Mongoid_slug Rails 4 update / destroy object - ruby-on-rails-4

Question

I am using mongoig_slug gem in my rails app.
I can create an object with the proper url but I can't update / delete the object and I have no error message in the console. (I can edit the form, which contains the correct data)
I even used PRY to check in the console and when I check #book exits and is correct, if I do #book.destroy it says true but does not destroy.
For the edit, I also checked #book, I also checked book_params which is correct.
class Book
include Mongoid::Document
include Mongoid::Timestamps
include Mongoid::Slug
field :_id, type: String, slug_id_strategy: lambda {|id| id.start_with?('....')}
field :name, type: String
slug :name
end
class BooksController < ApplicationController
before_filter :get_book, only: [:show, :edit, :update, :destroy]
def update
if #book.update_attributes(book_params)
redirect_to book_path(#book)
else
flash.now[:error] = "The profile was not saved, please try again."
render :edit
end
end
def destroy
binding.pry
#book.destroy
redirect_to :back
end
def book_params
params.require(:book).permit(:name)
end
def get_book
#book = Book.find params[:id]
end
end

Answer 1

You can't just copy that line slug_id_strategy: lambda {|id| id.start_with?('....')} without changes. You should replace dots with something that defines is it id or not.
From docs:
This option should return something that responds to call (a callable) and takes one string argument, e.g. a lambda. This callable must return true if the string looks like one of your ids.
So, it could be, for example:
slug_id_strategy: lambda { |id| id.start_with?('5000') } # ids quite long and start from the same digits for mongo.
or:
slug_id_strategy: lambda { |id| =~ /^[A-z\d]+$/ }
or probably:
slug_id_strategy: -> (id) { id =~ /^[[:alnum:]]+$/ }
Updated
The latest version of mongoid_slug is outdated, you should use github version. So in your Gemfile:
gem 'mongoid_slug', github: 'digitalplaywright/mongoid-slug'
Also change field: _id line to:
field :_id, type: BSON::ObjectId, slug_id_strategy: lambda { |id| id =~ /^[[:alnum:]]+$/ }
Cause _id type is not a string, and this occurs error. This should work.