https://github.com/afiore/gexf.rb

Ruby library for parsing, serializing, and manipulating GEXF graphs
https://github.com/afiore/gexf.rb

Last synced: 3 months ago
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Ruby library for parsing, serializing, and manipulating GEXF graphs

• Host: GitHub
• URL: https://github.com/afiore/gexf.rb
• Owner: afiore
• Created: 2012-07-14T17:48:31.000Z (over 12 years ago)
• Default Branch: master
• Last Pushed: 2014-01-31T11:57:06.000Z (almost 11 years ago)
• Last Synced: 2024-07-28T10:03:16.617Z (4 months ago)
• Language: Ruby
• Homepage:
• Size: 166 KB
• Stars: 21
• Watchers: 1
• Forks: 13
• Open Issues: 3
• Metadata Files:
  • Readme: README.md

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README

        
# Gexf.rb

A Ruby library for generating, parsing, and serializing graphs expressed in the [GEXF](http://gexf.net) format.

Currently, this project implements only a subset of the GEXF specification: the definition of a basic graph topology,

and the association of data attributes to nodes and edges. I will possibly implement the rest of the specification later on

(i.e. dynamics, hyrarchy, and Phylogeny), as I consolidate the code.

## Notice

This gem is not under active development anymore. However, you are wellcome to

contribute pull requests, I will do my best to find the time for reviewing and possibly merging them.

## Installation

    gem install gexf

## Usage

The following snippet initializes a GEXF graph, and defines three node attributes:

````ruby

require 'rubygems'

require 'gexf'

graph = GEXF::Graph.new

graph.define_node_attribute(:url)

graph.define_node_attribute(:indegree, :type    => GEXF::Attribute::INTEGER)

graph.define_node_attribute(:frog,     :type    => GEXF::Attribute::BOOLEAN,

                                       :default => true)

````

Attribute values can be associated to nodes or edges by using the same syntax used

to get/set Ruby Hash keys (symbols are automatically converted into strings).

````ruby

gephi               = graph.create_node(:label => 'Gephi')

gephi[:url]         = 'http://gephi.org'

gephi[:indegree]    = 1

webatlas            = graph.create_node(:label => 'WebAtlas')

webatlas[:url]      = 'http://webatlas.fr'

webatlas[:indegree] = 2

rtgi                = graph.create_node(:label => 'RTGI')

rtgi[:url]          = 'http://rtgi.fr'

rtgi[:indegree]     = 1

blab                = graph.create_node(:label => 'BarabasiLab')

blab[:url]          = "http://barabasilab.com"

blab[:indegree]     = 1

blab[:frog]         = false

````

Once associated to a graph, nodes and edges behave as collections,

implementing and exposing most of the methods in Ruby's _Enumerable_ module:

````ruby

graph.nodes.select { |node| !node[:frog] }.map(&:label)

=> 'BarabasiLab'

````

Edges can be created by calling the `graph.create_edges`, or more coincisely, by calling

connect on the source node.

````ruby

gephi.connect_to(webatlas)

gephi.connect_to(rtgi)

webatlas.connect_to(gephi)

rtgi.connect_to(webatlas)

gephi.connect_to(blab)

````

As it is the case for `graph.nodes`, also edges are enumerable:

````ruby

graph.edges.count

=> 5

````

The complete set of edges can be accessed from the main graph object, or fetched

on a single node basis:

````ruby

webatlas.incoming_connections.map { |edge| edge.source.label }

=> ["Gephi", "RTGI"]

````

### Parsing a GEXF document

Gexf.rb provides a basic SAX parser which allows to import GEXF documents into a

graph objects suitable to be queried and manipulated. To parse a GEXF file into a graph, just

call the GEXF helper method (which is a shortcat to `GEXF::Document.parse(file)`)

````ruby

require 'gexf'

require 'open-uri'

file  = File.open('http://gexf.net/data/data.gexf', 'r')

graph = GEXF(file)

file.close

graph.nodes.count

=> 4

````

### Exporting a graph into an XML document

A graph object can be easily serialized to XML by just calling:

````ruby

graph.to_xml

=> "\n"

````

Alternatively, one can obtain the same output by instantiating GEXF::XmlSerializer and calling the `serialize!` method.

````ruby

serializer = GEXF::XmlSerializer.new(graph)

serializer.serialize!

````

## Unit tests

Gexf.rb comes with a fairly decent RSpec test suite. The suite can

be run from the project directory by issuing the following command:

    bundle exec spec -f d spec

### Contributors

- Andrea Fiore

- Erik Doernenburg

- Thiago Bueno