sn3fru/Meteor-Leaderboard-Neo4j

Neo4j database powered standard --example Leaderboard Meteor app

This is example for Neo4jreactivity

From this repository you will find out how to use Neo4j and Meteor within Neo4jreactivity atmospherejs.com package

Additional functionality:

• User remove
• User search

Install

Neo4j

Pick up Neo4j version from Official Neo4j Website After download - unzip and place into root folder of your user (name it neo4j), then in Terminal run:

cd ~/neo4j #downloaded and replaced folder
bin/neo4j start

• Note: Neo4j database should be running before Meteor *

Node.js

Pick up version for your system on Official Node.js Website Follow installer instructions

Meteor

Run this in Terminal:

curl https://install.meteor.com/ | sh

Neo4j NPM Package

To install Neo4j NPM Package, run this in Terminal:

npm -g install neo4j

Clone this repository

Run in Terminal:

git clone git@github.com:VeliovGroup/Meteor-Leaderboard-Neo4j.git
cd Meteor-Leaderboard-Neo4j

Running meteor

Run a line below in Terminal, inside Meteor-Leaderboard-Neo4j folder:

meteor

What next

• In your browser go to localhost:3000
• To see Neo4j browser, go to localhost:7474

---

How we rewrite Leaderboard example to be used with Neo4j

In article below you will understand the basics of ostrio:neo4jreactivity and ostrio:neo4driver packages. How to translate queries and other code from MongoDB to Neo4j. How to write basic query in Neo4j. How to use reactivity in Neo4j.

Meteor’s Leaderboard example app, driven by Neo4j database

We've decided to take very basic example application at Meteor - "Leaderboard" and move it from MongoDB to Neo4j.

Prepare dev stage:

Create example app

First of all download Meteor and Neo4j onto your working machine, then run:

$ meteor create --example leaderboard
$ cd leaderboard
$ meteor

Run Neo4j DB

Run inside of Neo4j directory:

$ bin/neo4j start

Installing Neo4j Meteor’s drivers

$ meteor add ostrio:neo4jreactivity

---

Writing the code

Understanding the “Leaderboard” sources

• When server start, it is creates Players
• In template’s helper players - all players ordered by score
• In template’s helper selectedName - player name comes via findOne method
• Incrementation of score implemented via update method

Let’s put our hands on it

Moving to Neo4j:

At first let’s create neo4j config file lib/neo4j.js:

/* Allow client query execution */
Meteor.neo4j.allowClientQuery = true;
/* Custom URL to Neo4j should be here */
/* CHANGE THIS LINE IN ACCORDING TO YOUR NEO4J SETTINGS */
Meteor.neo4j.connectionURL = 'http://user:password@localhost:7474';
/* But deny all writing actions on client */
Meteor.neo4j.set.deny(neo4j.rules.write);

Let’s move to leaderboard.js file and change this line [Isomorphic]:

/* Players = new Mongo.Collection("players"); */
var Players = Meteor.neo4j.collection('players');

This is isomorphic code, so we have all data we need inside Players variable on both - server and client sides.

First, we need to publish some data to client [Client]:

Players.publish('allPlayers', function(){
  return 'MATCH (node:Player) RETURN node ORDER BY node.score DESC';
});

And check if we have users or not, if not - create new users [Server]:

Players.publish('allPlayers', function(){
  return 'MATCH (node:Player) RETURN node ORDER BY node.score DESC';
}, function(){
  if (Players.find({}).count() <= 0) {
    var names = [ 'Ada Lovelace', 
                  'Grace Hopper', 
                  'Marie Curie',
                  'Carl Friedrich Gauss', 
                  'Nikola Tesla', 
                  'Claude Shannon'];
    var players = [];
    _.each(names, function (name) {
      players.push({
        name: name, 
        score: Math.floor(Random.fraction() * 10) * 5,
        __labels: ':Player' /* Assign Cypher label to all nodes */
      });
    });
    Players.insert(players);
});

To generate Players we can use several methods, all methods below is reactive and works almost in same way, the players variable is array of objects {[Object]}:

Players.insert(players);
/* or */
Meteor.neo4j.query('CREATE (a:Player {players})', {players: players});
/* or */
Meteor.N4JDB.query('CREATE (a:Player {players})', {players: players});

To increment ‘score’, we will use standard update method as we use in mongo [Client]:

Players.update({
  _id: Session.get('selectedPlayer')
},{
  '$inc': {
    score: 1
  }
});

To create new user - we only will add the __label property [Client]:

Players.insert({
  name: $('#newPlayerName').val(),
  score: 0,
  __labels: ':Player'
});

To return Players list on client side, we will find all nodes with Player label and sort them [Client]:

Template.leaderboard.helpers({
  players: function () {
    Players.find({'metadata.labels': 'Player'}, {
      sort:{
        score: -1
      }
    });
  },
  ...
});