before_filter with parameters

Solution 1:

I'd do it like this:

before_filter { |c| c.authenticate_rights correct_id_here }

def authenticate_rights(project_id)
  project = Project.find(project_id)
  redirect_to signin_path unless project.hidden
end

Where correct_id_here is the relevant id to access a Project.

Solution 2:

With some syntactic sugar:

before_filter -> { find_campaign params[:id] }, only: [:show, :edit, :update, :destroy]

Or if you decide to get even more fancy:

before_filter ->(param=params[:id]) { find_campaign param }, only: %i|show edit update destroy|

And since Rails 4 before_action, a synonym to before_filter, was introduced, so it can be written as:

before_action ->(param=params[:id]) { find_campaign param }, only: %i|show edit update destroy|

NB

-> stands for lambda, called lambda literal, introduce in Ruby 1.9

%i will create an array of symbols

Solution 3:

To continue @alex' answer, if you want to :except or :only some methods, here is the syntax:

before_filter :only => [:edit, :update, :destroy] do |c| c.authenticate_rights params[:id] end 

Found here.

Solution 4:

I find the block method using curly braces instead of do...end to be the clearest option

before_action(only: [:show]) { authenticate_rights(id) }

before_action is just the newer preferred syntax for before_filter