# -*- encoding: utf-8 -*-
# frozen_string_literal: true
require 'openssl'
require 'cgi'
require 'json/ld/expand'
require 'json/ld/compact'
require 'json/ld/flatten'
require 'json/ld/frame'
require 'json/ld/to_rdf'
require 'json/ld/from_rdf'
begin
require 'jsonlint'
rescue LoadError
end
module JSON::LD
##
# A JSON-LD processor based on the JsonLdProcessor interface.
#
# This API provides a clean mechanism that enables developers to convert JSON-LD data into a a variety of output formats that are easier to work with in various programming languages. If a JSON-LD API is provided in a programming environment, the entirety of the following API must be implemented.
#
# Note that the API method signatures are somewhat different than what is specified, as the use of Futures and explicit callback parameters is not as relevant for Ruby-based interfaces.
#
# @see https://www.w3.org/TR/json-ld11-api/#the-application-programming-interface
# @author [Gregg Kellogg](http://greggkellogg.net/)
class API
include Expand
include Compact
include ToRDF
include Flatten
include FromRDF
include Frame
include RDF::Util::Logger
# Options used for open_file
OPEN_OPTS = {
headers: {"Accept" => "application/ld+json, text/html;q=0.8, application/xhtml+xml;q=0.8, application/json;q=0.5"}
}
# The following constants are used to reduce object allocations
LINK_REL_CONTEXT = %w(rel http://www.w3.org/ns/json-ld#context).freeze
LINK_REL_ALTERNATE = %w(rel alternate).freeze
LINK_TYPE_JSONLD = %w(type application/ld+json).freeze
JSON_LD_PROCESSING_MODES = %w(json-ld-1.0 json-ld-1.1).freeze
# Current input
# @!attribute [rw] input
# @return [String, #read, Hash, Array]
attr_accessor :value
# Input evaluation context
# @!attribute [rw] context
# @return [JSON::LD::Context]
attr_accessor :context
# Current Blank Node Namer
# @!attribute [r] namer
# @return [JSON::LD::BlankNodeNamer]
attr_reader :namer
##
# Initialize the API, reading in any document and setting global options
#
# @param [String, #read, Hash, Array] input
# @param [String, #read, Hash, Array, JSON::LD::Context] context
# An external context to use additionally to the context embedded in input when expanding the input.
# @param [Hash{Symbol => Object}] options
# @option options [Symbol] :adapter used with MultiJson
# @option options [RDF::URI, String, #to_s] :base
# The Base IRI to use when expanding the document. This overrides the value of `input` if it is a _IRI_. If not specified and `input` is not an _IRI_, the base IRI defaults to the current document IRI if in a browser context, or the empty string if there is no document context. If not specified, and a base IRI is found from `input`, options[:base] will be modified with this value.
# @option options [Boolean] :compactArrays (true)
# If set to `true`, the JSON-LD processor replaces arrays with just one element with that element during compaction. If set to `false`, all arrays will remain arrays even if they have just one element.
# @option options [Boolean] :compactToRelative (true)
# Creates document relative IRIs when compacting, if `true`, otherwise leaves expanded.
# @option options [Proc] :documentLoader
# The callback of the loader to be used to retrieve remote documents and contexts. If specified, it must be used to retrieve remote documents and contexts; otherwise, if not specified, the processor's built-in loader must be used. See {documentLoader} for the method signature.
# @option options [String, #read, Hash, Array, JSON::LD::Context] :expandContext
# A context that is used to initialize the active context when expanding a document.
# @option options [Boolean] :extendedRepresentation (false)
# Use the extended internal representation.
# @option options [Boolean] :extractAllScripts
# If set, when given an HTML input without a fragment identifier, extracts all `script` elements with type `application/ld+json` into an array during expansion.
# @option options [Boolean, String, RDF::URI] :flatten
# If set to a value that is not `false`, the JSON-LD processor must modify the output of the Compaction Algorithm or the Expansion Algorithm by coalescing all properties associated with each subject via the Flattening Algorithm. The value of `flatten must` be either an _IRI_ value representing the name of the graph to flatten, or `true`. If the value is `true`, then the first graph encountered in the input document is selected and flattened.
# @option options [String] :language
# When set, this has the effect of inserting a context definition with `@language` set to the associated value, creating a default language for interpreting string values.
