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module OpenTox
module Backend
class FourStore
@@accept_formats = [ "application/rdf+xml", "text/turtle", "text/plain", "text/uri-list", "text/html", 'application/sparql-results+xml' ]
@@content_type_formats = [ "application/rdf+xml", "text/turtle", "text/plain" ]
def self.list service_uri, mime_type
mime_type = "text/html" if mime_type.match(%r{\*/\*})
bad_request_error "'#{mime_type}' is not a supported mime type. Please specify one of #{@@accept_formats.join(", ")} in the Accept Header." unless @@accept_formats.include? mime_type
if mime_type =~ /uri-list/
sparql = "SELECT DISTINCT ?g WHERE {GRAPH ?g {?s <#{RDF.type}> <#{klass}>; ?p ?o. } }"
else
sparql = "CONSTRUCT {?s ?p ?o.} FROM WHERE {?s <#{RDF.type}> <#{klass}>; ?p ?o. }"
end
query sparql, mime_type
end
def self.get uri, mime_type
mime_type = "text/html" if mime_type.match(%r{\*/\*})
bad_request_error "'#{mime_type}' is not a supported mime type. Please specify one of #{@@accept_formats.join(", ")} in the Accept Header." unless @@accept_formats.include? mime_type
sparql = "CONSTRUCT {?s ?p ?o.} FROM <#{uri}> WHERE { ?s ?p ?o. }"
rdf = query sparql, mime_type
not_found_error "#{uri} not found." if rdf.empty?
rdf
end
def self.post uri, rdf, mime_type
bad_request_error "'#{mime_type}' is not a supported content type. Please use one of #{@@content_type_formats.join(", ")}." unless @@content_type_formats.include? mime_type or mime_type == "multipart/form-data"
bad_request_error "Reqest body empty." unless rdf
mime_type = "application/x-turtle" if mime_type == "text/plain" # ntriples is turtle in 4store
begin
RestClient.post File.join(four_store_uri,"data")+"/", :data => rdf, :graph => uri, "mime-type" => mime_type
rescue
rest_call_error $!.message, File.join(four_store_uri,"data")+"/"
end
end
def self.put uri, rdf, mime_type
bad_request_error "'#{mime_type}' is not a supported content type. Please use one of #{@@content_type_formats.join(", ")}." unless @@content_type_formats.include? mime_type
bad_request_error "Reqest body empty." unless rdf
mime_type = "application/x-turtle" if mime_type == "text/plain"
begin
RestClient.put File.join(four_store_uri,"data",uri), rdf, :content_type => mime_type
rescue
rest_call_error $!.message, File.join(four_store_uri,"data",uri)
end
end
def self.delete uri
RestClientWrapper.delete data_uri(uri)
end
def self.update sparql
RestClient.post(update_uri, :update => sparql )
end
def self.query sparql, mime_type
if sparql =~ /SELECT/i
# return list unless mime_type
case mime_type
when 'application/sparql-results+xml'
RestClient.get(sparql_uri, :params => { :query => sparql }, :accept => mime_type).body
when "text/uri-list"
RestClient.get(sparql_uri, :params => { :query => sparql }, :accept => "text/plain").body.gsub(/"|<|>/,'').split("\n").drop(1).join("\n")
else
bad_request_error "#{mime_type} is not a supported mime type for SELECT statements."
end
elsif sparql =~ /CONSTRUCT/i
case mime_type
when "text/plain", "application/rdf+xml"
RestClient.get(sparql_uri, :params => { :query => sparql }, :accept => mime_type).body
when /html|turtle/
# TODO: fix and improve
nt = RestClient.get(sparql_uri, :params => { :query => sparql }, :accept => "text/plain").body # 4store returns ntriples for turtle
rdf = RDF::Graph.new
RDF::Reader.for(:ntriples).new(nt) do |reader|
reader.each_statement { |statement| rdf << statement }
end
prefixes = {:rdf => "http://www.w3.org/1999/02/22-rdf-syntax-ns#type"}
['OT', 'DC', 'XSD', 'OLO'].each{|p| prefixes[p.downcase.to_sym] = eval("RDF::#{p}.to_s") }
# TODO: fails for large datasets?? multi_cell_call
turtle = RDF::N3::Writer.for(:turtle).buffer(:prefixes => prefixes) do |writer|
rdf.each{|statement| writer << statement}
end
turtle = "<html><body>" + turtle.gsub(%r{<(.*)>},'<<a href="\1">\1</a>>').gsub(/\n/,'<br/>') + "</body></html>" if mime_type =~ /html/ and !turtle.empty?
turtle
end
else
# TODO: check if this prevents SPARQL injections
bad_request_error "Only SELECT and CONSTRUCT are accepted SPARQL statements."
end
rescue
rest_call_error $!.message, sparql_uri
end
def self.klass
RDF::OT[SERVICE.capitalize]
end
=begin
def self.available? uri
sparql = "SELECT DISTINCT ?s WHERE {GRAPH <#{uri}> {?s <#{RDF.type}> <#{klass}>} }"
r = query(sparql, nil)
r.size == 1 and r.first == uri
end
def self.convert rdf_string, input_format, output_format, rewrite_uri=nil
rewrite_uri ? serialize(parse_and_rewrite_uri(rdf_string,input_format, rewrite_uri), output_format) : serialize(parse(rdf_string,input_format), output_format)
end
def self.parse_and_rewrite_uri string, format, rewrite_uri
rdf = RDF::Graph.new
subject = nil
statements = [] # use array instead of graph for performance reasons
RDF::Reader.for(format).new(string) do |reader|
reader.each_statement do |statement|
subject = statement.subject if statement.predicate == RDF.type and statement.object == klass
statements << statement
end
end
bad_request_error "No class specified with <#{RDF.type}> statement." unless subject
statements.each do |statement|
if rewrite_uri
statement.subject = RDF::URI.new rewrite_uri if statement.subject.to_s == subject
statement.object = RDF::URI.new rewrite_uri if statement.predicate == RDF::XSD.anyURI
end
rdf << statement
end
rdf
end
=end
def self.four_store_uri
# TODO remove credentials from URI 9security risk in tasks)
$four_store[:uri].sub(%r{//},"//#{$four_store[:user]}:#{$four_store[:password]}@")
end
def self.sparql_uri
File.join(four_store_uri, "sparql") + '/'
end
def self.update_uri
File.join(four_store_uri, "update") + '/'
end
def self.data_uri uri
File.join(four_store_uri, "data","?graph=#{uri}")
end
end
end
end
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