Class: RDF::Reader Abstract
- Inherits:
-
Object
- Object
- RDF::Reader
- Extended by:
- Enumerable, Util::Aliasing::LateBound
- Includes:
- Enumerable, Readable, Util::Logger
- Defined in:
- lib/rdf/reader.rb
Overview
The base class for RDF parsers.
Direct Known Subclasses
Constant Summary
Constants included from Util::Logger
Instance Attribute Summary collapse
-
#options ⇒ Hash
readonly
Any additional options for this reader.
Class Method Summary collapse
-
.each {|klass| ... } ⇒ Enumerator
Enumerates known RDF reader classes.
-
.for(*arg, &block) ⇒ Class
Finds an RDF reader class based on the given criteria.
-
.format(klass = nil) ⇒ Class
(also: format_class)
Retrieves the RDF serialization format class for this reader class.
-
.open(filename, format: nil, **options) {|reader| ... } ⇒ Object
Parses input from the given file name or URL.
-
.options ⇒ Array<RDF::CLI::Option>
Options suitable for automatic Reader provisioning.
-
.to_sym ⇒ Symbol
Returns a symbol appropriate to use with RDF::Reader.for().
Instance Method Summary collapse
-
#base_uri ⇒ RDF::URI
Returns the base URI determined by this reader.
-
#canonicalize? ⇒ Boolean
Returns
true
if parsed values should be in canonical form. -
#close
(also: #close!)
Closes the input stream, after which an
IOError
will be raised for further read attempts. -
#each_pg_statement(statement, &block) ⇒ Object
protected
Recursively emit embedded statements in Property Graph mode.
-
#each_statement(&block)
(also: #each)
Iterates the given block for each RDF statement.
-
#each_triple(&block)
Iterates the given block for each RDF triple.
-
#encoding ⇒ Encoding
Returns the encoding of the input stream.
-
#fail_object
protected
Raises an “expected object” parsing error on the current line.
-
#fail_predicate
protected
Raises an “expected predicate” parsing error on the current line.
-
#fail_subject
protected
Raises an “expected subject” parsing error on the current line.
-
#initialize(input = $stdin, base_uri: nil, canonicalize: false, encoding: Encoding::UTF_8, intern: true, prefixes: Hash.new, rdfstar: false, validate: false, **options) {|reader| ... } ⇒ Reader
constructor
Initializes the reader.
-
#intern? ⇒ Boolean
Returns
true
if parsed URIs should be interned. -
#lineno ⇒ Integer
Current line number being processed.
-
#prefix(name, uri = nil) ⇒ RDF::URI
(also: #prefix!)
Defines the given named URI prefix for this reader.
-
#prefixes ⇒ Hash{Symbol => RDF::URI}
Returns the URI prefixes currently defined for this reader.
-
#prefixes=(prefixes) ⇒ Hash{Symbol => RDF::URI}
Defines the given URI prefixes for this reader.
-
#read_statement ⇒ RDF::Statement
protected
abstract
Reads a statement from the input stream.
-
#read_triple ⇒ Array(RDF::Term)
protected
abstract
Reads a triple from the input stream.
-
#rewind
(also: #rewind!)
Rewinds the input stream to the beginning of input.
-
#to_sym ⇒ Symbol
Returns a symbol appropriate to use with RDF::Reader.for().
- #valid? ⇒ Boolean
-
#validate? ⇒ Boolean
Returns
true
if parsed statements and values should be validated.
Methods included from Util::Aliasing::LateBound
Methods included from Enumerable
#canonicalize, #canonicalize!, #dump, #each_graph, #each_object, #each_predicate, #each_quad, #each_subject, #each_term, #enum_graph, #enum_object, #enum_predicate, #enum_quad, #enum_statement, #enum_subject, #enum_term, #enum_triple, #graph?, #graph_names, #invalid?, #method_missing, #object?, #objects, #predicate?, #predicates, #project_graph, #quad?, #quads, #respond_to_missing?, #statement?, #statements, #subject?, #subjects, #supports?, #term?, #terms, #to_a, #to_h, #to_set, #triple?, #triples, #validate!