# @option options [Symbol] :library
# One of :nokogiri or :rexml. If nil/unspecified uses :nokogiri if available, :rexml otherwise.
# @option options [Boolean] :lowercaseLanguage
# By default, language tags are left as is. To normalize to lowercase, set this option to `true`.
# @option options [Boolean] :ordered (true)
# Order traversal of dictionary members by key when performing algorithms.
# @option options [String] :processingMode
# Processing mode, json-ld-1.0 or json-ld-1.1.
# @option options [Boolean] :rdfstar (false)
# support parsing JSON-LD-star statement resources.
# @option options [Boolean] :rename_bnodes (true)
# Rename bnodes as part of expansion, or keep them the same.
# @option options [Boolean] :unique_bnodes (false)
# Use unique bnode identifiers, defaults to using the identifier which the node was originally initialized with (if any).
# @option options [Boolean] :validate Validate input, if a string or readable object.
# @yield [api]
# @yieldparam [API]
# @raise [JsonLdError]
def initialize(input, context, **options, &block)
@options = {
compactArrays: true,
ordered: false,
extractAllScripts: false,
rename_bnodes: true,
unique_bnodes: false,
}.merge(options)
@namer = @options[:unique_bnodes] ? BlankNodeUniqer.new : (@options[:rename_bnodes] ? BlankNodeNamer.new("b") : BlankNodeMapper.new)
@options[:base] = RDF::URI(@options[:base]) if @options[:base] && !@options[:base].is_a?(RDF::URI)
# For context via Link header
_, context_ref = nil, nil
@value = case input
when Array, Hash then input.dup
when IO, StringIO, String
remote_doc = self.class.loadRemoteDocument(input, **@options)
context_ref = remote_doc.contextUrl
@options[:base] = RDF::URI(remote_doc.documentUrl) if remote_doc.documentUrl && !@options[:no_default_base]
case remote_doc.document
when String
mj_opts = options.keep_if {|k,v| k != :adapter || MUTLI_JSON_ADAPTERS.include?(v)}
MultiJson.load(remote_doc.document, **mj_opts)
else
# Already parsed
remote_doc.document
end
end
# If not provided, first use context from document, or from a Link header
context ||= context_ref || {}
@context = Context.parse(context, **@options)
if block_given?
case block.arity
when 0, -1 then instance_eval(&block)
else block.call(self)
end
end
end
# This is used internally only
private :initialize
##
# Expands the given input according to the steps in the Expansion Algorithm. The input must be copied, expanded and returned if there are no errors. If the expansion fails, an appropriate exception must be thrown.
#
# The resulting `Array` either returned or yielded
#
# @param [String, #read, Hash, Array] input
# The JSON-LD object to copy and perform the expansion upon.
# @param [Proc] serializer (nil)
# A Serializer method used for generating the JSON serialization of the result. If absent, the internal Ruby objects are returned, which can be transformed to JSON externally via `#to_json`.
# See {JSON::LD::API.serializer}.
# @param [Hash{Symbol => Object}] options
# @option options (see #initialize)
# @raise [JsonLdError]
# @yield jsonld, base_iri
# @yieldparam [Array<Hash>] jsonld
# The expanded JSON-LD document
# @yieldparam [RDF::URI] base_iri
# The document base as determined during expansion
# @yieldreturn [Object] returned object
# @return [Object, Array<Hash>]
# If a block is given, the result of evaluating the block is returned, otherwise, the expanded JSON-LD document
# @see https://www.w3.org/TR/json-ld11-api/#expansion-algorithm
def self.expand(input, framing: false, serializer: nil, **options, &block)
result = doc_base = nil
API.new(input, options[:expandContext], **options) do
result = self.expand(self.value, nil, self.context,
framing: framing)
doc_base = @options[:base]
end
# If, after the algorithm outlined above is run, the resulting element is an JSON object with just a @graph property, element is set to the value of @graph's value.
result = result['@graph'] if result.is_a?(Hash) && result.length == 1 && result.key?('@graph')
# Finally, if element is a JSON object, it is wrapped into an array.
result = [result].compact unless result.is_a?(Array)
result = serializer.call(result, **options) if serializer
if block_given?
case block.arity
when 1 then yield(result)
when 2 then yield(result, doc_base)
else
raise "Unexpected number of yield parameters to expand"
end
else
result
end
end
##
# Compacts the given input according to the steps in the Compaction Algorithm. The input must be copied, compacted and returned if there are no errors. If the compaction fails, an appropirate exception must be thrown.
#
# If no context is provided, the input document is compacted using the top-level context of the document
#
# The resulting `Hash` is either returned or yielded, if a block is given.
#
# @param [String, #read, Hash, Array] input
# The JSON-LD object to copy and perform the compaction upon.
# @param [String, #read, Hash, Array, JSON::LD::Context] context
# The base context to use when compacting the input.
# @param [Proc] serializer (nil)
# A Serializer instance used for generating the JSON serialization of the result. If absent, the internal Ruby objects are returned, which can be transformed to JSON externally via `#to_json`.
