Rails ActiveRecord: Find All Users Except Current User

Question

I feel this should be very simple but my brain is short-circuiting on it. If I have an object representing the current user, and want to query for all users except the current user, how can I do this, taking into account that the current user can sometimes be nil?

This is what I am doing right now:

def index
  @users = User.all
  @users.delete current_user
end

What I don't like is that I am doing post-processing on the query result. Besides feeling a little wrong, I don't think this will work nicely if I convert the query over to be run with will_paginate. Any suggestions for how to do this with a query? Thanks.

Answer 1

@users = (current_user.blank? ? User.all : User.find(:all, :conditions => ["id != ?", current_user.id]))

Answer 2

What you are doing is deleting the current_user from the @users Array. This won't work since there isn't a delete method for arrays. What you probably want to do is this

def index
  @users = User.all
  @users - [current_user]
end

This will return a copy of the @users array, but with the current_user object removed (it it was contained in the array in the first place.

Note: This may not work if array subtraction is based on exact matches of objects and not the content. But it worked with strings when I tried it. Remember to enclose current_user in [] to force it into an Array.

Answer 3

Here is a shorter version:

User.all :conditions => (current_user ? ["id != ?", current_user.id] : [])

Answer 4

You can also create named_scope, e.g. in your model:

named_scope :without_user, lambda{|user| user ? {:conditions => ["id != ?", user.id]} : {} }

and in controller:

def index
  @users = User.without_user(current_user).paginate
end

This scope will return all users when called with nil and all users except given in param in other case. The advantage of this solution is that you are free to chain this call with other named scopes or will_paginate paginate method.