Class: RDF::Tabular::Metadata

Inherits:
Object
  • Object
show all
Includes:
Utils
Defined in:
lib/rdf/tabular/metadata.rb

Direct Known Subclasses

Column, Dialect, Schema, Table, TableGroup, Transformation

Defined Under Namespace

Classes: DebugContext

Constant Summary collapse

INHERITED_PROPERTIES =

Inheritect properties, valid for all types

{
  null:               :atomic,
  lang:               :atomic,
  textDirection:      :atomic,
  separator:          :atomic,
  default:            :atomic,
  ordered:            :atomic,
  datatype:           :atomic,
  aboutUrl:           :uri_template,
  propertyUrl:        :uri_template,
  valueUrl:           :uri_template,
}.freeze
DATATYPES =

Valid datatypes

{
  anyAtomicType:      RDF::XSD.anySimpleType,
  anyURI:             RDF::XSD.anyURI,
  base64Binary:       RDF::XSD.basee65Binary,
  boolean:            RDF::XSD.boolean,
  byte:               RDF::XSD.byte,
  date:               RDF::XSD.date,
  dateTime:           RDF::XSD.dateTime,
  dateTimeDuration:   RDF::XSD.dateTimeDuration,
  dateTimeStamp:      RDF::XSD.dateTimeStamp,
  decimal:            RDF::XSD.decimal,
  double:             RDF::XSD.double,
  float:              RDF::XSD.float,
  ENTITY:             RDF::XSD.ENTITY,
  gDay:               RDF::XSD.gDay,
  gMonth:             RDF::XSD.gMonth,
  gMonthDay:          RDF::XSD.gMonthDay,
  gYear:              RDF::XSD.gYear,
  gYearMonth:         RDF::XSD.gYearMonth,
  hexBinary:          RDF::XSD.hexBinary,
  int:                RDF::XSD.int,
  integer:            RDF::XSD.integer,
  language:           RDF::XSD.language,
  long:               RDF::XSD.long,
  Name:               RDF::XSD.Name,
  NCName:             RDF::XSD.NCName,
  negativeInteger:    RDF::XSD.negativeInteger,
  nonNegativeInteger: RDF::XSD.nonNegativeInteger,
  nonPositiveInteger: RDF::XSD.nonPositiveInteger,
  normalizedString:   RDF::XSD.normalizedString,
  NOTATION:           RDF::XSD.NOTATION,
  positiveInteger:    RDF::XSD.positiveInteger,
  QName:              RDF::XSD.Qname,
  short:              RDF::XSD.short,
  string:             RDF::XSD.string,
  time:               RDF::XSD.time,
  token:              RDF::XSD.token,
  unsignedByte:       RDF::XSD.unsignedByte,
  unsignedInt:        RDF::XSD.unsignedInt,
  unsignedLong:       RDF::XSD.unsignedLong,
  unsignedShort:      RDF::XSD.unsignedShort,
  yearMonthDuration:  RDF::XSD.yearMonthDuration,

  any:                RDF::XSD.anySimpleType,
  binary:             RDF::XSD.base64Binary,
  datetime:           RDF::XSD.dateTime,
  html:               RDF.HTML,
  json:               RDF::Tabular::CSVW.JSON,
  number:             RDF::XSD.double,
  xml:                RDF.XMLLiteral,
}
NAME_SYNTAX =

A name is restricted according to the following RegExp.

Returns:

  • (RegExp) 
%r(\A(?:_col|[a-zA-Z0-9]|%\h\h)([a-zA-Z0-9\._]|%\h\h)*\z)
LOCAL_CONTEXT =

Local version of the context

Returns:

  • (JSON::LD::Context) 
::JSON::LD::Context.new.parse(File.expand_path("../../../../etc/csvw.jsonld", __FILE__))

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Utils

#depth

Constructor Details

#initialize(input, options = {}) ⇒ Metadata

Create Metadata from IO, Hash or String

Parameters:

  • input (Metadata, Hash, #read)
  • options (Hash{Symbol => Object}) (defaults to: {})

Options Hash (options):

  • :type (:TableGroup, :Table, :Transformation, :Schema, :Column, :Dialect) —

    Type of schema, if not set, intuited from properties

  • context (JSON::LD::Context) —

    Context used for this metadata. Taken from input if not provided

  • :base (RDF::URI) —

    The Base URL to use when expanding the document. This overrides the value of ‘input` if it is a URL. If not specified and `input` is not an URL, the base URL defaults to the current document URL if in a browser context, or the empty string if there is no document context.

Raises:



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# File 'lib/rdf/tabular/metadata.rb', line 265

def initialize(input, options = {})
  @options = options.dup

  # Get context from input
  # Optimize by using built-in version of context, and just extract @base, @lang
  @context = case input['@context']
  when Array then LOCAL_CONTEXT.parse(input['@context'].detect {|e| e.is_a?(Hash)} || {})
  when Hash  then LOCAL_CONTEXT.parse(input['@context'])
  when nil   then nil
  else            LOCAL_CONTEXT
  end

  reason = @options.delete(:reason)

  @options[:base] ||= @context.base if @context
  @options[:base] ||= input.base_uri if input.respond_to?(:base_uri)
  @options[:base] ||= input.filename if input.respond_to?(:filename)
  @options[:base] = RDF::URI(@options[:base])

  @context.base = @options[:base] if @context

  @options[:depth] ||= 0
  @filenames = Array(@options[:filenames]).map {|fn| RDF::URI(fn)} if @options[:filenames]
  @properties = self.class.const_get(:PROPERTIES)
  @required = self.class.const_get(:REQUIRED)