Methods included from Countable
Methods included from Readable
Methods included from Util::Logger
#log_debug, #log_depth, #log_error, #log_fatal, #log_info, #log_recover, #log_recovering?, #log_statistics, #log_warn, #logger
Constructor Details
#initialize(input = $stdin, base_uri: nil, canonicalize: false, encoding: Encoding::UTF_8, intern: true, prefixes: Hash.new, rdfstar: false, validate: false, **options) {|reader| ... } ⇒ Reader
Initializes the reader.
290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 |
# File 'lib/rdf/reader.rb', line 290 def initialize(input = $stdin, base_uri: nil, canonicalize: false, encoding: Encoding::UTF_8, intern: true, prefixes: Hash.new, rdfstar: false, validate: false, **, &block) base_uri ||= input.base_uri if input.respond_to?(:base_uri) @options = .merge({ base_uri: base_uri, canonicalize: canonicalize, encoding: encoding, intern: intern, prefixes: prefixes, rdfstar: rdfstar, validate: validate }) @input = case input when String then StringIO.new(input) else input end if block_given? case block.arity when 0 then instance_eval(&block) else block.call(self) end end end |
Dynamic Method Handling
This class handles dynamic methods through the method_missing method in the class RDF::Enumerable
Instance Attribute Details
#options ⇒ Hash (readonly)
Any additional options for this reader.
330 331 332 |
# File 'lib/rdf/reader.rb', line 330 def @options end |
Class Method Details
.each {|klass| ... } ⇒ Enumerator
Enumerates known RDF reader classes.
53 54 55 |
# File 'lib/rdf/reader.rb', line 53 def self.each(&block) RDF::Format.map(&:reader).reject(&:nil?).each(&block) end |
.for(format) ⇒ Class .for(filename) ⇒ Class .for(options = {}) ⇒ Class
Finds an RDF reader class based on the given criteria.
If the reader class has a defined format, use that.
91 92 93 94 95 96 97 98 99 100 101 102 |
# File 'lib/rdf/reader.rb', line 91 def self.for(*arg, &block) case arg.length when 0 then arg = nil when 1 then arg = arg.first else raise ArgumentError, "Format.for accepts zero or one argument, got #{arg.length}." end arg = arg.merge(has_reader: true) if arg.is_a?(Hash) if format = self.format || Format.for(arg, &block) format.reader end end |
.format(klass = nil) ⇒ Class Also known as: format_class
Retrieves the RDF serialization format class for this reader class.
108 109 110 111 112 113 114 115 116 117 |
# File 'lib/rdf/reader.rb', line 108 def self.format(klass = nil) if klass.nil? Format.each do |format| if format.reader == self return format end end nil # not found end end |
.open(filename, format: nil, **options) {|reader| ... } ⇒ Object
A reader returned via this method may not be readable depending on the processing model of the specific reader, as the file is only open during the scope of open
. The reader is intended to be accessed through a block.
Parses input from the given file name or URL.
209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 |
# File 'lib/rdf/reader.rb', line 209 def self.open(filename, format: nil, **, &block) # If we're the abstract reader, and we can figure out a concrete reader from format, use that. if self == RDF::Reader && format && reader = self.for(format) return reader.open(filename, format: format, **, &block) end # If we are a concrete reader class or format is not nil, set accept header from our content_types. unless self == RDF::Reader headers = ([:headers] ||= {}) headers['Accept'] ||= (self.format.accept_type + %w(*/*;q=0.1)).join(", ") end Util::File.open_file(filename, **) do |file| = .dup [:content_type] ||= file.content_type if file.respond_to?(:content_type) && !file.content_type.to_s.include?('text/plain') [:file_name] ||= filename reader = if self == RDF::Reader # We are the abstract reader class, find an appropriate reader self.for(format || ) do # Return a sample from the input file sample = file.read(1000) file.rewind sample end else # We are a concrete reader class self end [:encoding] ||= file.encoding if file.respond_to?(:encoding) [:filename] ||= filename if reader reader.new(file, **, &block) else raise FormatError, "unknown RDF format: #{.inspect}#{"\nThis may be resolved with a require of the 'linkeddata' gem." unless Object.const_defined?(:LinkedData)}" end end end |
.options ⇒ Array<RDF::CLI::Option>
Options suitable for automatic Reader provisioning.
