Question

i am trying to add a unique entry on click so that a user can accept an event they have been invited to. the user should only be able to click this link once. at present i have the following code which seems to be adding the entry, though i dont think its the best practice, plus the unique id doesn’t seem to be working too well

haml

             %li= link_to 'Add', availabilities_path(:availability => {:team_id => @event.team_id, :user_id => user, :event_id => @event.id, :unique_id => availability_unique_id(user,@event) }), :remote => true, :method => :post, :class => 'button tiny success'

model

validates :unique_id, :presence => true, :uniqueness => true

unique method

def availability_unique_id(player,schedule)
    Base64.encode64("#{player.to_s}_#{schedule.id.to_s}_#{schedule.team.id.to_s}")
  end

as you can see from the query below the unique value isn’t being looked out

select * from availabilities where user_id = 41;
 id | available | user_id | team_id | event_id |         created_at         |         updated_at         |            unique_id             | comment 
----+-----------+---------+---------+----------+----------------------------+----------------------------+----------------------------------+---------
 61 |           |      41 |         |          | 2012-11-04 13:48:22.794214 | 2012-11-04 13:48:22.794214 | NDFfNDNfMQ==                    +| 
    |           |         |         |          |                            |                            |                                  | 
 84 |           |      41 |       1 |       75 | 2013-02-09 14:03:29.792374 | 2013-02-09 14:03:29.792374 | IzxVc2VyOjB4YWY3NTMxND5fNzVfMQ==+| 
    |           |         |         |          |                            |                            |                                  | 
 85 |           |      41 |       1 |       75 | 2013-02-09 14:06:04.131862 | 2013-02-09 14:06:04.131862 | IzxVc2VyOjB4YjJhODBiOD5fNzVfMQ==+| 
    |           |         |         |          |                            |                            |                                  | 
 87 |           |      41 |       1 |       75 | 2013-02-09 14:07:31.77788  | 2013-02-09 14:07:31.77788  | IzxVc2VyOjB4YjBhYjdiMD5fNzVfMQ==+| 
    |           |         |         |          |                            |                            |                                  | 

Answer 1

from the comments. the validation below makes sure that you have a unique user_id for each event_id. you can add multiple scopes if needed.

validates :user_id, uniqueness: { scope: :event_id }