nested forms - how to use before/after destroy callback ?

[Javix]

How is it possible to use a callback and which one to avoid the destroying of the last association.

For example, there are 3 following models:

#timesheet.rb

class Timesheet < ActiveRecord::Base

  has_many :activities, dependent: :destroy

  has_many :time_entries, through: :activities

  accepts_nested_attributes_for :activities, allow_destroy: true

end

#activity.rb

class Activity < ActiveRecord::Base

  has_many :time_entries, order: :workdate, dependent: :destroy

  accepts_nested_attributes_for :time_entries, allow_destroy: true, reject_if: proc { |a| a[:worktime].blank? }

end

#time_entry.rb

class TimeEntry < ActiveRecord::Base

  belongs_to :activity

  validates :worktime, presence: true, inclusion: { in: [0.5, 1] } 

end

Every timesheet is created for 7 days (tile_entries) for one activity in the the same form. To delete I use the technic with jQuery explained at Railscats:

#add_remove_fields.js

function remove_fields(link) {

  $(link).prev("input[type=hidden]").val("1");

  $(link).closest(".fields").hide();

}

function add_fields(link, association, content) {

  var new_id = new Date().getTime();

  var regexp = new RegExp("new_" + association, "g");

  $(link).parent().before(content.replace(regexp, new_id));

}

#application_helper.rb

def link_to_remove_fields(name, f)

    f.hidden_field(:_destroy) + link_to_function(name, "remove_fields(this)")

  end

  def link_to_add_fields(name, f, association, timesheet)

...

end

I tried several ways with after_destroy hook, - it didn't work.

Any idea ? Thanks and regards.

[Javix]

So still no idea how to avoid the destroy of the last association. I do all the processing in the 'update ' action of TimesheetsController. I tried with 'after_update' hook in the Timsheet model as follows:

#timesheet.rb
class Timesheet < ActiveRecord::Base

  accepts_nested_attributes_for :activities, allow_destroy: true
  after_update :check_an_activity_present

  private
    def check_an_activity_present     
      raise "You should have at least ONE activity present" if activities.empty?
    end
end

An I put the update_attributes in the begin/rescue block in the controller:
#timesheets_controller.rb
class TimesheetsController < ApplicationController
def update
    begin
      @timesheet = current_user.timesheets.find(params[:id])         
      if @timesheet.update_attributes(params[:timesheet])
        flash[:success] = 'Timesheet updated sucessfully'
        redirect_to @timesheet
      else
        load_entries
        render 'edit'
      end
    rescue Exception => e
      flash.now[:error] = e.message
      @entries = @timesheet.time_entries
      render 'edit'
    end
   
private
  def load_entries
      @entries = @timesheet.build_and_sort_time_entries
    end   
  end
end

The problem is that the activity with corresponding time entries collection is not destroyed even if I added a new activity with corresponding time entries. So after the update executed, I have 2 activities saved with corresponding time entries instad of having just the ONLY one, entered just after the destroying the previous one. Any idea? Thank you.

[Javix]

Finally, after_update callback works as needed, te problem was in the new fields_for generation. The below is the correct and updated version:

#timesheet.rb

class Timesheet < ActiveRecord::Base

  has_many :activities, dependent: :destroy

  has_many :time_entries, through: :activities

  accepts_nested_attributes_for :activities, allow_destroy: true

end

#activity.rb

class Activity < ActiveRecord::Base

  has_many :time_entries, order: :workdate, dependent: :destroy

  accepts_nested_attributes_for :time_entries, allow_destroy: true, reject_if: proc { |a| a[:worktime].blank? }

    validate :one_time_entry_present

private

    def one_time_entry_present

      errors[:base] << "At least one entry should be entered" if time_entries.empty?

    end 

end

#time_entry.rb

class TimeEntry < ActiveRecord::Base

  belongs_to :activity

  validates :worktime, presence: true, inclusion: { in: [0.5, 1] } 

end

Every timesheet is created for 7 days (tile_entries) for one activity in the the same form. To delete I use the technic with jQuery explained at Railscats:

#add_remove_fields.js

function remove_fields(link) {

  $(link).prev("input[type=hidden]").val("1");

  $(link).closest('table').find("tr.entry_header").hide();

  $(link).closest(".fields").hide();

}

function add_fields(link, association_id, content) {

  var new_id = new Date().getTime();

  var regexp = new RegExp(association_id, "g");

  $(link).parent().before(content.replace(regexp, new_id));

}

#application_helper.rb

def link_to_remove_fields(name, f)

    f.hidden_field(:_destroy) + link_to_function(name, "remove_fields(this)")

  end

 def link_to_add_fields(name, f, association, timesheet)

    new_object = f.object.send(association).klass.new

    id = new_object.object_id    

    timesheet.create_activity_days(new_object)

    

    fields = f.fields_for(association, new_object, child_index: id) do |builder|

      render(association.to_s.singularize + "_fields", f: builder)

    end    

                    

    link_to_function(name, "add_fields(this, \"#{id}\", \"#{escape_javascript(fields)}\")")

  end

#timesheets_controller.rb

def update

    begin

      @timesheet = current_user.timesheets.find(params[:id])          

      if @timesheet.update_attributes(params[:timesheet])

        flash[:success] = 'Timesheet updated sucessfully'

        redirect_to @timesheet

      else

        load_entries

        render 'edit'

      end

    rescue Exception => e

      flash[:error] = e.message

      redirect_to edit_timesheet_path(@timesheet)

    end

    

  end

Hope this helps.