  @object = {}

  # Parent of this Metadata, if any
  @parent = @options[:parent]

  depth do
    # Input was parsed in .new
    # Metadata is object with symbolic keys
    input.each do |key, value|
      key = key.to_sym
      case key
      when :columns
        # An array of template specifications that provide mechanisms to transform the tabular data into other formats
        object[key] = if value.is_a?(Array) && value.all? {|v| v.is_a?(Hash)}
          number = 0
          value.map do |v|
            number += 1
            Column.new(v, @options.merge(table: (parent if parent.is_a?(Table)), parent: self, context: nil, number: number))
          end
        else
          # Invalid, but preserve value
          value
        end
      when :datatype
        # If in object form, normalize keys to symbols
        object[key] = case value
        when Hash
          value.inject({}) {|memo, (k,v)| memo[k.to_sym] = v; memo}
        else
          value
        end
      when :dialect
        # If provided, dialect provides hints to processors about how to parse the referenced file to create a tabular data model.
        object[key] = case value
        when String then Dialect.open(base.join(value), @options.merge(parent: self, context: nil))
        when Hash   then Dialect.new(value, @options.merge(parent: self, context: nil))
        else
          # Invalid, but preserve value
          value
        end
        @type ||= :Table
      when :resources
        # An array of table descriptions for the tables in the group.
        object[key] = if value.is_a?(Array) && value.all? {|v| v.is_a?(Hash)}
          value.map {|v| Table.new(v, @options.merge(parent: self, context: nil))}
        else
          # Invalid, but preserve value
          value
        end
      when :tableSchema
        # An object property that provides a schema description as described in section 3.8 Schemas, for all the tables in the group. This may be provided as an embedded object within the JSON metadata or as a URL reference to a separate JSON schema document
        # SPEC SUGGESTION: when loading a remote schema, assign @id from it's location if not already set
        object[key] = case value
        when String
          link = base.join(value).to_s
          s = Schema.open(link, @options.merge(parent: self, context: nil))
          s[:@id] ||= link
          s
        when Hash   then Schema.new(value, @options.merge(parent: self, context: nil))
        else
          # Invalid, but preserve value
          value
        end
      when :transformations
        # An array of template specifications that provide mechanisms to transform the tabular data into other formats
        object[key] = if value.is_a?(Array) && value.all? {|v| v.is_a?(Hash)}
          value.map {|v| Transformation.new(v, @options.merge(parent: self, context: nil))}
        else
          # Invalid, but preserve value
          value
        end
      when :url
        # URL of CSV relative to metadata
        object[:url] = value
        @url = base.join(value)
        @context.base = @url if @context # Use as base for expanding IRIs
      when :@id
        # metadata identifier
        object[:@id] = value
        @id = base.join(value)
      else
        if @properties.has_key?(key)
          self.send("#{key}=".to_sym, value)
        else
          object[key] = value
        end
      end
    end
  end

  # Set type from @type, if present and not otherwise defined
  @type ||= object[:@type].to_sym if object[:@type]
  if reason
    debug("md#initialize") {reason}
    debug("md#initialize") {"filenames: #{filenames}"}
    debug("md#initialize") {"#{inspect}, parent: #{!@parent.nil?}, context: #{!@context.nil?}"} unless is_a?(Dialect)
  end
end

Instance Attribute Details

#filenames ⇒ Array<RDF::URI> (readonly)

Filename(s) (URI) of opened metadata, if any May be plural when merged

Returns:

  • (Array<RDF::URI>) —

    filenames



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# File 'lib/rdf/tabular/metadata.rb', line 115

def filenames
  @filenames
end

#id ⇒ RDF::URI (readonly)

ID of this Metadata

Returns:

  • (RDF::URI) 


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# File 'lib/rdf/tabular/metadata.rb', line 102

def id
  @id
end

#object ⇒ Object

Hash representation



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# File 'lib/rdf/tabular/metadata.rb', line 23

def object
  @object
end

#parent ⇒ Metadata (readonly)

Parent of this Metadata (TableGroup for Table, …)

Returns:



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# File 'lib/rdf/tabular/metadata.rb', line 110

def parent
  @parent
end

#url ⇒ RDF::URI (readonly)

URL of related resource

Returns:

  • (RDF::URI) 


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# File 'lib/rdf/tabular/metadata.rb', line 106

def url
  @url
end

Class Method Details

.for_input(input, options = {}) ⇒ Metadata

Return metadata for a file, based on user-specified and path-relative locations from an input file

Parameters:

  • input (IO, StringIO)
  • options (Hash{Symbol => Object}) (defaults to: {})

Options Hash (options):

  • :metadata (Metadata, Hash, String, RDF::URI) —

    user supplied metadata, merged on top of extracted metadata. If provided as a URL, Metadata is loade from that location

  • :base (RDF::URI) —

    The Base URL to use when expanding the document. This overrides the value of ‘input` if it is a URL. If not specified and `input` is not an URL, the base URL defaults to the current document URL if in a browser context, or the empty string if there is no document context.

Returns:



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# File 'lib/rdf/tabular/metadata.rb', line 143

def self.for_input(input, options = {})
  base = options[:base]

  # Use user metadata
  user_metadata = case options[:metadata]
  when Metadata then options[:metadata]
  when Hash
    Metadata.new(options[:metadata], options.merge(reason: "load user metadata: #{options[:metadata].inspect}"))
  when String, RDF::URI
    Metadata.open(options[:metadata], options.merge(filenames: options[:metadata], reason: "load user metadata: #{options[:metadata].inspect}"))
  end

  found_metadata = nil

  # If user_metadata does not describe input, get the first found from linked-, file-, and directory-specific metadata
  unless user_metadata.is_a?(Table) || user_metadata.is_a?(TableGroup) && user_metadata.for_table(base)
    # load link metadata, if available
    locs = []
    if input.respond_to?(:links) && 
      link = input.links.find_link(%w(rel describedby))
      locs << RDF::URI(base).join(link.href)
    end

    if base
      locs += [RDF::URI("#{base}-metadata.json"), RDF::URI(base).join("metadata.json")]
    end

    locs.each do |loc|
      found_metadata ||= begin
        Metadata.open(loc, options.merge(filenames: loc, reason: "load found metadata: #{loc}"))
      rescue
        debug("for_input", options) {"failed to load found metadata #{loc}: #{$!}"}
        nil
      end
    end
  end

