Adding sync of follow relationships to Neo4J, accounts/suggestions API

.gitignore

@@ -21,3 +21,4 @@ public/assets
 .env
 .env.*
 node_modules/
+neo4j/

Gemfile

@@ -39,6 +39,7 @@ gem 'will_paginate'
 gem 'rack-attack'
 gem 'sidekiq'
 gem 'ledermann-rails-settings'
+gem 'neography'
 
 gem 'react-rails'
 gem 'browserify-rails'

Gemfile.lock

@@ -97,6 +97,7 @@ GEM
       dotenv (= 2.1.1)
       railties (>= 4.0, < 5.1)
     erubis (2.7.0)
+    excon (0.53.0)
     execjs (2.7.0)
     fabrication (2.15.2)
     fast_blank (1.0.0)
@@ -165,13 +166,21 @@ GEM
     mime-types-data (3.2016.0521)
     mimemagic (0.3.0)
     mini_portile2 (2.1.0)
-    minitest (5.9.0)
+    minitest (5.9.1)
     multi_json (1.12.1)
+    neography (1.8.0)
+      excon (>= 0.33.0)
+      json (>= 1.7.7)
+      multi_json (>= 1.3.2)
+      os (>= 0.9.6)
+      rake (>= 0.8.7)
+      rubyzip (>= 1.0.0)
     nio4r (1.2.1)
     nokogiri (1.6.8.1)
       mini_portile2 (~> 2.1.0)
     oj (2.17.3)
     orm_adapter (0.5.0)
+    os (0.9.6)
     ostatus2 (1.0.1)
       addressable (~> 2.4)
       http (~> 2.0)
@@ -236,7 +245,7 @@ GEM
       rake (>= 0.8.7)
       thor (>= 0.18.1, < 2.0)
     rainbow (2.1.0)
-    rake (11.2.2)
+    rake (11.3.0)
     rdoc (4.2.2)
       json (~> 1.4)
     react-rails (1.8.2)
@@ -281,6 +290,7 @@ GEM
       ruby-progressbar (~> 1.7)
       unicode-display_width (~> 1.0, >= 1.0.1)
     ruby-progressbar (1.8.1)
+    rubyzip (1.2.0)
     safe_yaml (1.0.4)
     sass (3.4.22)
     sass-rails (5.0.6)
@@ -370,6 +380,7 @@ DEPENDENCIES
   letter_opener
   link_header
   lograge
+  neography
   nokogiri
   oj
   ostatus2

app/assets/javascripts/components/actions/suggestions.jsx

+import api from '../api';
+
+export const SUGGESTIONS_FETCH_REQUEST = 'SUGGESTIONS_FETCH_REQUEST';
+export const SUGGESTIONS_FETCH_SUCCESS = 'SUGGESTIONS_FETCH_SUCCESS';
+export const SUGGESTIONS_FETCH_FAIL    = 'SUGGESTIONS_FETCH_FAIL';
+
+export function fetchSuggestions() {
+  return (dispatch, getState) => {
+    api(getState).get('/api/v1/accounts/suggestions').then(response => {
+      console.log(response.data);
+    }).catch(error => {
+      console.error(error);
+    });
+  };
+};

app/controllers/api/v1/accounts_controller.rb

 class Api::V1::AccountsController < ApiController
   before_action :doorkeeper_authorize!
-  before_action :set_account, except: :verify_credentials
+  before_action :set_account, except: [:verify_credentials, :suggestions]
   respond_to    :json
 
   def show
@@ -19,6 +19,10 @@ class Api::V1::AccountsController < ApiController
     @followers = @account.followers
   end
 
+  def suggestions
+    @accounts = FollowSuggestion.get(current_user.account_id)
+  end
+
   def statuses
     @statuses = @account.statuses.with_includes.with_counters.paginate_by_max_id(20, params[:max_id], params[:since_id]).to_a
   end

app/models/follow.rb

@@ -22,4 +22,28 @@ class Follow < ApplicationRecord
   def title
     destroyed? ? "#{account.acct} is no longer following #{target_account.acct}" : "#{account.acct} started following #{target_account.acct}"
   end
+
+  after_create  :add_to_graph
+  after_destroy :remove_from_graph
+
+  private
+
+  def add_to_graph
+    neo = Neography::Rest.new
+
+    a = neo.create_unique_node('account_index', 'Account', account_id.to_s, account_id: account_id)
+    b = neo.create_unique_node('account_index', 'Account', target_account_id.to_s, account_id: target_account_id)
+
+    neo.create_unique_relationship('follow_index', 'Follow', id.to_s, 'follows', a, b)
+  rescue Neography::NeographyError => e
+    Rails.logger.error e
+  end
+
+  def remove_from_graph
+    neo = Neography::Rest.new
+    rel = neo.get_relationship_index('follow_index', 'Follow', id.to_s)
+    neo.delete_relationship(rel)
+  rescue Neography::NeographyError => e
+    Rails.logger.error e
+  end
 end

app/models/follow_suggestion.rb

+class FollowSuggestion
+  def self.get(for_account_id)
+    neo = Neography::Rest.new
+    account_ids = neo.execute_query('START a=node:account_index(Account={id}) MATCH (a)-[:follows]->(b)-[:follows]->(c) WHERE a <> c AND NOT (a)-[:follows]->(c) RETURN DISTINCT c.account_id', id: for_account_id)
+    Account.where(id: account_ids['data'].first) unless account_ids.empty?
+  end
+end

app/views/api/v1/accounts/suggestions.rabl

+collection @accounts
+extends('api/v1/accounts/show')

config/application.rb

@@ -22,8 +22,8 @@ module Mastodon
     # config.i18n.load_path += Dir[Rails.root.join('my', 'locales', '*.{rb,yml}').to_s]
     # config.i18n.default_locale = :de
 
-    config.paths.add File.join('app', 'api'), glob: File.join('**', '*.rb')
-    config.autoload_paths += Dir[Rails.root.join('app', 'api', '*')]
+    # config.paths.add File.join('app', 'api'), glob: File.join('**', '*.rb')
+    # config.autoload_paths += Dir[Rails.root.join('app', 'api', '*')]
 
     config.active_job.queue_adapter = :sidekiq
 

config/initializers/neography.rb

+Neography.configure do |config|
+  config.protocol             = "http"
+  config.server               = ENV['NEO4J_HOST'] || 'localhost'
+  config.port                 = ENV['NEO4J_PORT'] || 7474
+end

config/routes.rb

@@ -73,6 +73,7 @@ Rails.application.routes.draw do
         collection do
           get :relationships
           get :verify_credentials
+          get :suggestions
         end
 
         member do