122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 |
# File 'lib/rdf/reader.rb', line 122 def self. [ RDF::CLI::Option.new( symbol: :base_uri, control: :url, datatype: RDF::URI, on: ["--uri URI"], description: "Base URI of input file, defaults to the filename.") {|arg| RDF::URI(arg)}, RDF::CLI::Option.new( symbol: :canonicalize, datatype: TrueClass, on: ["--canonicalize"], control: :checkbox, default: false, description: "Canonicalize URI/literal forms") {true}, RDF::CLI::Option.new( symbol: :encoding, datatype: Encoding, control: :text, on: ["--encoding ENCODING"], description: "The encoding of the input stream.") {|arg| Encoding.find arg}, RDF::CLI::Option.new( symbol: :intern, datatype: TrueClass, control: :none, on: ["--intern"], description: "Intern all parsed URIs."), RDF::CLI::Option.new( symbol: :prefixes, datatype: Hash, control: :none, multiple: true, on: ["--prefixes PREFIX:URI,PREFIX:URI"], description: "A comma-separated list of prefix:uri pairs.") do |arg| arg.split(',').inject({}) do |memo, pfxuri| pfx,uri = pfxuri.split(':', 2) memo.merge(pfx.to_sym => RDF::URI(uri)) end end, RDF::CLI::Option.new( symbol: :rdfstar, datatype: TrueClass, control: :checkbox, on: ["--rdfstar"], description: "Parse RDF-star for preliminary RDF 1.2 support."), RDF::CLI::Option.new( symbol: :validate, datatype: TrueClass, control: :checkbox, on: ["--validate"], description: "Validate input file."), RDF::CLI::Option.new( symbol: :verifySSL, datatype: TrueClass, default: true, control: :checkbox, on: ["--[no-]verifySSL"], description: "Verify SSL results on HTTP GET") ] end |
.to_sym ⇒ Symbol
Returns a symbol appropriate to use with RDF::Reader.for()
254 255 256 |
# File 'lib/rdf/reader.rb', line 254 def self.to_sym self.format.to_sym end |
Instance Method Details
#base_uri ⇒ RDF::URI
Returns the base URI determined by this reader.
340 341 342 |
# File 'lib/rdf/reader.rb', line 340 def base_uri RDF::URI(@options[:base_uri]) if @options[:base_uri] end |
#canonicalize? ⇒ Boolean
This is for term canonicalization, for graph/dataset canonicalization use RDF::Normalize
.
Returns true
if parsed values should be in canonical form.
617 618 619 |
# File 'lib/rdf/reader.rb', line 617 def canonicalize? @options[:canonicalize] end |
#close Also known as: close!
This method returns an undefined value.
Closes the input stream, after which an IOError
will be raised for further read attempts.
If the input stream is already closed, does nothing.
486 487 488 |
# File 'lib/rdf/reader.rb', line 486 def close @input.close unless @input.closed? end |
#each_pg_statement(statement, &block) ⇒ Object (protected)
Recursively emit embedded statements in Property Graph mode
573 574 575 576 577 578 579 580 581 582 583 |
# File 'lib/rdf/reader.rb', line 573 def each_pg_statement(statement, &block) if statement.subject.is_a?(Statement) block.call(statement.subject) each_pg_statement(statement.subject, &block) end if statement.object.is_a?(Statement) block.call(statement.object) each_pg_statement(statement.object, &block) end end |
#each_statement {|statement| ... } #each_statement ⇒ Enumerator Also known as: each
This method returns an undefined value.
Iterates the given block for each RDF statement.
If no block was given, returns an enumerator.
Statements are yielded in the order that they are read from the input stream.
415 416 417 418 419 420 421 422 423 424 425 426 427 |
# File 'lib/rdf/reader.rb', line 415 def each_statement(&block) if block_given? begin loop do st = read_statement block.call(st) end rescue EOFError rewind rescue nil end end enum_for(:each_statement) end |
#each_triple {|subject, predicate, object| ... } #each_triple ⇒ Enumerator
This method returns an undefined value.
Iterates the given block for each RDF triple.
If no block was given, returns an enumerator.
Triples are yielded in the order that they are read from the input stream.
452 453 454 455 456 457 458 459 460 461 462 463 464 |
# File 'lib/rdf/reader.rb', line 452 def each_triple(&block) if block_given? begin loop do triple = read_triple block.call(*triple) end rescue EOFError rewind rescue nil end end enum_for(:each_triple) end |
#encoding ⇒ Encoding
Returns the encoding of the input stream.