  # Return either the merge or user- and found-metadata, any of these, or an empty TableGroup
  metadata = case
  when user_metadata && found_metadata then user_metadata.merge(found_metadata)
  when user_metadata then user_metadata
  when found_metadata then found_metadata
  else TableGroup.new({resources: [{url: base}]}, options)
  end

  # Make TableGroup, if not already
  metadata.is_a?(TableGroup) ? metadata : metadata.merge(TableGroup.new({}))
end

.new(input, options = {}) ⇒ Object 



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# File 'lib/rdf/tabular/metadata.rb', line 194

def self.new(input, options = {})
  # Triveal case
  return input if input.is_a?(Metadata)

  object = case input
  when Hash then input
  when IO, StringIO then ::JSON.parse(input.read)
  else ::JSON.parse(input.to_s)
  end

  unless options[:parent]
    # Add context, if not set (which it should be)
    object['@context'] ||= options.delete(:@context) || options[:context] || 'http://www.w3.org/ns/csvw'
  end

  klass = case
    when !self.equal?(RDF::Tabular::Metadata)
      self # subclasses can be directly constructed without type dispatch
    else
      type = if options[:type]
        type = options[:type].to_sym
        raise Error, "If provided, type must be one of :TableGroup, :Table, :Transformation, :Schema, :Column, :Dialect]" unless
          [:TableGroup, :Table, :Transformation, :Schema, :Column, :Dialect].include?(type)
        type
      end

      # Figure out type by @type
      type ||= object['@type']

      # Figure out type by site
      object_keys = object.keys.map(&:to_s)
      type ||= case
      when %w(resources).any? {|k| object_keys.include?(k)} then :TableGroup
      when %w(dialect tableSchema transformations).any? {|k| object_keys.include?(k)} then :Table
      when %w(targetFormat scriptFormat source).any? {|k| object_keys.include?(k)} then :Transformation
      when %w(columns primaryKey foreignKeys urlTemplate).any? {|k| object_keys.include?(k)} then :Schema
      when %w(name required).any? {|k| object_keys.include?(k)} then :Column
      when %w(commentPrefix delimiter doubleQuote encoding header headerColumnCount headerRowCount).any? {|k| object_keys.include?(k)} then :Dialect
      when %w(lineTerminator quoteChar skipBlankRows skipColumns skipInitialSpace skipRows trim).any? {|k| object_keys.include?(k)} then :Dialect
      end

      case type.to_s.to_sym
      when :TableGroup then RDF::Tabular::TableGroup
      when :Table then RDF::Tabular::Table
      when :Transformation then RDF::Tabular::Transformation
      when :Schema then RDF::Tabular::Schema
      when :Column then RDF::Tabular::Column
      when :Dialect then RDF::Tabular::Dialect
      else
        raise Error, "Unkown metadata type: #{type.inspect}"
      end
    end

  md = klass.allocate
  md.send(:initialize, object, options)
  md
end

.open(path, options = {}) ⇒ Object

Attempt to retrieve the file at the specified path. If it is valid metadata, create a new Metadata object from it, otherwise, an empty Metadata object

Parameters:

  • path (String)
  • options (Hash{Symbol => Object}) (defaults to: {}) —

    see ‘RDF::Util::File.open_file` in RDF.rb



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# File 'lib/rdf/tabular/metadata.rb', line 123

def self.open(path, options = {})
  options = options.merge(
    headers: {
      'Accept' => 'application/ld+json, application/json'
    }
  )
  path = "file:" + path unless path =~ /^\w+:/
  RDF::Util::File.open_file(path, options) do |file|
    self.new(file, options.merge(base: path, filenames: path))
  end
end

Instance Method Details

#==(other) ⇒ Object 



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# File 'lib/rdf/tabular/metadata.rb', line 1087

def ==(other)
  object == (other.is_a?(Hash) ? other : other.object)
end

#[](key) ⇒ Object

Proxy to @object



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# File 'lib/rdf/tabular/metadata.rb', line 1084

def [](key); object[key]; end

#[]=(key, value) ⇒ Object 



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# File 'lib/rdf/tabular/metadata.rb', line 1085

def []=(key, value); object[key] = value; end

#base ⇒ RDF::URI

Base URL of metadata

Returns:

  • (RDF::URI) 


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# File 'lib/rdf/tabular/metadata.rb', line 446

def base; @options[:base]; end

#common_properties(subject, property, value) {|property, statement| ... } ⇒ Object #common_properties(subject, property, value) ⇒ String, ...

Return JSON-friendly or yield RDF for common properties

Overloads:

  • #common_properties(subject, property, value) {|property, statement| ... } ⇒ Object

    Yield RDF statements

    Parameters:

    • subject (RDF::Resource)
    • property (String)
    • value (String, Hash{String => Object}, Array<String, Hash{String => Object}>)

    Yields:

    • property, value

    Yield Parameters:

    • property (String) —

      as a PName or URL

    • statement (RDF::Statement)
  • #common_properties(subject, property, value) ⇒ String, ...

    Return value with expanded values and node references flattened

    Returns:

    • (String, Hash{String => Object}, Array<String, Hash{String => Object}>) —

      simply extracted from metadata



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# File 'lib/rdf/tabular/metadata.rb', line 813

def common_properties(subject, property, value, &block)
  if block_given?
    property = context.expand_iri(property.to_s, vocab: true) unless property.is_a?(RDF::URI)
    case value
    when Array
      value.each {|v| common_properties(subject, property, v, &block)}
    when Hash
      if value['@value']
        dt = RDF::URI(context.expand_iri(value['@type'], vocab: true)) if value['@type']
        lit = RDF::Literal(value['@value'], language: value['@language'], datatype: dt)
        block.call(RDF::Statement.new(subject, property, lit))
      else
        # value MUST be a node object, establish a new subject from `@id`
        s2 = value.has_key?('@id') ? context.expand_iri(value['@id']) : RDF::Node.new

        # Generate a triple
        block.call(RDF::Statement.new(subject, property, s2))

        # Generate types
        Array(value['@type']).each do |t|
          block.call(RDF::Statement.new(s2, RDF.type, context.expand_iri(t, vocab: true)))
        end

