Use Ruby closure_tree gem without rails - ruby-on-rails

Question

I want to try the gem closure_tree to build a tree for my genealogy database.
I installed the gem under Ruby MRI 2.3.0 on a windows 7 box.
The versions of the dependencies are in the errorlog below.
$ gem install closure_tree
Fetching: with_advisory_lock-3.0.0.gem (100%)
Successfully installed with_advisory_lock-3.0.0
Fetching: closure_tree-6.2.0.gem (100%)
Successfully installed closure_tree-6.2.0
2 gems installed
When I try the most minimalistic code it fails, I suppose because I don't use Rails and don't do the migration which again I presume creates the table tag_hierachies
My question is: Can I use this gem without Rails and if so how ?
require 'active_record'
require 'closure_tree'
ActiveRecord::Base.establish_connection(
:adapter => "sqlite3",
:database => "sample.db"
)
if !ActiveRecord::Base.connection.table_exists?('tags')
ActiveRecord::Schema.define do
create_table :tags do |table|
table.column :name, :string
table.column :parent_id, :integer
end
end
end
class Tag < ActiveRecord::Base
has_closure_tree
end
grandparent = Tag.create(name: 'Grandparent')
gives
d:/Ruby/lib/ruby/gems/2.3.0/gems/activerecord-4.2.6/lib/active_record/connection_adapters/sqlite3_adapter.rb:513:in `table_structure': Could not find table 'tag_hierarchies' (ActiveRecord::StatementInvalid)
from d:/Ruby/lib/ruby/gems/2.3.0/gems/activerecord-4.2.6/lib/active_record/connection_adapters/sqlite3_adapter.rb:387:in `columns'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/activerecord-4.2.6/lib/active_record/connection_adapters/schema_cache.rb:43:in `columns'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/activerecord-4.2.6/lib/active_record/attributes.rb:93:in `columns'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/activerecord-4.2.6/lib/active_record/attributes.rb:98:in `columns_hash'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/activerecord-4.2.6/lib/active_record/inheritance.rb:205:in `subclass_from_attributes?'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/activerecord-4.2.6/lib/active_record/inheritance.rb:54:in `new'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/activerecord-4.2.6/lib/active_record/persistence.rb:50:in `create!'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/closure_tree-6.2.0/lib/closure_tree/hierarchy_maintenance.rb:65:in `block in rebuild!'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/closure_tree-6.2.0/lib/closure_tree/support.rb:108:in `block (2 levels) in with_advisory_lock'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/activerecord-4.2.6/lib/active_record/connection_adapters/abstract/database_statements.rb:211:in `transaction'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/activerecord-4.2.6/lib/active_record/transactions.rb:220:in `transaction'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/closure_tree-6.2.0/lib/closure_tree/support.rb:108:in `block in with_advisory_lock'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/with_advisory_lock-3.0.0/lib/with_advisory_lock/base.rb:77:in `yield_with_lock'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/with_advisory_lock-3.0.0/lib/with_advisory_lock/base.rb:65:in `yield_with_lock_and_timeout'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/with_advisory_lock-3.0.0/lib/with_advisory_lock/base.rb:48:in `with_advisory_lock_if_needed'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/with_advisory_lock-3.0.0/lib/with_advisory_lock/concern.rb:16:in `with_advisory_lock_result'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/with_advisory_lock-3.0.0/lib/with_advisory_lock/concern.rb:10:in `with_advisory_lock'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/closure_tree-6.2.0/lib/closure_tree/support.rb:107:in `with_advisory_lock'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/closure_tree-6.2.0/lib/closure_tree/hierarchy_maintenance.rb:63:in `rebuild!'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/closure_tree-6.2.0/lib/closure_tree/hierarchy_maintenance.rb:39:in `_ct_after_save'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/activesupport-4.2.6/lib/active_support/callbacks.rb:432:in `block in make_lambda'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/activesupport-4.2.6/lib/active_support/callbacks.rb:228:in `block in halting_and_conditional'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/activesupport-4.2.6/lib/active_support/callbacks.rb:506:in `block in call'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/activesupport-4.2.6/lib/active_support/callbacks.rb:506:in `each'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/activesupport-4.2.6/lib/active_support/callbacks.rb:506:in `call'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/activesupport-4.2.6/lib/active_support/callbacks.rb:92:in `__run_callbacks__'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/activesupport-4.2.6/lib/active_support/callbacks.rb:778:in `_run_save_callbacks'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/activerecord-4.2.6/lib/active_record/callbacks.rb:302:in `create_or_update'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/activerecord-4.2.6/lib/active_record/persistence.rb:120:in `save'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/activerecord-4.2.6/lib/active_record/validations.rb:37:in `save'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/activerecord-4.2.6/lib/active_record/attribute_methods/dirty.rb:21:in `save'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/activerecord-4.2.6/lib/active_record/transactions.rb:286:in `block (2 levels) in save'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/activerecord-4.2.6/lib/active_record/transactions.rb:351:in `block in with_transaction_returning_status'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/activerecord-4.2.6/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in `block in transaction'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/activerecord-4.2.6/lib/active_record/connection_adapters/abstract/transaction.rb:184:in `within_new_transaction'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/activerecord-4.2.6/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in `transaction'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/activerecord-4.2.6/lib/active_record/transactions.rb:220:in `transaction'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/activerecord-4.2.6/lib/active_record/transactions.rb:348:in `with_transaction_returning_status'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/activerecord-4.2.6/lib/active_record/transactions.rb:286:in `block in save'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/activerecord-4.2.6/lib/active_record/transactions.rb:301:in `rollback_active_record_state!'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/activerecord-4.2.6/lib/active_record/transactions.rb:285:in `save'
from d:/Ruby/lib/ruby/gems/2.3.0/gems/activerecord-4.2.6/lib/active_record/persistence.rb:34:in `create'
from C:/Users/Gebruiker/BoxSync/ruby_werk/acts_as_tree/closure_tree.rb:22:in `<main>'

Answer 1

Seems the installation instructions in README is focused with only Rails in mind. It does however tell you that you need another table(in addition to your current tags table) with the name tag_hierarchies.
In Rails, generation of this table seems to be part of the installation steps; Step 5 in the linked documentation.
So, you should be creating tag_hierarchies table with the following content, which is what rails g closure_tree:migration tag generates as far as the table structure is concerned. See create_hierarchies_table.rb.erb, as you may also want to add index as shown in this linked file.
So, updating your script to following worked as expected for me:
require 'active_record'
require 'closure_tree'
ActiveRecord::Base.establish_connection(
:adapter => "sqlite3",
:database => "sample.db"
)
if !ActiveRecord::Base.connection.data_source_exists?('tags')
ActiveRecord::Schema.define do
create_table :tags do |table|
table.column :name, :string
table.column :parent_id, :integer
end
end
end
# You also need a corresponding model's table name followed by "_hierarchies" table.
#
# Migration created based on
# `https://github.com/mceachen/closure_tree/blob/master/lib/generators/closure_tree/templates/create_hierarchies_table.rb.erb`
if !ActiveRecord::Base.connection.data_source_exists?(:tag_hierarchies)
ActiveRecord::Schema.define do
create_table :tag_hierarchies do |table|
table.integer :ancestor_id, null: false
table.integer :descendant_id, null: false
table.integer :generations, null: false
end
end
end
class Tag < ActiveRecord::Base
has_closure_tree
end
grandparent = Tag.create(name: 'Grandparent')
grandparent.children.create(name: 'Father')
grandparent.children.create(name: 'Uncle')