How to invoke a method in controller? - ruby-on-rails

Question

I had the following code in my create action.
tasks_comtroller.rb
def create
#task = current_user.tasks.build(task_params)
#task.complete = false
n=1
loop do
unless Task.find_by priority: n
#task.priority=n
break
end
n+=1
end
respond_to do |format|
if #task.save
format.html { redirect_to user_tasks_path(current_user) }
format.js
else
format.html { render action: 'new' }
format.js
end
end
end
Then I took out some part I made a method inside my task model.
class Task < ActiveRecord::Base
def priority_increment
n=1
loop do
unless Task.find_by priority: n
#task.priority=n
break
end
n+=1
end
end
end
How can I now correctly invoke this method from controller?

Answer 1

Thats really inefficient since each iteration has to do a database query - instead do Task.order(:priority).first and let the database do the work.
class Task < ActiveRecord::Base
def self.heighest_priority
# .try lets us handle the case where there
# are no Tasks gracefully
p = Task.order(:priority).first.try(:priority)
# return the highest + 1 or 1 if there are no tasks.
p ? p + 1 : 1
end
end
Calling methods in ruby in exactly the same no matter where you are calling the function:
obj.some_method # in Ruby the parens are optional
obj.some_method(someArg)
obj.some_method(someArg) do
# blocks are awesome.
end
Here we have a class method - we call it by Task.heighest_priority.
So lets refactor the create method to use our new method:
def create
#task = current_user.tasks.build(task_params) do |t|
t.priority = Task.heighest_priority
t.complete = false
end
if #task.save
format.html { redirect_to user_tasks_path(current_user) }
format.js
else
format.html { render action: 'new' }
format.js
end
end

Answer 2

If you want to put that part of code into the model, you have to call self instead of the instance variable #task like so:
class Task < ActiveRecord::Base
def priority_increment
n=1
loop do
unless Task.find_by priority: n
self.priority=n
break
end
n+=1
end
end
end
Afterwards you can call it on the task instance:
#task.priority_increment