Loading entries by sparql (mv'd 4store.rb), ordered status via rdf

1 files changed, 122 insertions, 0 deletions

diff --git a/lib/4store.rb b/lib/4store.rb
new file mode 100644
index 0000000..3ed081d
--- /dev/null
+++ b/lib/4store.rb
@@ -0,0 +1,122 @@
+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 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.} 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
+        resource_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
+          bad_request_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
+          RestClientWrapper.put File.join(four_store_uri,"data",uri), rdf, :content_type => mime_type 
+        #rescue
+          #bad_request_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
+            regex = Regexp.new '(https?:\/\/[\S]+)([>"])'
+            turtle =  "<html><body>" + turtle.gsub( regex, '<a href="\1">\1</a>\2' ).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
+        bad_request_error $!.message, sparql_uri
+      end
+
+      def self.klass
+        RDF::OT[SERVICE.capitalize]
+      end
+
+      def self.four_store_uri
+        # credentials are removed from uri in error.rb
+        $four_store[:uri].sub(%r{//},"//#{$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