# See {JSON::LD::API.serializer}.
# @param [Boolean] expanded (false) Input is already expanded
# @param [Hash{Symbol => Object}] options
# @option options (see #initialize)
# @yield jsonld
# @yieldparam [Hash] jsonld
# The compacted JSON-LD document
# @yieldreturn [Object] returned object
# @return [Object, Hash]
# If a block is given, the result of evaluating the block is returned, otherwise, the compacted JSON-LD document
# @raise [JsonLdError]
# @see https://www.w3.org/TR/json-ld11-api/#compaction-algorithm
def self.compact(input, context, expanded: false, serializer: nil, **options)
result = nil
options = {compactToRelative: true}.merge(options)
# 1) Perform the Expansion Algorithm on the JSON-LD input.
# This removes any existing context to allow the given context to be cleanly applied.
expanded_input = expanded ? input : API.expand(input, ordered: false, **options) do |res, base_iri|
options[:base] ||= RDF::URI(base_iri) if base_iri && options[:compactToRelative]
res
end
API.new(expanded_input, context, no_default_base: true, **options) do
# log_debug(".compact") {"expanded input: #{expanded_input.to_json(JSON_STATE) rescue 'malformed json'}"}
result = compact(value)
# xxx) Add the given context to the output
ctx = self.context.serialize(provided_context: context)
if result.is_a?(Array)
kwgraph = self.context.compact_iri('@graph', vocab: true)
result = result.empty? ? {} : {kwgraph => result}
end
result = ctx.merge(result) unless ctx.fetch('@context', {}).empty?
end
result = serializer.call(result, **options) if serializer
block_given? ? yield(result) : result
end
##
# This algorithm flattens an expanded JSON-LD document by collecting all properties of a node in a single JSON object and labeling all blank nodes with blank node identifiers. This resulting uniform shape of the document, may drastically simplify the code required to process JSON-LD data in certain applications.
#
# The resulting `Array` is either returned, or yielded if a block is given.
#
# @param [String, #read, Hash, Array] input
# The JSON-LD object or array of JSON-LD objects to flatten or an IRI referencing the JSON-LD document to flatten.
# @param [String, #read, Hash, Array, JSON::LD::EvaluationContext] context
# An optional external context to use additionally to the context embedded in input when expanding the input.
# @param [Boolean] expanded (false) Input is already expanded
# @param [Proc] serializer (nil)
# A Serializer instance used for generating the JSON serialization of the result. If absent, the internal Ruby objects are returned, which can be transformed to JSON externally via `#to_json`.
# See {JSON::LD::API.serializer}.
# @param [Hash{Symbol => Object}] options
# @option options (see #initialize)
# @option options [Boolean] :createAnnotations
# Unfold embedded nodes which can be represented using `@annotation`.
# @yield jsonld
# @yieldparam [Hash] jsonld
# The flattened JSON-LD document
# @yieldreturn [Object] returned object
# @return [Object, Hash]
# If a block is given, the result of evaluating the block is returned, otherwise, the flattened JSON-LD document
# @see https://www.w3.org/TR/json-ld11-api/#framing-algorithm
def self.flatten(input, context, expanded: false, serializer: nil, **options)
flattened = []
options = {
compactToRelative: true,
extractAllScripts: true,
}.merge(options)
# Expand input to simplify processing
expanded_input = expanded ? input : API.expand(input, **options) do |result, base_iri|
options[:base] ||= RDF::URI(base_iri) if base_iri && options[:compactToRelative]
result
end
# Initialize input using
API.new(expanded_input, context, no_default_base: true, **options) do
# log_debug(".flatten") {"expanded input: #{value.to_json(JSON_STATE) rescue 'malformed json'}"}
# Rename blank nodes recusively. Note that this does not create new blank node identifiers where none exist, which is performed in the node map generation algorithm.
@value = rename_bnodes(@value) if @options[:rename_bnodes]
# Initialize node map to a JSON object consisting of a single member whose key is @default and whose value is an empty JSON object.
graph_maps = {'@default' => {}}
create_node_map(value, graph_maps)
# If create annotations flag is set, then update each node map in graph maps with the result of calling the create annotations algorithm.
if options[:createAnnotations]
graph_maps.values.each do |node_map|
create_annotations(node_map)
end
end
default_graph = graph_maps['@default']
graph_maps.keys.opt_sort(ordered: @options[:ordered]).each do |graph_name|
next if graph_name == '@default'
graph = graph_maps[graph_name]
entry = default_graph[graph_name] ||= {'@id' => graph_name}
nodes = entry['@graph'] ||= []
graph.keys.opt_sort(ordered: @options[:ordered]).each do |id|
nodes << graph[id] unless node_reference?(graph[id])
end
end
default_graph.keys.opt_sort(ordered: @options[:ordered]).each do |id|
flattened << default_graph[id] unless node_reference?(default_graph[id])
end
if context && !flattened.empty?
