rails update method not calling class methods - ruby-on-rails

Question

I have a class method that I need to call on a controller update method called auto_assign!
It essentially finds the artist with the lowest amount of requests and assigns that artist id to the object.
It works perfectly on the create method, but it does not get called on the update method, and I am not sure why.
Controller
def update
#virtual_request = VirtualRequest.find(params[:id])
#virtual_request.auto_assign! # this never gets called
if #virtual_request.update_attributes(virtual_params)
flash[:success] = "Virtual request updated"
redirect_to virtual_request_path(#virtual_request)
else
render 'edit'
end
end
def create
#virtual_request = VirtualRequest.new(virtual_params)
#virtual_request.auto_assign! # works fine here!
if #virtual_request.save
flash[:success] = "Virtual has been created and assigned to # {#virtual_request.artist.name}"
redirect_to virtual_requests_path
else
render 'new'
end
end
Class VirtualRequest
def auto_assign!
if self.artist_id == 0
artists = Artist.in_queue?.collect {|p| [ p.id, p.virtual_requests.count ] }
self.artist_id = artists.sort { |a,b| a[1] <=> b[1] }.first[0]
end
end
HTML sending parameters
<select id="virtual_request_artist_id" name="virtual_request[artist_id]">
<option selected="selected" value="0">auto-assign</option>
<option value="2">Artist 1</option>
<option value="5">Artist 2</option>
</select>
it is supposed to auto-assign when the value in the params is 0
UPDATE: solved
Controller
def update
#virtual_request = VirtualRequest.find(params[:id])
if #virtual_request.update_attributes(virtual_params)
#virtual_request.auto_assign!
flash[:success] = "Virtual request updated"
redirect_to virtual_request_path(#virtual_request)
else
render 'edit'
end
end
Class
def auto_assign!
if self.artist_id == 0
artists = Artist.in_queue?.collect {|p| [ p.id, p.virtual_requests.count ] }
self.artist_id = artists.sort { |a,b| a[1] <=> b[1] }.first[0]
self.save
end
end

Answer 1

A couple of things are wrong:
First you need to call the #virtual_request.auto_assign! within the conditional because artist_id would not have been set otherwise.
Secondly don't forget to save the updated instance when you make the changes in the auto_assign method so:
def update
#virtual_request = VirtualRequest.find(params[:id])
if #virtual_request.update(virtual_params)
#virtual_request.auto_assign!
#virtual_request.save
flash[:success] = "Virtual request updated"
redirect_to virtual_request_path(#virtual_request)
else
render 'edit'
end
end
something on these lines but I'm sure others will suggest a more efficient solution
alternatively for your method (you won't need the save in your Controller with this approach).
def auto_assign!
if self.artist_id == 0
artists = Artist.in_queue?.collect {|p| [ p.id, p.virtual_requests.count ] }
artist_id = artists.sort { |a,b| a[1] <=> b[1] }.first[0]
self.update_attribute(:artist_id,artist_id)
end
end
a few things to play with anyway!