Class: JSON::LD::Resource

Inherits:
Object
  • Object
show all
Includes:
RDF::Enumerable
Defined in:
lib/json/ld/resource.rb

Overview

Simple Ruby reflector class to provide native access to JSON-LD objects

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(node_definition, options = {}) ⇒ Resource

A new resource from the parsed graph

Parameters:

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

Options Hash (options):

  • :context (String) —

    Resource context, used for finding appropriate collection and JSON-LD context.

  • :clean (Boolean) — default: false
  • :compact (Boolean) — default: false —

    Assume ‘node_definition` is in expanded form and compact using `context`.

  • :reconciled (Boolean) — default: !new —

    node_definition is not based on Mongo IDs and must be reconciled against Mongo, or merged into another resource.

  • :new (Boolean) — default: true —

    This is a new resource, not yet saved to Mongo

  • :stub (Boolean) — default: false —

    This is a stand-in for another resource that has not yet been retrieved (or created) from Mongo



79
80
81
82
83
84
85
86
87
88
89
90
91
92
 
# File 'lib/json/ld/resource.rb', line 79

def initialize(node_definition, options = {})
  @context = options[:context]
  @clean = options.fetch(:clean, false)
  @new = options.fetch(:new, true)
  @reconciled = options.fetch(:reconciled, !@new)
  @resolved = false
  @attributes = if options[:compact]
    JSON::LD::API.compact(node_definition, @context)
  else
    node_definition
  end
  @id = @attributes['@id']
  @anon = @id.nil? || @id.to_s[0,2] == '_:'
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method, *args) ⇒ Object

Access individual fields, from subject definition



218
219
220
 
# File 'lib/json/ld/resource.rb', line 218

def method_missing(method, *args)
  property(method.to_s)
end

Instance Attribute Details

#attributes ⇒ Hash<String => Object] Object representation of resource (readonly)

Returns Hash<String => Object] Object representation of resource.

Returns:

  • (Hash<String => Object] Object representation of resource) —

    Hash<String => Object] Object representation of resource



10
11
12
 
# File 'lib/json/ld/resource.rb', line 10

def attributes
  @attributes
end

#context ⇒ JSON::LD::Context (readonly)

Returns Context associated with this resource.

Returns:



16
17
18
 
# File 'lib/json/ld/resource.rb', line 16

def context
  @context
end

#id ⇒ String (readonly)

Returns ID of this resource.

Returns:

  • (String) —

    ID of this resource



13
14
15
 
# File 'lib/json/ld/resource.rb', line 13

def id
  @id
end

Instance Method Details

#anonymous? ⇒ Boolean

Anonymous resources have BNode ids or no schema:url

Returns:

  • (Boolean) 


47
 
# File 'lib/json/ld/resource.rb', line 47

def anonymous?; @anon; end

#clean? ⇒ Boolean

Is this resource clean (i.e., saved to mongo?)

Returns:

  • (Boolean) 


22
 
# File 'lib/json/ld/resource.rb', line 22

def clean?; @clean; end

#deresolve ⇒ Hash

Reverse resolution of resource attributes. Just returns ‘attributes` if resource is unresolved. Otherwise, replaces `Resource` values with node references.

Result is expanded and re-compacted to get to normalized representation.

Returns:

  • (Hash) —

    deresolved attribute hash



111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
 
# File 'lib/json/ld/resource.rb', line 111

def deresolve
  node_definition = if resolved?
    deresolved = attributes.keys.inject({}) do |memo, prop|
      value = attributes[prop]
      memo[prop] = case value
      when Resource
        {'id' => value.id}
      when Array
        value.map do |v|
          v.is_a?(Resource) ? {'id' => v.id} : v
        end
      else
        value
      end
      memo
    end
    deresolved
  else
    attributes
  end

  compacted = nil
  JSON::LD::API.expand(node_definition, expandContext: @context) do |expanded|
    compacted = JSON::LD::API.compact(expanded, @context)
  end
  compacted.delete_if {|k, v| k == '@context'}
end

#dirty? ⇒ Boolean

Is this resource dirty (i.e., not yet saved to mongo?)