# Otherwise, return the result of compacting flattened according the Compaction algorithm passing context ensuring that the compaction result uses the @graph keyword (or its alias) at the top-level, even if the context is empty or if there is only one element to put in the @graph array. This ensures that the returned document has a deterministic structure.
compacted = as_array(compact(flattened))
kwgraph = self.context.compact_iri('@graph', vocab: true)
flattened = self.context.
serialize(provided_context: context).
merge(kwgraph => compacted)
end
end
flattened = serializer.call(flattened, **options) if serializer
block_given? ? yield(flattened) : flattened
end
##
# Frames the given input using the frame according to the steps in the Framing Algorithm. The input is used to build the framed output and is returned if there are no errors. If there are no matches for the frame, null must be returned. Exceptions must be thrown if there are errors.
#
# The resulting `Array` is either returned, or yielded if a block is given.
#
# @param [String, #read, Hash, Array] input
# The JSON-LD object to copy and perform the framing on.
# @param [String, #read, Hash, Array] frame
# The frame to use when re-arranging the data.
# @param [Boolean] expanded (false) Input is already expanded
# @option options (see #initialize)
# @option options ['@always', '@link', '@once', '@never'] :embed ('@once')
# a flag specifying that objects should be directly embedded in the output, instead of being referred to by their IRI.
# @option options [Boolean] :explicit (false)
# a flag specifying that for properties to be included in the output, they must be explicitly declared in the framing context.
# @option options [Boolean] :requireAll (false)
# A flag specifying that all properties present in the input frame must either have a default value or be present in the JSON-LD input for the frame to match.
# @option options [Boolean] :omitDefault (false)
# a flag specifying that properties that are missing from the JSON-LD input should be omitted from the output.
# @option options [Boolean] :pruneBlankNodeIdentifiers (true) removes blank node identifiers that are only used once.
# @option options [Boolean] :omitGraph does not use `@graph` at top level unless necessary to describe multiple objects, defaults to `true` if processingMode is 1.1, otherwise `false`.
# @yield jsonld
# @yieldparam [Hash] jsonld
# The framed JSON-LD document
# @yieldreturn [Object] returned object
# @return [Object, Hash]
# If a block is given, the result of evaluating the block is returned, otherwise, the framed JSON-LD document
# @raise [InvalidFrame]
# @see https://www.w3.org/TR/json-ld11-api/#framing-algorithm
def self.frame(input, frame, expanded: false, serializer: nil, **options)
result = nil
options = {
base: (RDF::URI(input) if input.is_a?(String)),
compactArrays: true,
compactToRelative: true,
embed: '@once',
explicit: false,
requireAll: false,
omitDefault: false,
}.merge(options)
framing_state = {
graphMap: {},
graphStack: [],
subjectStack: [],
link: {},
embedded: false # False at the top-level
}
# de-reference frame to create the framing object
frame = case frame
when Hash then frame.dup
when IO, StringIO, String
remote_doc = loadRemoteDocument(frame,
profile: 'http://www.w3.org/ns/json-ld#frame',
requestProfile: 'http://www.w3.org/ns/json-ld#frame',
**options)
if remote_doc.document.is_a?(String)
mj_opts = options.keep_if {|k,v| k != :adapter || MUTLI_JSON_ADAPTERS.include?(v)}
MultiJson.load(remote_doc.document, **mj_opts)
else
remote_doc.document
end
end
# Expand input to simplify processing
expanded_input = expanded ? input : API.expand(input, ordered: false, **options) do |res, base_iri|
options[:base] ||= RDF::URI(base_iri) if base_iri && options[:compactToRelative]
res
end
# Expand frame to simplify processing
expanded_frame = API.expand(frame, framing: true, ordered: false, **options)
# Initialize input using frame as context
API.new(expanded_input, frame['@context'], no_default_base: true, **options) do
# log_debug(".frame") {"expanded input: #{expanded_input.to_json(JSON_STATE) rescue 'malformed json'}"}
# log_debug(".frame") {"expanded frame: #{expanded_frame.to_json(JSON_STATE) rescue 'malformed json'}"}
if %w(@first @last).include?(options[:embed]) && context.processingMode('json-ld-1.1')
raise JSON::LD::JsonLdError::InvalidEmbedValue, "#{options[:embed]} is not a valid value of @embed in 1.1 mode" if @options[:validate]
warn "[DEPRECATION] #{options[:embed]} is not a valid value of @embed in 1.1 mode.\n"
end
# Set omitGraph option, if not present, based on processingMode
unless options.key?(:omitGraph)
options[:omitGraph] = context.processingMode('json-ld-1.1')
end
# Rename blank nodes recusively. Note that this does not create new blank node identifiers where none exist, which is performed in the node map generation algorithm.