        # Generate triples for all other properties
        value.each do |prop, val|
          next if prop.to_s.start_with?('@')
          common_properties(s2, prop, val, &block)
        end
      end
    else
      # Value is a primitive JSON value
      lit = RDF::Literal(value)
      block.call(RDF::Statement.new(subject, property, RDF::Literal(value)))
    end
  else
    case value
    when Array
      value.map {|v| common_properties(subject, property, v)}
    when Hash
      if value['@value']
        value['@value']
      elsif value.keys == %w(@id) && value['@id']
        value['@id']
      else
        nv = {}
        value.each do |k, v|
          case k.to_s
          when '@id' then nv[k.to_s] = context.expand_iri(v['@id']).to_s
          when '@type' then nv[k.to_s] = v
          else nv[k.to_s] = common_properties(nil, k, v)
          end
        end
        nv
      end
    else
      value
    end
  end
end

#context ⇒ JSON::LD::Context

Context used for this metadata. Use parent’s if not defined on self.

Returns:

  • (JSON::LD::Context) 


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# File 'lib/rdf/tabular/metadata.rb', line 399

def context
  @context || (parent.context if parent)
end

#dialect ⇒ Dialect

Treat ‘dialect` similar to an inherited property, but merge together values from Table and TableGroup

Returns:



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# File 'lib/rdf/tabular/metadata.rb', line 405

def dialect
  @dialect ||= case
  when object[:dialect] then object[:dialect]
  when parent then parent.dialect
  when is_a?(Table) || is_a?(TableGroup)
    d = Dialect.new({}, @options.merge(parent: self, context: nil))
    self.dialect = d unless self.parent
    d
  else
    raise Error, "Can't access dialect from #{self.class} without a parent"
  end
end

#dialect=(value) ⇒ Dialect

Set new dialect

Returns:



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# File 'lib/rdf/tabular/metadata.rb', line 420

def dialect=(value)
  # Clear cached dialect information from children
  object.values.each do |v|
    case v
    when Metadata then v.object.delete(:dialect)
    when Array then v.each {|vv| vv.object.delete(:dialect) if vv.is_a?(Metadata)}
    end
  end

  if value.is_a?(Hash)
    @dialect = object[:dialect] = Dialect.new(value)
  elsif value
    # Remember invalid dialect for validation purposes
    object[:dialect] = value
  else
    object.delete(:dialect)
    @dialect = nil
  end
end

#each(&block) ⇒ Object 



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# File 'lib/rdf/tabular/metadata.rb', line 1086

def each(&block); object.each(&block); end

#each_row(input) {|Row| ... } ⇒ Object

Yield each data row from the input file

Parameters:

  • input (:read)

Yields:



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# File 'lib/rdf/tabular/metadata.rb', line 774

def each_row(input)
  csv = ::CSV.new(input, csv_options)
  # Skip skipRows and headerRowCount
  number, skipped = 0, (dialect.skipRows.to_i + dialect.headerRowCount)
  (1..skipped).each {csv.shift}
  csv.each do |data|
    # Check for embedded comments
    if dialect.commentPrefix && data.first.to_s.start_with?(dialect.commentPrefix)
      v = data.join(' ')[1..-1].strip
      unless v.empty?
        (self["rdfs:comment"] ||= []) << v
        yield RDF::Statement.new(nil, RDF::RDFS.comment, RDF::Literal(v))
      end
      skipped += 1
      next
    elsif dialect.skipBlankRows && data.join("").strip.empty?
      skipped += 1
      next
    end
    number += 1
    yield(Row.new(data, self, number, number + skipped))
  end
end

#errors ⇒ Array<String>

Validation errors

Returns:

  • (Array<String>) 


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# File 'lib/rdf/tabular/metadata.rb', line 460

def errors
  validate! && []
rescue Error => e
  e.message.split("\n")
end

#has_annotations? ⇒ Boolean

Does the Metadata have any common properties?

Returns:

  • (Boolean) 


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# File 'lib/rdf/tabular/metadata.rb', line 875

def has_annotations?
  object.keys.any? {|k| k.to_s.include?(':')}
end

#inspect ⇒ Object 



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# File 'lib/rdf/tabular/metadata.rb', line 1079

def inspect
  self.class.name + object.inspect
end

#merge(*metadata) ⇒ Metadata

Merge metadata into this a copy of this metadata

Parameters:

Returns:



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# File 'lib/rdf/tabular/metadata.rb', line 882

def merge(*metadata)
  return self if metadata.empty?
  # If the top-level object of any of the metadata files are table descriptions, these are treated as if they were table group descriptions containing a single table description (ie having a single resource property whose value is the same as the original table description).
  this = case self
  when TableGroup then self.dup
  when Table
    if self.is_a?(Table) && self.parent
      self.parent
    else
      content = {"@type" => "TableGroup", "resources" => [self]}
      content['@context'] = object.delete(:@context) if object[:@context]
      ctx = @context
      self.remove_instance_variable(:@context) if self.instance_variables.include?(:@context)
      tg = TableGroup.new(content, filenames: @filenames, base: base)
      @parent = tg  # Link from parent
      tg
    end
  else self.dup
  end

  # Merge all passed metadata into this
  merged = metadata.reduce(this) do |memo, md|
    md = case md
    when TableGroup then md
    when Table
      if md.parent
        md.parent
      else
        content = {"@type" => "TableGroup", "resources" => [md]}
        ctx = md.context
        content['@context'] = md.object.delete(:@context) if md.object[:@context]
        md.remove_instance_variable(:@context) if md.instance_variables.include?(:@context) 
        tg = TableGroup.new(content, filenames: md.filenames, base: md.base)
        md.instance_variable_set(:@parent, tg)  # Link from parent
        tg
      end
    else
      md
    end

    raise "Can't merge #{memo.class} with #{md.class}" unless memo.class == md.class

    memo.merge!(md)
  end

  # Set @context of merged
  merged[:@context] = 'http://www.w3.org/ns/csvw'
  merged
end

#merge!(metadata) ⇒ Object

Merge metadata into self



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# File 'lib/rdf/tabular/metadata.rb', line 933

def merge!(metadata)
  raise "Merging non-equivalent metadata types: #{self.class} vs #{metadata.class}" unless self.class == metadata.class

  depth do
    # Merge filenames
    if @filenames || metadata.filenames
      @filenames = (Array(@filenames) | Array(metadata.filenames)).uniq
    end

