Question

Using devise, rails 3.2. I’m trying to figure out how to create an array of ids and then check if the current_user’s id is included in this array.

My users have many locations through location_users. (Locations have many users through the same relationship.)

I can get a list of user_ids associated with a location without problem:

 @location.users.each do |u|
   puts u.id

However, I assume I need to output the ids to an array and check with something like this:

  - [user_ids].include? current_user.id

How can I go about achieving this?

Answer 1

@location.users.map(&:id).include? current_user.id

or rather just

@location.users.include? current_user

should work, but involves loading all location.users and then searching through the array. I would consider writing a statements that lets the database handle this.

update: here’s a way how you can let the db handle it say you want to check if user 5 is in location 1:

LocationsUser.where(location_id: 1).find_by_user_id(5)

this returns either the association (instance of LocationsUser) or nil.