The gem is not Production Ready™.

Neoon

A simple Ruby wrapper for Neo4j with focus on Cypher and the features of Neo4j 2.0

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Installation

Add this line to your application's Gemfile:

gem 'neoon'

And then execute:

$ bundle

Or install it yourself as:

$ gem install neoon

Usage

You can easily install Neo4j in your application path:

bundle exec rake neo4j:server:install

Then start(stop/restart) the Neo4j server by:

bundle exec rake neo4j:server:start

bundle exec rake neo4j:server:stop

bundle exec rake neo4j:server:restart

First you have to initialize a client:

ENV["NEO4J_URL"] ||= "http://localhost:7474"

$neo = Neoon.client ENV["NEO4J_URL"]

Set configuration:

Neoon.configure do |config|
  config.preload_models = true # This will load your models — helps updating the indexed nodes at the (Rails) boot (default: false)
end

To query using Cypher:

$neo.q('START node=node(*) RETURN node')

With ActiveRecord models, initialize Neoon like so (with example of using properties/index):

class Topic < ActiveRecord::Base

  include Neoon::Node

  neoon do |c|
    c.property :name, :index => true
    c.property :slug, :index => :unique do
      "#{self.id}-#{self.name.underscore}"
    end
    c.property :created_at
  end

end

Indexing

This will be used internally to auto index models nodes.

Topic.neo_index_list #=> { :name => true, :slug => "UNIQUENESS" }

#
# Sync the indexed nodes as described in each model config. It returns the indexed fields.
# Remember, this will be called on each model on the boot if preload_models set to true.
Topic.neo_schema_update #=> { :name => true, :slug => "UNIQUENESS" }

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Neoon::Cypher::Query

Neoon::Cypher::InstanceQuery should be initialized with an Class name or label. You can use Neoon::Cypher::Query to manually create indexes, constraints, etc.

l = Neoon::Cypher::Query.new('Person')

l.create_index(:name)
# l.drop_index(:name)

l.create_constraint(:username)
# l.drop_constraint(:username)

l.list_indexes                         #=> { :name => true, :username => "UNIQUENESS" }

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Neoon::Cypher::InstanceQuery

Neoon::Cypher::InstanceQuery should be initialized with an object that respond to id, class.name as it will represent the label and neo_node_properties as it will represent the args.

You can use Neoon::Cypher::InstanceQuery to manually create operations on nodes related to an object, etc.

Use it with Struct:

Customer = Struct.new(:id, :neo_node_properties)
cus = Customer.new(50, {:name => 'Julie', :address => 'PS'})

c = Neoon::Cypher::InstanceQuery.new(cus)

c.find_node    #=> Return node in Neo4j if already saved
c.create_node  #=> Create object node / or update it
c.delete_node  #=> Remove object node

Note that the key of finding nodes in Neo4j is id as saved in Neo4j with key _id.

Another example on the model we defined above:

t = Neoon::Cypher::InstanceQuery.new(Topic.first)

t.find_node    #=> Returns node in Neo4j if already saved
t.create_node  #=> Create object node / or update it
t.delete_node  #=> Remove object node

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The gem is still at heavy development. More to come!

TODO

1. Add inline docs
2. ADD TESTS!!!

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request