    # Normalize A (this) and B (metadata) values into normal form
    self.normalize!
    metadata = metadata.dup.normalize!

    @dialect = nil  # So that it is re-built when needed
    # Merge each property from metadata into self
    metadata.each do |key, value|
      case @properties[key]
      when :array
        # If the property is an array property, the way in which values are merged depends on the property; see the relevant property for this definition.
        object[key] = case object[key]
        when nil then []
        when Hash then [object[key]]  # Shouldn't happen if well formed
        else object[key]
        end

        value = [value] if value.is_a?(Hash)
        case key
        when :notes
          # If the property is notes, the result is an array containing values from A followed by values from B.
          a = object[key].is_a?(Array) ? object[key] : [object[key]].compact
          b = value.is_a?(Array) ? value : [value]
          object[key] = a + b
        when :resources
          # When an array of table descriptions B is imported into an original array of table descriptions A, each table description within B is combined into the original array A by:
          value.each do |tb|
            if ta = object[key].detect {|e| e.url == tb.url}
              # if there is a table description with the same url in A, the table description from B is imported into the matching table description in A
              debug("merge!: resources") {"TA: #{ta.inspect}, TB: #{tb.inspect}"}
              ta.merge!(tb)
            else
              # otherwise, the table description from B is appended to the array of table descriptions A
              tb = tb.dup
              tb.instance_variable_set(:@parent, self)
              debug("merge!: resources") {"add TB: #{tb.inspect}"}
              object[key] << tb
            end
          end
        when :transformations
          # SPEC CONFUSION: differing transformations with same @id?
          # When an array of template specifications B is imported into an original array of template specifications A, each template specification within B is combined into the original array A by:
          value.each do |t|
            if ta = object[key].detect {|e| e.targetFormat == t.targetFormat && e.scriptFormat == t.scriptFormat}
              # if there is a template specification with the same targetFormat and scriptFormat in A, the template specification from B is imported into the matching template specification in A
              ta.merge!(t)
            else
              # otherwise, the template specification from B is appended to the array of template specifications A
              t = t.dup
              t.instance_variable_set(:@parent, self) if self
              object[key] << t
            end
          end
        when :columns
          # When an array of column descriptions B is imported into an original array of column descriptions A, each column description within B is combined into the original array A by:
          Array(value).each_with_index do |cb, index|
            ca = object[key][index] || {}
            va = ([ca[:name]] + (ca[:title] || {}).values.flatten).compact.map(&:downcase)
            vb = ([cb[:name]] + (cb[:title] || {}).values.flatten).compact.map(&:downcase)
            if !(va & vb).empty?
              debug("merge!: columns") {"index: #{index}, va: #{va}, vb: #{vb}"}
              # If there's a non-empty case-insensitive intersection between the name and title values for the column description at the same index within A and B, the column description from B is imported into the matching column description in A
              ca.merge!(cb)
            elsif ca.nil? && cb.virtual
              debug("merge!: columns") {"index: #{index}, virtual"}
              # otherwise, if at a given index there is no column description within A, but there is a column description within B.
              cb = cb.dup
              cb.instance_variable_set(:@parent, self) if self
              object[key][index] = cb
            else
              debug("merge!: columns") {"index: #{index}, ignore"}
              raise Error, "Columns at same index don't match: #{ca.to_json} vs. #{cb.to_json}"
            end
          end
          # The number of non-virtual columns in A and B MUST be the same
          nA = object[key].reject(&:virtual).length
          nB = Array(value).reject(&:virtual).length
          raise Error, "Columns must have the same number of non-virtual columns" unless nA == nB || nB == 0
        when :foreignKeys
          # When an array of foreign key definitions B is imported into an original array of foreign key definitions A, each foreign key definition within B which does not appear within A is appended to the original array A.
          # SPEC CONFUSION: If definitions vary only a little, they should probably be merged (e.g. common properties).
          object[key] = object[key] + (metadata[key] - object[key])
        end
      when :object
        case key
        when :notes
          # If the property accepts arrays, the result is an array of objects or strings: those from A followed by those from B that were not already a value in A.
          a = object[key] || []
          object[key] = (a + value).uniq
        else
          # if the property only accepts single objects
          if object[key].is_a?(String) || value.is_a?(String)
            # if the value of the property in A is a string or the value from B is a string then the value from A overrides that from B
            object[key] ||= value
          elsif object[key].is_a?(Metadata)
            # otherwise (if both values as objects) the objects are merged as described here
            object[key].merge!(value)
          elsif object[key].is_a?(Hash)
            # otherwise (if both values as objects) the objects are merged as described here
            object[key].merge!(value)
          else
            value = value.dup
            value.instance_variable_set(:@parent, self) if self
            object[key] = value
          end
        end
      when :natural_language
        # If the property is a natural language property, the result is an object whose properties are language codes and where the values of those properties are arrays. The suitable language code for the values is either explicit within the existing value or determined through the default language in the metadata document; if it can't be determined the language code und should be used. The arrays should provide the values from A followed by those from B that were not already a value in A.
        a = object[key] || {}
        b = value
        debug("merge!: natural_language") {
          "A: #{a.inspect}, B: #{b.inspect}"
        }
        b.each do |k, v|
          a[k] = Array(a[k]) + (Array(b[k]) - Array(a[k]))
        end
        # eliminate titles with no language where the same string exists with a language
        if a.has_key?("und")
          a["und"] = a["und"].reject do |v|
            a.any? {|lang, values| lang != 'und' && values.include?(v)}
          end
          a.delete("und") if a["und"].empty?
        end
        object[key] = a
      when ->(k) {key == :@id}
        object[key] ||= value
        @id ||= metadata.id
      else
        # Otherwise, the value from A overrides that from B
        object[key] ||= value
      end
    end
  end

  debug("merge!") {self.inspect}
  self
end

#normalize! ⇒ self

Normalize object

Returns:

  • (self)

Raises:



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# File 'lib/rdf/tabular/metadata.rb', line 1096

def normalize!
  self.each do |key, value|
    self[key] = case @properties[key] || INHERITED_PROPERTIES[key]
    when ->(k) {key.to_s.include?(':') || key == :notes}
      normalize_jsonld(key, value)
    when ->(k) {key.to_s == '@context'}
      "http://www.w3.org/ns/csvw"
    when :link
      base.join(value).to_s
    when :array
      value = [value] unless value.is_a?(Array)
      value.map do |v|
        if v.is_a?(Metadata)
          v.normalize!
        elsif v.is_a?(Hash) && (ref = v["reference"]).is_a?(Hash)
          # SPEC SUGGESTION: special case for foreignKeys
          ref["resource"] = base.join(ref["resource"]).to_s if ref["resource"]
          ref["schemaReference"] = base.join(ref["schemaReference"]).to_s if ref["schemaReference"]
          v
        else
          v
        end
      end
    when :object
      case value
      when Metadata then value.normalize!
      when String
        # Load referenced JSON document
        # (This is done when objects are loaded in this implementation)
        raise "unexpected String value of property '#{key}': #{value}"
      else value
      end
    when :natural_language
      value.is_a?(Hash) ? value : {(context.default_language || 'und') => Array(value)}
    when :atomic
      case key
      when :datatype then normalize_datatype(value)
      else                value
      end
    else
      value
    end
  end
  self
end

#normalize_datatype(value) ⇒ Hash{Symbol => String}

Normalize datatype to Object/Hash representation

Parameters:

  • value (String, Hash{Symbol => String})

Returns:

  • (Hash{Symbol => String}) 


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# File 'lib/rdf/tabular/metadata.rb', line 1146

def normalize_datatype(value)
  # Normalize datatype to array of object form
  value = {base: value} unless value.is_a?(Hash)
  # Create a new representation using symbols and transformed values
  nv = {}
  value.each do |kk, vv|
    case kk.to_sym
    when :base, :decimalChar, :format, :groupChar, :pattern then nv[kk.to_sym] = vv
    when :length, :minLength, :maxLength, :minimum, :maximum,
      :minInclusive, :maxInclusive, :minExclusive, :maxExclusive
      nv[kk.to_sym] = vv.to_i
    end
  end
  nv[:base] ||= 'string'
  nv
end

#normalize_jsonld(property, value) ⇒ String, ...

Normalize JSON-LD

Also, raise error if invalid JSON-LD dialect is detected

Parameters:

  • property (Symbol, String)
  • value (String, Hash{String => Object}, Array<String, Hash{String => Object}>)

Returns:

  • (String, Hash{String => Object}, Array<String, Hash{String => Object}>) 


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# File 'lib/rdf/tabular/metadata.rb', line 1171

def normalize_jsonld(property, value)
  case value
  when Array
    value.map {|v| normalize_jsonld(property, v)}
  when String
    ev = {'@value' => value}
    ev['@language'] = context.default_language if context.default_language
    ev
  when Hash
    if value['@value']
      if !(value.keys.sort - %w(@value @type @language)).empty?
        raise Error, "Value object may not contain keys other than @value, @type, or @language: #{value.to_json}"
      elsif (value.keys.sort & %w(@language @type)) == %w(@language @type)
        raise Error, "Value object may not contain both @type and @language: #{value.to_json}"
      elsif value['@language'] && !BCP47::Language.identify(value['@language'])
        raise Error, "Value object with @language must use valid language: #{value.to_json}"
      elsif value['@type'] && !context.expand_iri(value['@type'], vocab: true).absolute?
        raise Error, "Value object with @type must defined type: #{value.to_json}"
      end
      value
    else
      nv = {}
      value.each do |k, v|
        case k
        when "@id"
          nv[k] = context.expand_iri(v, documentRelative: true).to_s
          raise Error, "Invalid use of explicit BNode on @id" if nv[k].start_with?('_:')
        when "@type"
          Array(v).each do |vv|
            # Validate that all type values transform to absolute IRIs
            resource = context.expand_iri(vv, vocab: true)
            raise Error, "Invalid type #{vv} in JSON-LD context" unless resource.uri? && resource.absolute?
          end
          nv[k] = v
        when /^(@|_:)/
          raise Error, "Invalid use of #{k} in JSON-LD content"
        else
          nv[k] = normalize_jsonld(k, v)
        end
      end
      nv
    end
  else
    value
  end
end

#to_json(args = nil) ⇒ Object 



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# File 'lib/rdf/tabular/metadata.rb', line 1090

def to_json(args=nil); object.to_json(args); end

#type ⇒ :TableGroup, ...

Type of this Metadata

Returns:

  • (:TableGroup, :Table, :Transformation, :Schema, :Column) 


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# File 'lib/rdf/tabular/metadata.rb', line 442

def type; self.class.name.split('::').last.to_sym; end

#valid? ⇒ Boolean

Do we have valid metadata?