Returns:

  • (Boolean) 


28
 
# File 'lib/json/ld/resource.rb', line 28

def dirty?; !clean?; end

#each(&block) ⇒ Object

Enumerate over statements associated with this resource



151
152
153
 
# File 'lib/json/ld/resource.rb', line 151

def each(&block)
  JSON::LD::API.toRdf(attributes, expandContext: context, &block)
end

#hash ⇒ Integer

Return a hash of this object, suitable for use by for ETag

Returns:

  • (Integer) 


97
98
99
 
# File 'lib/json/ld/resource.rb', line 97

def hash
  self.deresolve.hash
end

#inspect ⇒ Object 



222
223
224
225
226
227
228
 
# File 'lib/json/ld/resource.rb', line 222

def inspect
  "<Resource" +
  attributes.map do |k, v|
    "\n  #{k}: #{v.inspect}"
  end.join(" ") +
  ">"
end

#new? ⇒ Boolean

Is this a new resource, which has not yet been synched or created within the DB?

Returns:

  • (Boolean) 


57
 
# File 'lib/json/ld/resource.rb', line 57

def new?; !!@new; end

#property(prop_name) ⇒ Object

Access individual fields, from subject definition



214
 
# File 'lib/json/ld/resource.rb', line 214

def property(prop_name); @attributes.fetch(prop_name, nil); end

#reconciled? ⇒ Boolean

Has this resource been reconciled against a mongo ID?

Returns:

  • (Boolean) 


34
 
# File 'lib/json/ld/resource.rb', line 34

def reconciled?; @reconciled; end

#resolve(reference_map) ⇒ Resource

Update node references using the provided map. This replaces node references with Resources, either stub or instantiated.

Node references with ids not in the reference_map will cause stub resources to be added to the map.

Parameters:

  • reference_map (Hash{String => Resource})

Returns:



165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
 
# File 'lib/json/ld/resource.rb', line 165

def resolve(reference_map)
  return if resolved?
  def update_obj(obj, reference_map)
    case obj
    when Array
      obj.map {|o| update_obj(o, reference_map)}
    when Hash
      if node_reference?(obj)
        reference_map[obj['id']] ||= Resource.new(obj,
          context: @context_name,
          clean: false,
          stub: true
          )
      else
        obj.each_key do |k|
          obj[k] = update_obj(obj[k], reference_map)
        end
        obj
      end
    else
      obj
    end
  end

  #$logger.debug "resolve(0): #{attributes.inspect}"
  @attributes.each do |k, v|
    next if %w(id type).include?(k)
    @attributes[k] = update_obj(@attributes[k], reference_map)
  end
  #$logger.debug "resolve(1): #{attributes.inspect}"
  @resolved = true
  self
end

#resolved? ⇒ Boolean

Has this resource been resolved so that all references are to other Resources?

Returns:

  • (Boolean) 


41
 
# File 'lib/json/ld/resource.rb', line 41

def resolved?; @resolved; end

#save ⇒ Boolean

Override this method to implement save using an appropriate storage mechanism.

Save the object to the Mongo collection use Upsert to create things that don’t exist. First makes sure that the resource is valid.

Returns:

  • (Boolean) —

    true or false if resource not saved

Raises:

  • (NotImplementedError) 


208
209
210
 
# File 'lib/json/ld/resource.rb', line 208

def save
  raise NotImplementedError
end

#stub? ⇒ Boolean

Is this a stub resource, which has not yet been synched or created within the DB?

Returns:

  • (Boolean) 


52
 
# File 'lib/json/ld/resource.rb', line 52

def stub?; !!@stub; end

#to_json(options = nil) ⇒ String

Serialize to JSON-LD, minus ‘@context` using a deresolved version of the attributes

Parameters:

  • options (Hash) (defaults to: nil)

Returns:

  • (String) —

    serizlied JSON representation of resource



145
146
147
 
# File 'lib/json/ld/resource.rb', line 145

def to_json(options = nil)
  deresolve.to_json(options)
end

#update_obj(obj, reference_map) ⇒ Object 



167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
 
# File 'lib/json/ld/resource.rb', line 167

def update_obj(obj, reference_map)
  case obj
  when Array
    obj.map {|o| update_obj(o, reference_map)}
  when Hash
    if node_reference?(obj)
      reference_map[obj['id']] ||= Resource.new(obj,
        context: @context_name,
        clean: false,
        stub: true
        )
    else
      obj.each_key do |k|
        obj[k] = update_obj(obj[k], reference_map)
      end
      obj
    end
  else
    obj
  end
end