Question

I have class methods like these in a “message” model:

 def delete_all_users_messages(user_id, parent_id)
          message = Message.find_by_parent_id(parent_id)
          message.children.where(:sender_id => user_id ).update_all(:sender_status => 1)
          message.children.where(:recipient_id => user_id ).update_all(:recipient_status => 1 )
          thread = message.message_thread
          thread.update_attribute(:sender_status, 1) if thread.sender_id == user_id 
          thread.update_attribute(:recipient_status, 1) if thread.recipient_id == user_id 
            if thread.sender_status == 1 && thread.recipient_status == 1
            thread.delete
            Message.delete_all(:parent_id => parent_id)
            end
        end

        def delete_all_users_selected_messages(message_ids, user_id, parent_id)
          Message.where(:id => message_ids, :sender_id => user_id).update_all(:sender_status => 1)
          Message.where(:id => message_ids, :recipient_id => user_id).update_all(:recipient_status => 1)
          Message.where('id != ? AND parent_id = ?', parent_id, parent_id).where(:sender_status => 1, :recipient_status => 1).delete_all
          thread = MessageThread.find_by_message_id(parent_id)
          children_exist = thread.message.children.where('id != ? AND parent_id = ?', parent_id, parent_id).any?
            unless children_exist
              thread.delete 
              thread.message.delete
            end

I use them in my messages_controller like this:

def destroy_all_messages
    Message.delete_all_users_messages(current_user.id, params[:format])
    flash[:success] = "Messages deleted"
    redirect_to messages_path
  end


  def destroy_selected_messages
    Message.delete_all_users_selected_messages(params[:message_ids], current_user.id, params[:format])
      flash[:success] = "Messages deleted"
      redirect_to :back
  end

I would like to also return an error message if something went wrong.. but because all the logic for deleting messages is in my model it’s quite hard to do this.

Can anyone provide a solution with an example of how I could use some kind of condition to show my success message if messages were deleted and an error if they weren’t because something went wrong. There must me some kind of markers I can put in the class methods to confirm they have passed a certain point successfully.

Thanks for your time
Kind regards

Answer 1

There are two suggestions I’d make for you here.

The first is have your methods return false if what they were called to do didn’t happen. So, have something like this:

if thread.delete && Message.delete_all(:parent_id => parent_id)
  return true
else
  return false
end

Then in your controller you can check the status of the method:

def destroy_all_messages
  if Message.delete_all_users_messages(current_user.id, params[:format])
    flash[:success] = "Messages deleted"
    redirect_to messages_path
  else
    flash[:error] = "Messages could not be deleted"
    render :action => :show
  end
end

This is the method I would recommend; if you need multiple error messages for different steps in the process, I would break apart your delete_all_user_messages method into separate components, each one indicating true or false for whether they succeeded or failed.

Alternatively, you could raise custom error messages and rescuing them in your code. Something like this:

raise ThreadNotDeleted unless thread.delete 

And then in your controller you rescue ThreadNotDeleted and deal with it there. While this works I think the other method is preferable.