I have the following code in a controller action, which looks at a user, and changes a boolean value to the opposite value, so if the user is true then it becomes false, and vice versa:
if current_user.enable_access
current_user.update_attribute(:enable_access, false)
else
current_user.update_attribute(:enable_access, true)
end
Is there a neater way of writing this?
How about using the toggle method that was specifically intended for this?
current_user.toggle(:enable_access)
If you want to add persistence in one character, there's also the toggle! method.
current_user.toggle!(:enable_access)
toggle won’t save a record, while update_attribute does. toggle! is just a syntactic sugar, but yes, it is :)In one line, if current_user.enable_access can be only true`false`:
current_user.update_attribute(:enable_access, !current_user.enable_access)
current_user.update_attribute(:enable_access, !current_user.enable_access) (note the !)
Here's something to meditate on:
false # => false
true # => true
!false # => true
!true # => false
foo = false # => false
!foo # => true
foo = !foo # => true
foo = nil # => nil
!foo # => true
foo = !nil # => true
foo = !false # => true
Notice !!, which is a convenient way to turn a value into a true/false:
foo = !!nil # => false
foo = !!false # => false
foo = 1 # => 1
!foo # => false
!!foo # => true
foo = 'a' # => "a"
!foo # => false
!!foo # => true
0 == 1 # => false
1 == 1 # => true
'a' == '' # => false
'a' == 'a' # => true
These are the building blocks for comparisons in Ruby.
While the answer by @Зеленый is absolutely correct I wondered, that there is no DRY way to accomplish such a silly task.
The problem is that true and false in Ruby are instances of different classes, TrueClass and FalseClass respectively. That said, one can not just switch the boolean value inplace.
But what we can imagine, mediating at update_attribute source? Probably this is a shortest way to accomplish your task (please, do not use it at home, it’s a joke after all.)
current_user.tap do |cu|
cu.enable_access ^= true
end.save validate: false
I just reinvented toggle!, thanks @Dremni for pointing this out.
current_user.toggle!(:enable_access)
http://api.rubyonrails.org/classes/ActiveRecord/Persistence.html#method-i-toggle-21
I believe the DRY way to accomplish it would be to use:
current_user.enable_access = !current_user.enable_access
Then you could just write a method on a model and call it from any controller.
user.rb
def enable_user_access
self.enable_access = !self.enable_access
end
then calling it from a controller
current_user.enable_user_access