@value = rename_bnodes(@value)
# Get framing nodes from expanded input, replacing Blank Node identifiers as necessary
create_node_map(value, framing_state[:graphMap], active_graph: '@default')
frame_keys = frame.keys.map {|k| context.expand_iri(k, vocab: true)}
if frame_keys.include?('@graph')
# If frame contains @graph, it matches the default graph.
framing_state[:graph] = '@default'
else
# If frame does not contain @graph used the merged graph.
framing_state[:graph] = '@merged'
framing_state[:link]['@merged'] = {}
framing_state[:graphMap]['@merged'] = merge_node_map_graphs(framing_state[:graphMap])
end
framing_state[:subjects] = framing_state[:graphMap][framing_state[:graph]]
result = []
frame(framing_state, framing_state[:subjects].keys.opt_sort(ordered: @options[:ordered]), (expanded_frame.first || {}), parent: result, **options)
# Default to based on processinMode
if !options.key?(:pruneBlankNodeIdentifiers)
options[:pruneBlankNodeIdentifiers] = context.processingMode('json-ld-1.1')
end
# Count blank node identifiers used in the document, if pruning
if options[:pruneBlankNodeIdentifiers]
bnodes_to_clear = count_blank_node_identifiers(result).collect {|k, v| k if v == 1}.compact
result = prune_bnodes(result, bnodes_to_clear)
end
# Replace values with `@preserve` with the content of its entry.
result = cleanup_preserve(result)
# log_debug(".frame") {"expanded result: #{result.to_json(JSON_STATE) rescue 'malformed json'}"}
# Compact result
compacted = compact(result)
# @replace `@null` with nil, compacting arrays
compacted = cleanup_null(compacted)
compacted = [compacted] unless options[:omitGraph] || compacted.is_a?(Array)
# Add the given context to the output
result = if !compacted.is_a?(Array)
compacted
else
kwgraph = context.compact_iri('@graph', vocab: true)
{kwgraph => compacted}
end
# Only add context if one was provided
result = context.serialize(provided_context: frame).merge(result) if frame['@context']
# log_debug(".frame") {"after compact: #{result.to_json(JSON_STATE) rescue 'malformed json'}"}
result
end
result = serializer.call(result, **options) if serializer
block_given? ? yield(result) : result
end
##
# Processes the input according to the RDF Conversion Algorithm, calling the provided callback for each triple generated.
#
# @param [String, #read, Hash, Array] input
# The JSON-LD object to process when outputting statements.
# @param [Boolean] expanded (false) Input is already expanded
# @option options (see #initialize)
# @option options [Boolean] :produceGeneralizedRdf (false)
# If true, output will include statements having blank node predicates, otherwise they are dropped.
# @raise [JsonLdError]
# @yield statement
# @yieldparam [RDF::Statement] statement
# @return [RDF::Enumerable] set of statements, unless a block is given.
def self.toRdf(input, expanded: false, **options, &block)
unless block_given?
results = []
results.extend(RDF::Enumerable)
self.toRdf(input, expanded: expanded, **options) do |stmt|
results << stmt
end
return results
end
options = {
extractAllScripts: true,
}.merge(options)
# Flatten input to simplify processing
flattened_input = API.flatten(input, nil, expanded: expanded, ordered: false, **options)
API.new(flattened_input, nil, **options) do
# 1) Perform the Expansion Algorithm on the JSON-LD input.
# This removes any existing context to allow the given context to be cleanly applied.
# log_debug(".toRdf") {"flattened input: #{flattened_input.to_json(JSON_STATE) rescue 'malformed json'}"}
# Recurse through input
flattened_input.each do |node|
item_to_rdf(node) do |statement|
next if statement.predicate.node? && !options[:produceGeneralizedRdf]
# Drop invalid statements (other than IRIs)
unless statement.valid_extended?
