I've been working with Neo4j for something like two years now. I started with Ruby and Neo4j.rb 2.3, which used JRuby 1.7.x with Neo4j Embedded 1.9, and learned Ruby, Neo4j, Rails, and the Neo4j.rb gem concurrently. Funny as it might be, I made it pretty far without ever writing much more than an extremely basic Cypher query for over a year. Phillymetal.com is built entirely on this stack but there's very little "graphy" stuff going on. Neo4j Embedded is so fast that working with the database has almost no overhead for simple find/return/traverse operations, so I was mostly exploiting the easy data modeling and schema-free goodness.

Things changed last year when I started contributing heavily to the Neo4j.rb gem, then got even more intense when I ramped up work on my own project. As performance became more of a concern, I started writing more Cypher to limit the number of queries in and out of the database. As it turns out, Ruby seems to be Neo4j.rb's biggest problem, but the fact is still that the REST API with Neo4j 2.1.7 is just not as performant as Java and Neo4j Embedded.

Enter unmanaged extensions and the Java API. Neo4j has a very cool feature: since it is open source and exposes a REST API, they provide an easy way to write your own plugins, "unmanaged extensions," that expose new REST endpoints. Once your data hits that endpoint, you can use the Java API to do all your work, then you return whatever you want back to your application. This gives you the best of both worlds: Cypher when you need it, Java API for the heavy lifting. Without exception, everyone I know who needs serious performance from Neo4j has told me that they fall back to this method.

At work, we're building an ambitious social media analytics platform that relies heavily on Neo4j. It's collecting a lot of data and revealing a lot of interesting connections. The front-end app is a client of the JSON API my team is building and the goal is for it to have the feel of a desktop app. This means it wants a ton of data very fast. Unfortunately, the combination of our query, the amount of data, the REST API, and Neo4j.rb just do not make for the performance we're looking for. Without getting into how much data we're returning, I can say that we've been seeing 1.5s responses when we really need something closer to 400ms.

I took some steps to improve performance but each time, I got smacked down. I patched Neo4j-core's Query class with an unwrapped method that returns simpler objects, I implemented the amazing GraphAware TimeTree plugin, I optimized the hell out of my query, but we were still having these issues; in fact, the 1.5s response mentioned above is AFTER these optimizations!

After hearing so much about the power of unmanaged extensions, I thought this might be a good opportunity to dive in. Problem was, I had never written a line of Java before. Hell, I had never successfully read a line of Java! Still, I knew what I wanted to do: take the complex Cypher query we're running, rewrite it in Java, return JSON that is usable in the app. To do this, I started looking for resources about Java that were aimed at Rubyists. I figured that with the popularity of both languages, there had to be something out there for Ruby devs looking to learn Java... right? Wrong. Everything I could find was about going from Java to Ruby. Coooool...

I figured I might as well dive into TimeTree to see if I could figure some of it out. I started with the API, since it was all I was really interacting with directly. https://github.com/graphaware/neo4j-timetree/blob/master/src/main/java/com/graphaware/module/timetree/api/TimeTreeApi.java has all the endpoints and figuring out what methods were being called was easy enough. It was also pretty trivial to expose a new endpoint, take a few params, and... make the whole thing crash. A lot.

A few searches and half a book on a plane ride later, I made it to a point that I was able to hack together my own unmanaged extension. In the span of seven days, I was able to write it, extract it from TimeTree, test it, and get it into staging. Our report now runs at around 400ms and I'm going to move more of our app's code into Java ASAP. Victory!

I'm writing this post and what I hope will be a few companion pieces for two reasons.

First, from a Neo4j dev's perspective, I want to illustrate the power of the Java API compared to Cypher. This is not a knock on Cypher in any way, because it is a fantastically expressive, readable, powerful language that I'm always happy to work with, but the superior control you have over your data within Java just can't be understated.

Second, separate from Java, I want to provide a resource for other people who may be in my shoes: Ruby devs who want or need to learn Java quickly but don't want to read through a book that spends a significant amount of time on familiar principles of OOP. As I work with Java, it's going to be harder to remember how I felt about it when I got started, so now is the time to do this.

