nil?
  end
end

Note that ILIKE will only work with PostgreSQL, you will have to find out how to find records case insensitively with your specific adapter for yourself.

edited Jan 03 '14 at 15:39

answered Jan 03 '14 at 10:19

Patrick Oscity

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I use PostgreSQL and `ilike` return NoMethodError, but with `like` it work. – slowpoke Jan 03 '14 at 12:27
1

I think you need to use `ILIKE` (`LIKE` is case sensitive). I will edit my answer. – Patrick Oscity Jan 03 '14 at 12:33
Edited. Also used `first(...)` and `nil?` which should work faster because the database will return immediately after finding a single conflicting record. – Patrick Oscity Jan 03 '14 at 15:40

DataMapper case-insensitive unique validation

1 Answers1