# log_debug(".toRdf") {"drop invalid statement: #{statement.to_nquads}"}
next
end
yield statement
end
end
end
end
##
# Take an ordered list of RDF::Statements and turn them into a JSON-LD document.
#
# The resulting `Array` is either returned or yielded, if a block is given.
#
# @param [RDF::Enumerable] input
# @param [Boolean] useRdfType (false)
# If set to `true`, the JSON-LD processor will treat `rdf:type` like a normal property instead of using `@type`.
# @param [Boolean] useNativeTypes (false) use native representations
# @param [Proc] serializer (nil)
# A Serializer instance used for generating the JSON serialization of the result. If absent, the internal Ruby objects are returned, which can be transformed to JSON externally via `#to_json`.
# See {JSON::LD::API.serializer}.
# @param [Hash{Symbol => Object}] options
# @option options (see #initialize)
# @yield jsonld
# @yieldparam [Hash] jsonld
# The JSON-LD document in expanded form
# @yieldreturn [Object] returned object
# @return [Object, Hash]
# If a block is given, the result of evaluating the block is returned, otherwise, the expanded JSON-LD document
def self.fromRdf(input, useRdfType: false, useNativeTypes: false, serializer: nil, **options, &block)
result = nil
API.new(nil, nil, **options) do
result = from_statements(input,
extendedRepresentation: options[:extendedRepresentation],
useRdfType: useRdfType,
useNativeTypes: useNativeTypes)
end
result = serializer.call(result, **options) if serializer
block_given? ? yield(result) : result
end
##
# Uses built-in or provided documentLoader to retrieve a parsed document.
#
# @param [RDF::URI, String] url
# @param [Regexp] allowed_content_types
# A regular expression matching other content types allowed
# beyond types for JSON and HTML.
# @param [String, RDF::URI] base
# Location to use as documentUrl instead of `url`.
# @option options [Proc] :documentLoader
# The callback of the loader to be used to retrieve remote documents and contexts.
# @param [Boolean] extractAllScripts
# If set to `true`, when extracting JSON-LD script elements from HTML, unless a specific fragment identifier is targeted, extracts all encountered JSON-LD script elements using an array form, if necessary.
# @param [String] profile
# When the resulting `contentType` is `text/html` or `application/xhtml+xml`, this option determines the profile to use for selecting a JSON-LD script elements.
# @param [String] requestProfile
# One or more IRIs to use in the request as a profile parameter.
# @param [Boolean] validate (false)
# Allow only appropriate content types
# @param [Hash<Symbol => Object>] options
# @yield remote_document
# @yieldparam [RemoteDocumentRemoteDocument, RDF::Util::File::RemoteDocument] remote_document
# @yieldreturn [Object] returned object
# @return [Object, RemoteDocument]
# If a block is given, the result of evaluating the block is returned, otherwise, the retrieved remote document and context information unless block given
# @raise [JsonLdError]
def self.loadRemoteDocument(url,
allowed_content_types: nil,
base: nil,
documentLoader: nil,
extractAllScripts: false,
profile: nil,
requestProfile: nil,
validate: false,
**options)
documentLoader ||= self.method(:documentLoader)
options = OPEN_OPTS.merge(options)
if requestProfile
# Add any request profile
options[:headers]['Accept'] = options[:headers]['Accept'].sub('application/ld+json,', "application/ld+json;profile=#{requestProfile}, application/ld+json;q=0.9,")
end
documentLoader.call(url, **options) do |remote_doc|
case remote_doc
when RDF::Util::File::RemoteDocument
# Convert to RemoteDocument
context_url = if remote_doc.content_type != 'application/ld+json' &&
(remote_doc.content_type == 'application/json' ||
remote_doc.content_type.to_s.match?(%r(application/\w+\+json)))
# Get context link(s)
# Note, we can't simply use #find_link, as we need to detect multiple
links = remote_doc.links.links.select do |link|
link.attr_pairs.include?(LINK_REL_CONTEXT)
end
raise JSON::LD::JsonLdError::MultipleContextLinkHeaders,
"expected at most 1 Link header with rel=jsonld:context, got #{links.length}" if links.length > 1
Array(links.first).first
end
# If content-type is not application/ld+json, nor any other +json and a link with rel=alternate and type='application/ld+json' is found, use that instead
alternate = !remote_doc.content_type.match?(%r(application/(\w*\+)?json)) && remote_doc.links.links.detect do |link|
link.attr_pairs.include?(LINK_REL_ALTERNATE) &&
link.attr_pairs.include?(LINK_TYPE_JSONLD)