I don't expect there to be more than one or two other posts about this and I doubt that either of them will be very heavy on Neo4j, if they're mentioned at all. Though I may mention it, it's really not much more than a reference for how I figured some things out. If you are an experienced Java developer, please don't blast me if/when I misstate details, since I'm still learning here.

I'm going to start working on the first piece of this immediately, so stay tuned!

While this blog might not really show it, 2014 was one of the best and worst years of my life.

Professionally, it was a landmark year. In March, I left my job with Valiant Technology, the place that got me out of Philadelphia and into NYC. The end of my time with Valiant also marked the end of my time in that part of the IT industry after nearly 10 years. Goodbye, Hyper-V; hello, Heroku.The plan was to get a startup off the ground. It didn't exactly work out that way, but something even better happened: I realized how much I needed to grow by allowing Neo4j.rb to consume me.

Working with Neo4j and parent Neo Technology resulted in trips to Malmö, Sweden and San Francisco. It opened countless doors, helped me make lot of new friends, and helped me find a sense of both community and professional satisfaction that I've never really known. I wrote a lot of blog posts and made nearly 1500 commits on Github. Phillymetal.com relaunched, I participated in a whirlwind hackathon (that I'll link to when I move it to its new home), and just generally made a ton of stuff I'm extremely proud of. I put my ADHD hyper-focus to use and learned, learned, learned.

There was stress — a shitload of it. If not for the patience and support of my amazing girlfriend, who also left her job for the big ???? of freelance life only to end up in a fantastic new role of her own, I'd have been homeless or living on some generous person's couch sometime around September. I had some lucky breaks along the way (thank you, Utpal and Michael!) and just this morning, I accepted a full-time offer that came largely as a result of my obsessive open source work, dedication to not being shitty at things, and a whole lot of luck. This whole rags-to-something-better-than-rags story will make a better post sometime; for now, the point is that I feel as though it was all worth it because I no longer feel like I'm treading water in an industry that doesn't really have a future for me.

That was the good. It was a banner year, one I'll remember as a massive turning point thanks to the new opportunities and irons on the fire as we enter 2015. But if it was to sit on a scale, if I heaped in every single positive event, big and small, every tiny victory and massive conquest, and condensed it into something tangible, I don't think it could outweigh the single moment of devastation that occurred on January 29, 2014: my mom died of cancer. It crept up on us barely 8 months after it reappeared from 15 years of remission. Melanoma. She went into the hospital with stomach pain one night and was gone the next.

I haven't really written much about it and other than a post on Facebook and some time off of work and I don't think I've even typed it out in months. Seeing it on the screen still kind of feels like a shock. Things changed immediately after it happened: I couldn't handle life in the office, I couldn't deal with other people's schedules or attitudes — hell, I just couldn't deal with other people. A lot of my behavior since then — the decision to switch fields and work by myself from home, the unblinking focus on code, the freezing of every music project, silence on so many public tragedies that normally would have found me engaging in debate — I wonder how much of it was influenced by this. So much of this year was spent trying to process what happened. When the smoke cleared enough for me to see the other side, I think my priorities had changed. I found myself wanting to provide for my father, in whose household my mom was always CEO. I'm so much less interested in drama and dealing with personalities, which made me unwilling to pursue recording bands or playing shows or arguing politics or social issues. I'm filled with regret for things I never said or did. I like to think that I'm more careful with words, more deliberate with actions.

Even now, the world is darker, dirtier. It's as if everything is just slightly out of tune and I feel that dissonance all around me, subtle and unnerving; a constant, creeping vibration, profoundly wrong on a visceral level. For months, I kept waiting for my phone to ring and for someone to say, "Chris, we made a mistake! She's here, she's doing great!" Like a superhero who refuses to stay dead, cause nobody really stays dead, right?

No, the world doesn't work like that, and this is a part of life that every child eventually has to deal with. It's just frustrating that it should happen this year. I feel robbed of the opportunity to show her how things are working out, that her unflinching support and confidence for nearly 30 years wasn't misplaced. It's an incomprehensible feeling, to be so angry an existence itself but not really having anyone or anything specific to blame.

