Restful Objects - Topological sort app

Example application that uses the Restful Objects for Ruby framework.

Live demo

This project is running live as a free Heroku app at http://topological-sort.herokuapp.com.

Running locally - step by step

• Be sure you have a running ruby environment of at least 1.9.3 or higher:

$ ruby -v
ruby 1.9.3p448 (2013-06-27 revision 41675) [x86_64-linux]

If not install ruby first.

• Bundler is the gem library manager for Ruby, check it is installed:

$ bundle -v
Bundler version 1.3.5

If not, install it by running:

$ gem install bundler

• Clone this repository with git:

$ git clone https://github.com/vizcay/ro_topological_sort.git

• Start the application server

$ cd ro_topological_sort
$ bundle exec restful_server.rb topological_sort.rb
[2014-09-07 01:42:52] INFO  WEBrick 1.3.1
[2014-09-07 01:42:52] INFO  ruby 1.9.3 (2013-06-27) [x86_64-linux]
== Sinatra/1.4.4 has taken the stage on 4567 for development with backup from WEBrick
[2014-09-07 01:42:52] INFO  WEBrick::HTTPServer#start: pid=10116 port=4567

As you can see it's running at http://localhost:4567 you can play with it now.

Topological sort

This example executes the topological sort algorithm at a Graph, for example:

it 'should solve simple dependency problem' do
  graph = Graph.new
  a = graph.add_node('A')
  b = graph.add_node('B')
  c = graph.add_node('C')

  b.dependencies << a
  c.dependencies << b

  expect(graph.topological_sort.map { |n| n.label }).to eq ['A', 'B', 'C']
end

This is the same code executed throught the http api:

it 'should solve simple dependencies' do
  get '/services/GraphFactory/actions/create/invoke'
  graph_url = JSON.parse(last_response.body)['result']['links'].find { |link| link['rel'] == 'self' }['href']

  get graph_url + '/actions/add_node/invoke', {}, { input: { 'label' => {'value' => 'A'} }.to_json }
  n1_url = JSON.parse(last_response.body)['result']['links'].find { |link| link['rel'] == 'self' }['href']

  get graph_url + '/actions/add_node/invoke', {}, { input: { 'label' => {'value' => 'B'} }.to_json }
  n2_url = JSON.parse(last_response.body)['result']['links'].find { |link| link['rel'] == 'self' }['href']

  get graph_url + '/actions/add_node/invoke', {}, { input: { 'label' => {'value' => 'C'} }.to_json }
  n3_url = JSON.parse(last_response.body)['result']['links'].find { |link| link['rel'] == 'self' }['href']

  put n2_url + '/collections/dependencies', {}, { input: { 'value' => { 'href' => n1_url } }.to_json }
  put n3_url + '/collections/dependencies', {}, { input: { 'value' => { 'href' => n2_url } }.to_json }

  get graph_url + '/actions/topological_sort/invoke'
  labels = JSON.parse(last_response.body)['result']['value'].map do |node|
     get node['href']
     JSON.parse(last_response.body)['members']['label']['value']
  end

  expect(labels).to eq ['A', 'B', 'C']
end

Resources

• Restful Objects Spec
• Introduction to Restful Objects

License

MIT License.

Credits

This project has been developed as the main subject of Pablo Vizcay undergradute System's Engineering thesis, directed by Dr. Alejandro Zunino for the U.N.I.C.E.N. University in Tandil - Buenos Aires - Argentina.