end
remote_doc = if alternate
# Load alternate relative to URL
loadRemoteDocument(RDF::URI(url).join(alternate.href),
extractAllScripts: extractAllScripts,
profile: profile,
requestProfile: requestProfile,
validate: validate,
base: base,
**options)
else
RemoteDocument.new(remote_doc.read,
documentUrl: remote_doc.base_uri,
contentType: remote_doc.content_type,
contextUrl: context_url)
end
when RemoteDocument
# Pass through
else
raise JSON::LD::JsonLdError::LoadingDocumentFailed, "unknown result from documentLoader: #{remote_doc.class}"
end
# Use specified document location
remote_doc.documentUrl = base if base
# Parse any HTML
if remote_doc.document.is_a?(String)
remote_doc.document = case remote_doc.contentType
when 'text/html', 'application/xhtml+xml'
load_html(remote_doc.document,
url: remote_doc.documentUrl,
extractAllScripts: extractAllScripts,
profile: profile,
**options) do |base|
remote_doc.documentUrl = base
end
else
validate_input(remote_doc.document, url: remote_doc.documentUrl) if validate
mj_opts = options.keep_if {|k,v| k != :adapter || MUTLI_JSON_ADAPTERS.include?(v)}
MultiJson.load(remote_doc.document, **mj_opts)
end
end
if remote_doc.contentType && validate
raise IOError, "url: #{url}, contentType: #{remote_doc.contentType}" unless
remote_doc.contentType.match?(/application\/(.+\+)?json|text\/html|application\/xhtml\+xml/) ||
(allowed_content_types && remote_doc.contentType.match?(allowed_content_types))
end
block_given? ? yield(remote_doc) : remote_doc
end
rescue IOError, MultiJson::ParseError => e
raise JSON::LD::JsonLdError::LoadingDocumentFailed, e.message
end
##
# Default document loader.
# @param [RDF::URI, String] url
# @param [Boolean] extractAllScripts
# If set to `true`, when extracting JSON-LD script elements from HTML, unless a specific fragment identifier is targeted, extracts all encountered JSON-LD script elements using an array form, if necessary.
# @param [String] profile
# When the resulting `contentType` is `text/html` or `application/xhtml+xml`, this option determines the profile to use for selecting a JSON-LD script elements.
# @param [String] requestProfile
# One or more IRIs to use in the request as a profile parameter.
# @param [Hash<Symbol => Object>] options
# @yield remote_document
# @yieldparam [RemoteDocument, RDF::Util::File::RemoteDocument] remote_document
# @raise [IOError]
def self.documentLoader(url, extractAllScripts: false, profile: nil, requestProfile: nil, **options, &block)
case url
when IO, StringIO
base_uri = options[:base]
base_uri ||= url.base_uri if url.respond_to?(:base_uri)
content_type = options[:content_type]
content_type ||= url.content_type if url.respond_to?(:content_type)
context_url = if url.respond_to?(:links) && url.links &&
(content_type == 'application/json' || content_type.match?(%r(application/(^ld)+json)))
link = url.links.find_link(LINK_REL_CONTEXT)
link.href if link
end
block.call(RemoteDocument.new(url.read,
documentUrl: base_uri,
contentType: content_type,
contextUrl: context_url))
else
RDF::Util::File.open_file(url, **options, &block)
end
end
# Add class method aliases for backwards compatibility
class << self
alias :toRDF :toRdf
alias :fromRDF :fromRdf
end
##
# Load one or more script tags from an HTML source.
# Unescapes and uncomments input, returns the internal representation
# Yields document base
# @param [String] input
# @param [String] url Original URL
# @param [:nokogiri, :rexml] library (nil)
# @param [Boolean] extractAllScripts (false)
# @param [Boolean] profile (nil) Optional priortized profile when loading a single script by type.
# @param [Hash{Symbol => Object}] options
def self.load_html(input, url:,
library: nil,
extractAllScripts: false,
profile: nil,
**options)
if input.is_a?(String)
library ||= begin
require 'nokogiri'
:nokogiri
rescue LoadError
:rexml
end
require "json/ld/html/#{library}"
# Parse HTML using the appropriate library
implementation = case library
when :nokogiri then Nokogiri
when :rexml then REXML
end
self.extend(implementation)
input = begin
self.send("initialize_html_#{library}".to_sym, input, **options)
rescue
raise JSON::LD::JsonLdError::LoadingDocumentFailed, "Malformed HTML document: #{$!.message}"
end
# Potentially update options[:base]
if html_base = input.at_xpath("/html/head/base/@href")
base = RDF::URI(url) if url
html_base = RDF::URI(html_base)
html_base = base.join(html_base) if base
yield html_base
end
end
url = RDF::URI.parse(url)
if url.fragment
id = CGI.unescape(url.fragment)