I try to reserve my blog for helpful things, how-tos and records of triumph, or at least cool things I come across as I go, but it didn't seem right to let this year close out without documenting 2014's twisting river of successful and failure. I don't mean to reduce the loss of my mother to some sort of apologue, but if I had to try and explain why I wanted to present this publicly, it would be to make a statement about the interconnectedness of all things. More than ever before, I am aware that we are all products of innumerable people's decisions and actions, nature's amorality, random coincidences, good and bad timing, and a whole lot of generous people. No matter how hard we work at things, we can take a step back and think about what led up to the opportunities, taken and missed, that shape our lives. Hard work is important, but so is awareness of the influence of everyone and everything around us; more importantly, we should take inventory of how cruelly fate could work out, how much worse things could always be.

I think of all the ways it could have been worse, of kids robbed of their parents as children, or kids who never know their parents, or kids who know their parents and hate them or are hated by them. My mom would tell me to think back on this year and be proud of my accomplishments, look after my father, love my friends and girlfriend, and do everything to the best of my abilities. She'd tell me to focus not on loss, but on success, the future, and the things I do have instead of the things I don't. It's a process, I guess, one I've never been very good at, but I'm doing my best, and I guess that's all anyone can really ask for.

class Api::V1::EventsController & ApplicationController
  has_users_route

  # normal methods
end

namespace :api do
  namespace :v1 do
    resources :events do
      resources :users, to: 'user_security'
    end
    resources :bands do
      resources :users, to: 'user_security'
    end
    # repeat about 15 times
  end
end

module UserAuthorization
  extend ActiveSupport::Concern

  module ClassMethods
    def register_new_resource(controller_name)
      MyApp::Application.routes.draw do
        puts "Adding #{controller_name}"
        namespace :api do
          namespace :v1 do
            resources controller_name.to_sym do
              resources :users, controller: 'user_security', param: :given_id
            end
          end
        end
      end
    end
  end
end

['events', 'bands', 'and so on'].each { |resource| ApplicationController.register_new_resource(resource) }

resources controller_name.to_sym, param: :target_id do
  resources :users, controller: 'user_security', param: :given_id
end

class Api::V1::UserSecurityController & ApplicationController
  before_action :authenticate_user!
  before_action :target_id

  private
  attr_reader :root_resource

  def target_id
    @target_id ||= get_target_id
  end

  def get_target_id
    @root_resource = request.fullpath.split('/')[3].singularize
    params["#{root_resource}_id".to_sym]
  end

  def target_model
    @target_model ||= root_resource.capitalize.constantize
  end

  def given_id
    params[:given_id]
  end
end

class User
  include Neo4j::ActiveNode
  has_many :out, :managed_lessons, model_class: Lesson, type: 'manages'

  def create_lesson_rel(lesson)
    if lesson.respond_to?(:managed_by) 
      # create relationship
      # add properties to the relationship
      # call methods on lesson to modify the node
    else
      # failure behavior
    end
  end
end

class User
  include Neo4j::ActiveNode
  property :managed_stats, type: Integer #store the number of managed objects to improve performance

  has_many :out, :managed_lessons,  model_class: Lesson,  rel_class: ManagedRel
  has_many :out, :managed_teachers, model_class: Teacher, rel_class: ManagedRel
  has_many :out, :managed_events,   model_class: Event,   rel_class: ManagedRel
  has_many :out, :managed_objects,  model_class: false,   rel_class: ManagedRel

  def update_stats
    managed_stats += 1
    save
  end
end

class ManagedRel
  include Neo4j::ActiveRel
  after_create :update_user_stats
  before_create :set_performance_review
  validate :manageable_object
  from_class User
  to_class :any
  type 'manages'

  property :created_at
  property :updated_at
  property :next_performance_review, type: DateTime

  def update_user_stats
    from_node.update_stats
  end

  def set_performance_review
    next_performance_review = 6.months.from_now
  end

  def manageable_object
    errors.add(:to_node) unless to_node.respond_to?(:managed_by)
  end
end

# elsewhere
rel = ManagedRel.new(from_node: user, to_node: any_node)
if rel.save
  # validation passed, to_node is a manageable object
else
  # something is wrong
end