Returns:

  • (Boolean) 


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# File 'lib/rdf/tabular/metadata.rb', line 450

def valid?
  validate!
  true
rescue
  false
end

#valid_inherited_property?(key, value) { ... } ⇒ Boolean

Determine if an inherited property is valid

Parameters:

  • value (String, Array<String>, Hash{String => String})

Yields:

  • message error message

Returns:

  • (Boolean) 


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# File 'lib/rdf/tabular/metadata.rb', line 715

def valid_inherited_property?(key, value)
  pv = parent.send(key) if parent
  error = case key
  when :aboutUrl, :default, :propertyUrl, :valueUrl
    "string" unless value.is_a?(String)
  when :datatype
    # Normalization usually redundant
    dt = normalize_datatype(value)
    # FIXME: support arrays of datatypes?
    "valid datatype" unless DATATYPES.keys.map(&:to_s).include?(dt[:base]) || RDF::URI(dt[:base]).absolute?
  when :lang
    "valid BCP47 language tag" unless BCP47::Language.identify(value.to_s)
  when :null
    # To be valid, it must be a string or array, and must be compatible with any inherited value through being a subset
    "string or array of strings" unless !value.is_a?(Hash) && Array(value).all? {|v| v.is_a?(String)}
  when :ordered
    "boolean" unless value.is_a?(TrueClass) || value.is_a?(FalseClass)
  when :separator
    "single character" unless value.nil? || value.is_a?(String) && value.length == 1
  when :textDirection
    # A value for this property is compatible with an inherited value only if they are identical.
    "rtl or ltr" unless %(rtl ltr).include?(value)
  end ||

  case key
    # Compatibility
  when :aboutUrl, :propertyUrl, :valueUrl
    # No restrictions
  when :default, :ordered, :separator, :textDirection
    "same as that defined on parent" if pv && pv != value
  when :datatype
    if pv
      # Normalization usually redundant
      dt = normalize_datatype(value)
      pvdt = normalize_datatype(pv)
      vl = RDF::Literal.new("", datatype: DATATYPES[dt[:base].to_sym])
      pvvl = RDF::Literal.new("", datatype: DATATYPES[pvdt[:base].to_sym])
      # must be a subclass of some type defined on parent
      "compatible datatype of that defined on parent" unless vl.is_a?(pvvl.class)
    end
  when :lang
    "lang expected to restrict #{pv}" if pv && !value.start_with?(pv)
  when :null
    "subset of that defined on parent" if pv && (Array(value) & Array(pv)) != Array(value)
  end

  if error
    yield "#{type} has invalid property '#{key}' ('#{value}'): expected #{error}"
    false
  else
    true
  end
end

#valid_natural_language_property?(key, value) { ... } ⇒ Boolean

Determine if a natural language property is valid

Parameters:

  • value (String, Array<String>, Hash{String => String})

Yields:

  • message error message

Returns:

  • (Boolean) 


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# File 'lib/rdf/tabular/metadata.rb', line 703

def valid_natural_language_property?(key, value)
  unless value.is_a?(Hash) && value.all? {|k, v| Array(v).all? {|vv| vv.is_a?(String)}}
    yield "#{type} has invalid property '#{key}': #{value.inspect}, expected a valid natural language property" if block_given?
    false
  end
end

#validate! ⇒ self

Validate metadata, raising an error containing all errors detected during validation

Returns:

  • (self)

Raises:

  • (Error) —

    Raise error if metadata has any unexpected properties



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# File 'lib/rdf/tabular/metadata.rb', line 470

def validate!
  expected_props, required_props = @properties.keys, @required
  errors = []

  unless is_a?(Dialect) || is_a?(Transformation)
    expected_props = expected_props + INHERITED_PROPERTIES.keys
  end

  # It has only expected properties (exclude metadata)
  check_keys = object.keys - [:"@id", :"@context"]
  check_keys = check_keys.reject {|k| k.to_s.include?(':')} unless is_a?(Dialect)
  errors << "#{type} has unexpected keys: #{(check_keys - expected_props).map(&:to_s)}" unless check_keys.all? {|k| expected_props.include?(k)}

  # It has required properties
  errors << "#{type} missing required keys: #{(required_props & check_keys).map(&:to_s)}"  unless (required_props & check_keys) == required_props

  # Every property is valid
  object.keys.each do |key|
    value = object[key]
    case key
    when :aboutUrl, :datatype, :default, :lang, :null, :ordered, :propertyUrl, :separator, :textDirection, :valueUrl
      valid_inherited_property?(key, value) {|m| errors << m}
    when :columns
      if value.is_a?(Array) && value.all? {|v| v.is_a?(Column)}
        value.each do |v|
          begin
            v.validate!
          rescue Error => e
            errors << e.message
          end
        end
        column_names = value.map(&:name)
        errors << "#{type} has invalid property '#{key}': must have unique names: #{column_names.inspect}" unless column_names.uniq == column_names
      else
        errors << "#{type} has invalid property '#{key}': expected array of Columns"
      end
    when :commentPrefix, :delimiter, :quoteChar
      unless value.is_a?(String) && value.length == 1
        errors << "#{type} has invalid property '#{key}': #{value.inspect}, expected a single character string"
      end
    when :format, :lineTerminator, :uriTemplate
      unless value.is_a?(String)
        errors << "#{type} has invalid property '#{key}': #{value.inspect}, expected a string"
      end
    when :dialect
      unless value.is_a?(Dialect)
        errors << "#{type} has invalid property '#{key}': expected a Dialect Description"
      end
      begin
        value.validate! if value
      rescue Error => e
        errors << e.message
      end
    when :doubleQuote, :header, :required, :skipInitialSpace, :skipBlankRows, :suppressOutput, :virtual
      unless value.is_a?(TrueClass) || value.is_a?(FalseClass)
        errors << "#{type} has invalid property '#{key}': #{value}, expected boolean true or false"
      end
    when :encoding
      unless (Encoding.find(value) rescue false)
        errors << "#{type} has invalid property '#{key}': #{value.inspect}, expected a valid encoding"
      end
    when :foreignKeys
      # An array of foreign key definitions that define how the values from specified columns within this table link to rows within this table or other tables. A foreign key definition is a JSON object with the properties:
      value.is_a?(Array) && value.each do |fk|
        if fk.is_a?(Hash)
          columnReference, reference = fk['columnReference'], fk['reference']
          errors << "#{type} has invalid property '#{key}': missing columnReference and reference" unless columnReference && reference
          errors << "#{type} has invalid property '#{key}': has extra entries #{fk.keys.inspect}" unless fk.keys.length == 2