# Find script with an ID based on that fragment.
element = input.at_xpath("//script[@id='#{id}']")
raise JSON::LD::JsonLdError::LoadingDocumentFailed, "No script tag found with id=#{id}" unless element
raise JSON::LD::JsonLdError::LoadingDocumentFailed, "Script tag has type=#{element.attributes['type']}" unless element.attributes['type'].to_s.start_with?('application/ld+json')
content = element.inner_html
validate_input(content, url: url) if options[:validate]
mj_opts = options.keep_if {|k,v| k != :adapter || MUTLI_JSON_ADAPTERS.include?(v)}
MultiJson.load(content, **mj_opts)
elsif extractAllScripts
res = []
elements = if profile
es = input.xpath("//script[starts-with(@type, 'application/ld+json;profile=#{profile}')]")
# If no profile script, just take a single script without profile
es = [input.at_xpath("//script[starts-with(@type, 'application/ld+json')]")].compact if es.empty?
es
else
input.xpath("//script[starts-with(@type, 'application/ld+json')]")
end
elements.each do |element|
content = element.inner_html
validate_input(content, url: url) if options[:validate]
mj_opts = options.keep_if {|k,v| k != :adapter || MUTLI_JSON_ADAPTERS.include?(v)}
r = MultiJson.load(content, **mj_opts)
if r.is_a?(Hash)
res << r
elsif r.is_a?(Array)
res = res.concat(r)
end
end
res
else
# Find the first script with type application/ld+json.
element = input.at_xpath("//script[starts-with(@type, 'application/ld+json;profile=#{profile}')]") if profile
element ||= input.at_xpath("//script[starts-with(@type, 'application/ld+json')]")
raise JSON::LD::JsonLdError::LoadingDocumentFailed, "No script tag found" unless element
content = element.inner_html
validate_input(content, url: url) if options[:validate]
mj_opts = options.keep_if {|k,v| k != :adapter || MUTLI_JSON_ADAPTERS.include?(v)}
MultiJson.load(content, **mj_opts)
end
rescue MultiJson::ParseError => e
raise JSON::LD::JsonLdError::InvalidScriptElement, e.message
end
##
# The default serializer for serialzing Ruby Objects to JSON.
#
# Defaults to `MultiJson.dump`
#
# @param [Object] object
# @param [Array<Object>] args
# other arguments that may be passed for some specific implementation.
# @param [Hash<Symbol, Object>] options
# options passed from the invoking context.
# @option options [Object] :serializer_opts (JSON_STATE)
def self.serializer(object, *args, **options)
serializer_opts = options.fetch(:serializer_opts, JSON_STATE)
MultiJson.dump(object, serializer_opts)
end
##
# Validate JSON using JsonLint, if loaded
private
def self.validate_input(input, url:)
return unless defined?(JsonLint)
jsonlint = JsonLint::Linter.new
input = StringIO.new(input) unless input.respond_to?(:read)
unless jsonlint.check_stream(input)
raise JsonLdError::LoadingDocumentFailed, "url: #{url}\n" + jsonlint.errors[''].join("\n")
end
input.rewind
end
##
# A {RemoteDocument} is returned from a {documentLoader}.
class RemoteDocument
# The final URL of the loaded document. This is important to handle HTTP redirects properly.
# @return [String]
attr_accessor :documentUrl
# The Content-Type of the loaded document, exclusive of any optional parameters.
# @return [String]
attr_reader :contentType
# @return [String]
# The URL of a remote context as specified by an HTTP Link header with rel=`http://www.w3.org/ns/json-ld#context`
attr_accessor :contextUrl
# The parsed retrieved document.
# @return [Array<Hash>, Hash]
attr_accessor :document
# The value of any profile parameter retrieved as part of the original contentType.
# @return [String]
attr_accessor :profile
# @param [RDF::Util::File::RemoteDocument] document
# @param [String] documentUrl
# The final URL of the loaded document. This is important to handle HTTP redirects properly.
# @param [String] contentType
# The Content-Type of the loaded document, exclusive of any optional parameters.
# @param [String] contextUrl
# The URL of a remote context as specified by an HTTP Link header with rel=`http://www.w3.org/ns/json-ld#context`
# @param [String] profile
# The value of any profile parameter retrieved as part of the original contentType.
# @option options [Hash{Symbol => Object}] options
def initialize(document, documentUrl: nil, contentType: nil, contextUrl: nil, profile: nil, **options)
@document = document
@documentUrl = documentUrl || options[:base_uri]
@contentType = contentType || options[:content_type]
@contextUrl = contextUrl
@profile = profile
end
end
end
end