590 591 592 593 594 595 596 597 598 599 |
# File 'lib/rdf/reader.rb', line 590 def encoding case @options[:encoding] when String, Symbol Encoding.find(@options[:encoding].to_s) when Encoding @options[:encoding] else @options[:encoding] ||= Encoding.find(self.class.format.content_encoding.to_s) end end |
#fail_object (protected)
This method returns an undefined value.
Raises an “expected object” parsing error on the current line.
565 566 567 |
# File 'lib/rdf/reader.rb', line 565 def fail_object log_error("Expected object (found: #{current_line.inspect})", lineno: lineno, exception: RDF::ReaderError) end |
#fail_predicate (protected)
This method returns an undefined value.
Raises an “expected predicate” parsing error on the current line.
556 557 558 |
# File 'lib/rdf/reader.rb', line 556 def fail_predicate log_error("Expected predicate (found: #{current_line.inspect})", lineno: lineno, exception: RDF::ReaderError) end |
#fail_subject (protected)
This method returns an undefined value.
Raises an “expected subject” parsing error on the current line.
547 548 549 |
# File 'lib/rdf/reader.rb', line 547 def fail_subject log_error("Expected subject (found: #{current_line.inspect})", lineno: lineno, exception: RDF::ReaderError) end |
#intern? ⇒ Boolean
Returns true
if parsed URIs should be interned.
626 627 628 |
# File 'lib/rdf/reader.rb', line 626 def intern? @options[:intern] end |
#lineno ⇒ Integer
Current line number being processed. For formats that can associate generated Statement with a particular line number from input, this value reflects that line number.
494 495 496 |
# File 'lib/rdf/reader.rb', line 494 def lineno @input.lineno end |
#prefix(name, uri) ⇒ RDF::URI #prefix(name) ⇒ RDF::URI Also known as: prefix!
Defines the given named URI prefix for this reader.
388 389 390 391 |
# File 'lib/rdf/reader.rb', line 388 def prefix(name, uri = nil) name = name.to_s.empty? ? nil : (name.respond_to?(:to_sym) ? name.to_sym : name.to_s.to_sym) uri.nil? ? prefixes[name] : prefixes[name] = uri end |
#prefixes ⇒ Hash{Symbol => RDF::URI}
Returns the URI prefixes currently defined for this reader.
352 353 354 |
# File 'lib/rdf/reader.rb', line 352 def prefixes @options[:prefixes] ||= {} end |
#prefixes=(prefixes) ⇒ Hash{Symbol => RDF::URI}
Defines the given URI prefixes for this reader.
367 368 369 |
# File 'lib/rdf/reader.rb', line 367 def prefixes=(prefixes) @options[:prefixes] = prefixes end |
#read_statement ⇒ RDF::Statement (protected)
Reads a statement from the input stream.
528 529 530 |
# File 'lib/rdf/reader.rb', line 528 def read_statement Statement.new(*read_triple) end |
#read_triple ⇒ Array(RDF::Term) (protected)
Reads a triple from the input stream.
538 539 540 |
# File 'lib/rdf/reader.rb', line 538 def read_triple raise NotImplementedError, "#{self.class}#read_triple" # override in subclasses end |
#rewind Also known as: rewind!
This method returns an undefined value.
Rewinds the input stream to the beginning of input.
472 473 474 |
# File 'lib/rdf/reader.rb', line 472 def rewind @input.rewind end |
#to_sym ⇒ Symbol
Returns a symbol appropriate to use with RDF::Reader.for()
261 262 263 |
# File 'lib/rdf/reader.rb', line 261 def to_sym self.class.to_sym end |
#valid? ⇒ Boolean
this parses the full input and is valid only in the reader block. Use Reader.new(input, validate: true)
if you intend to capture the result.
513 514 515 516 517 518 |
# File 'lib/rdf/reader.rb', line 513 def valid? super && !log_statistics[:error] rescue ArgumentError, RDF::ReaderError => e log_error(e.) false end |
#validate? ⇒ Boolean
Returns true
if parsed statements and values should be validated.
606 607 608 |
# File 'lib/rdf/reader.rb', line 606 def validate? @options[:validate] end |