          # Verify that columns exist in this schema
          Array(columnReference).each do |k|
            errors << "#{type} has invalid property '#{key}': columnReference not found #{k}" unless self.columns.any? {|c| c.name == k}
          end

          if reference.is_a?(Hash)
            ref_cols = reference['columnReference']
            schema = if reference.has_key?('resource')
              if reference.has_key?('schemaReference')
                errors << "#{type} has invalid property '#{key}': reference has a schemaReference: #{reference.inspect}" 
              end
              # resource is the URL of a Table in the TableGroup
              ref = base.join(reference['resource']).to_s
              table = root.is_a?(TableGroup) && root.resources.detect {|t| t.url == ref}
              errors << "#{type} has invalid property '#{key}': table referenced by #{ref} not found" unless table
              table.tableSchema if table
            elsif reference.has_key?('schemaReference')
              # resource is the @id of a Schema in the TableGroup
              ref = base.join(reference['schemaReference']).to_s
              tables = root.is_a?(TableGroup) ? root.resources.select {|t| t.tableSchema[:@id] == ref} : []
              case tables.length
              when 0
                errors << "#{type} has invalid property '#{key}': schema referenced by #{ref} not found"
                nil
              when 1
                tables.first.tableSchema
              else
                errors << "#{type} has invalid property '#{key}': multiple schemas found from #{ref}"
                nil
              end
            end

            if schema
              # ref_cols must exist in schema
              Array(ref_cols).each do |k|
                errors << "#{type} has invalid property '#{key}': column reference not found #{k}" unless schema.columns.any? {|c| c.name == k}
              end
            end
          else
            errors << "#{type} has invalid property '#{key}': reference must be an object #{reference.inspect}"
          end
        else
          errors << "#{type} has invalid property '#{key}': reference must be an object: #{reference.inspect}" 
        end
      end
    when :headerColumnCount, :headerRowCount, :skipColumns, :skipRows
      unless value.is_a?(Numeric) && value.integer? && value > 0
        errors << "#{type} has invalid property '#{key}': #{value.inspect} must be a positive integer"
      end
    when :length, :minLength, :maxLength
      unless value.is_a?(Numeric) && value.integer? && value > 0
        errors << "#{type} has invalid property '#{key}': #{value.inspect}, expected a positive integer"
      end
      unless key == :length || value != object[:length]
        # Applications must raise an error if length, maxLength or minLength are specified and the cell value is not a list (ie separator is not specified), a string or one of its subtypes, or a binary value.
        errors << "#{type} has invalid property '#{key}': Use of both length and #{key} requires they be equal"
      end
    when :minimum, :maximum, :minInclusive, :maxInclusive, :minExclusive, :maxExclusive
      unless value.is_a?(Numeric) ||
        RDF::Literal::Date.new(value.to_s).valid? ||
        RDF::Literal::Time.new(value.to_s).valid? ||
        RDF::Literal::DateTime.new(value.to_s).valid?
        errors << "#{type} has invalid property '#{key}': #{value}, expected numeric or valid date/time"
      end
    when :name
      unless value.is_a?(String) && name.match(NAME_SYNTAX)
        errors << "#{type} has invalid property '#{key}': #{value}, expected proper name format"
      end
    when :notes
      unless value.is_a?(Hash) || value.is_a?(Array)
        errors << "#{type} has invalid property '#{key}': #{value}, Object or Array"
      end
      begin
        normalize_jsonld(key, value)
      rescue Error => e
        errors << "#{type} has invalid content '#{key}': #{e.message}"
      end
    when :primaryKey
      # A column reference property that holds either a single reference to a column description object or an array of references.
      Array(value).each do |k|
        errors << "#{type} has invalid property '#{key}': column reference not found #{k}" unless self.columns.any? {|c| c.name == k}
      end
    when :resources
      if value.is_a?(Array) && value.all? {|v| v.is_a?(Table)}
        value.each do |t|
          begin
            t.validate!
          rescue Error => e
            errors << e.message
          end
        end
      else
        errors << "#{type} has invalid property '#{key}': expected array of Tables"
      end
    when :scriptFormat, :targetFormat
      unless RDF::URI(value).valid?
        errors << "#{type} has invalid property '#{key}': #{value.inspect}, expected valid absolute URL"
      end
    when :source
      unless %w(json rdf).include?(value) || value.nil?
        errors << "#{type} has invalid property '#{key}': #{value.inspect}, expected json or rdf"
      end
    when :tableDirection
      unless %w(rtl ltr default).include?(value)
        errors << "#{type} has invalid property '#{key}': #{value.inspect}, expected rtl, ltr, or default"
      end
    when :tableSchema
      if value.is_a?(Schema)
        begin
          value.validate!
        rescue Error => e
          errors << e.message
        end
      else
        errors << "#{type} has invalid property '#{key}': expected Schema"
      end
    when :transformations
      if value.is_a?(Array) && value.all? {|v| v.is_a?(Transformation)}
        value.each do |t|
          begin
            t.validate!
          rescue Error => e
            errors << e.message
          end
        end
      else
        errors << "#{type} has invalid property '#{key}': expected array of Transformations"
      end
    when :title
      valid_natural_language_property?(:title, value) {|m| errors << m}
    when :trim
      unless %w(true false 1 0 start end).include?(value.to_s.downcase)
        errors << "#{type} has invalid property '#{key}': #{value.inspect}, expected true, false, 1, 0, start or end"
      end
    when :url
      unless @url.valid?
        errors << "#{type} has invalid property '#{key}': #{value.inspect}, expected valid absolute URL"
      end
    when :@id, :@context
      # Skip these
    when :@type
      unless value.to_sym == type
        errors << "#{type} has invalid property '#{key}': #{value.inspect}, expected #{type}"
      end
    when ->(k) {key.to_s.include?(':')}
      begin
        normalize_jsonld(key, value)
      rescue Error => e
        errors << "#{type} has invalid content '#{key}': #{e.message}"
      end
    else
      errors << "#{type} has invalid property '#{key}': unsupported property"
    end
  end

  raise Error, errors.join("\n") unless errors.empty?
  self
end