Mercurial > repos > greg > greg_sparql

comparison sparql-7785ad38967f/sparql/executor.rb @ 0:46996d3b1cfb default tip

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author greg
date Tue, 13 Mar 2012 16:29:09 -0400
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1 #!/usr/bin/env ruby
2 $: << File.expand_path('../rubylib/lib', File.dirname(__FILE__))
3 $: << File.expand_path('sparql/lib', File.dirname(__FILE__))
4 require "galaxy_tool"
5 require 'rubygems'
6 require 'sparql'
7 require 'rubyrdf'
8
9 class SPARQLExecutor < GalaxyTool::Base
10
11 option :endpoint,
12 :short => "-e",
13 :long => "--endpoint <URL>",
14 :class => String,
15 :description => "use <URL> as SPARQL endpoint.",
16 :proc => proc {|arg| arg.strip },
17 :required => true
18
19 option :query,
20 :long => "--query-file <filepath>",
21 :class => String,
22 :description => "read query expression from <filepath>.",
23 :proc => proc {|arg| File.read(arg).chomp },
24 :required => true
25
26 option :query,
27 :short => "-q",
28 :long => "--query <expression>",
29 :class => String,
30 :description => "use <expression> as query expression.",
31 :proc => proc {|arg| arg.chomp },
32 :required => true
33
34 option_output :short => "-o",
35 :long => "--output <filepath>",
36 :description => "use <filepath> as output file path."
37
38 option_info :long => "--info <filepath>",
39 :description => "use <filepath> as info file path. default is standard out (/dev/stdout)."
40
41 option_error_handler do |optparse, exception|
42 $stderr.puts "Error: " + exception.message
43 $stderr.puts optparse.help
44 raise exception
45 end
46
47 def info(info_out)
48 info_out.puts "Execute SPARQL query. The endpoint is #{options[:endpoint]}.\n"
49 end
50
51 def create_customized_client(endpoint)
52 client = SPARQL::Client.new(endpoint)
53
54 def client.parsed_xml(content)
55 REXML::Document.new(content).root
56 end
57
58 def client.parse_xml(content)
59 table = []
60 xml = parsed_xml(content)
61
62 head = xml.elements['head']
63 variables = head.elements.map do |variable|
64 variable.attributes['name']
65 end
66 table << variables.map {|v| "?" + v }
67
68 case
69 when boolean = xml.elements['boolean']
70 boolean.text == 'true'
71 when results = xml.elements['results']
72 table += results.elements.map do |result|
73 row = []
74 result.elements.each do |binding|
75 name = binding.attributes['name']
76 value_node = binding.children.find {|n| !n.is_a?(REXML::Text) }
77 value = parse_xml_value(value_node)
78 row[variables.index(name)] = value
79 end
80 row
81 end
82 else
83 raise NotImplementedError # TODO
84 end
85
86 table
87 end
88
89 def client.graph
90 @graph ||= RDF::Graph::Memory.new
91 end
92
93 def client.parse_xml_value(element)
94 case element
95 when REXML::Text
96 element.value
97 when REXML::Node
98 case element.name.to_sym
99 when :uri
100 RDF::UriNode.new(element.text)
101 when :literal
102 RDF::PlainLiteralNode.new(element.text)
103 when :bnode
104 RDF::BlankNode.new(element.text, graph)
105 else
106 raise NotImplementedError # TODO
107 end
108 else
109 raise NotImplementedError # TODO
110 end
111 end
112
113 client
114 end
115
116 def search(client, query)
117 client.query(query)
118 end
119
120 def main(output)
121 client = create_customized_client(options[:endpoint])
122 search(client, options[:query]).each do |row|
123 output.puts row.join("\t")
124 end
125 end
126 end
127
128 if $0 == __FILE__
129 SPARQLExecutor.new.run(ARGV)
130 end