Class: HalClient::Link

Inherits:
Object
  • Object
show all
Defined in:
lib/hal_client/link.rb

Overview

HAL representation of a single link. Provides access to an embedded representation.

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options) ⇒ Link

Create a new Link

options - name parameters

:rel - This Link's rel property
:target - An instance of Representation
:template - A URI template ( https://www.rfc-editor.org/rfc/rfc6570.txt )
:curie_resolver - An instance of CurieResolver (used to resolve curied rels)



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# File 'lib/hal_client/link.rb', line 15

def initialize(options)
  @literal_rel = options[:rel]
  @target = options[:target]
  @template = options[:template]
  @curie_resolver = options[:curie_resolver] || CurieResolver.new([])

  (fail ArgumentError, "A rel must be provided") if @literal_rel.nil?

  if @target.nil? && @template.nil?
    (fail ArgumentError, "A target or template must be provided")
  end

  if @target && @template
    (fail ArgumentError, "Cannot provide both a target and a template")
  end

  if @target && !@target.kind_of?(Representation)
    (fail ArgumentError, "Invalid HAL representation: #{target.inspect}")
  end

  if @template && !@template.kind_of?(Addressable::Template)
    (fail ArgumentError, "Invalid Addressable::Template: #{template.inspect}")
  end
end

Instance Attribute Details

#curie_resolver ⇒ Object

Returns the value of attribute curie_resolver.



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# File 'lib/hal_client/link.rb', line 40

def curie_resolver
  @curie_resolver
end

#literal_rel ⇒ Object

Returns the value of attribute literal_rel.



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# File 'lib/hal_client/link.rb', line 40

def literal_rel
  @literal_rel
end

#target ⇒ Object

Returns the value of attribute target.



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# File 'lib/hal_client/link.rb', line 40

def target
  @target
end

#template ⇒ Object

Returns the value of attribute template.



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# File 'lib/hal_client/link.rb', line 40

def template
  @template
end

Class Method Details

.new_from_embedded_entry(options) ⇒ Object

Create a new Link using an entry from the ‘_embedded’ section of a HAL document

options - name parameters

:hash_entry - a hash containing keys :rel (string) and :data (hash from a '_embedded' entry)
:hal_client - an instance of HalClient
:curie_resolver - An instance of CurieResolver (used to resolve curied rels)
:base_url - Base url for resolving relative links in hash_entry (probably the parent

document’s “self” link)



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# File 'lib/hal_client/link.rb', line 81

def self.new_from_embedded_entry(options)
  hash_entry = options[:hash_entry]
  hal_client = options[:hal_client]
  curie_resolver = options[:curie_resolver]
  base_url = options[:base_url]

  rel = hash_entry[:rel]
  hash_data = hash_entry[:data]

  explicit_url = self_href(hash_data)
  hash_data['_links']['self']['href'] = (base_url + explicit_url).to_s if explicit_url

  Link.new(rel: rel,
           target: Representation.new(hal_client: hal_client, parsed_json: hash_data),
           curie_resolver: curie_resolver)
end

.new_from_link_entry(options) ⇒ Object

Create a new Link using an entry from the ‘_links’ section of a HAL document

options - name parameters

:hash_entry - a hash containing keys :rel (string) and :data (hash from a '_links' entry)
:hal_client - an instance of HalClient
:curie_resolver - An instance of CurieResolver (used to resolve curied rels)
:base_url - Base url for resolving relative links in hash_entry (probably the parent

document’s “self” link)



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# File 'lib/hal_client/link.rb', line 51

def self.new_from_link_entry(options)
  hash_entry = options[:hash_entry]
  hal_client = options[:hal_client]
  curie_resolver = options[:curie_resolver]
  base_url = options[:base_url]

  rel = hash_entry[:rel]
  hash_data = hash_entry[:data]
  href = (base_url + hash_data['href']).to_s

  if hash_data['templated']
    Link.new(rel: rel,
             template: Addressable::Template.new(href),
             curie_resolver: curie_resolver)
  else
    Link.new(rel: rel,
             target: Representation.new(hal_client: hal_client, href: href),
             curie_resolver: curie_resolver)
  end
end

Instance Method Details

#==(other) ⇒ Object Also known as: eql?

Links with the same href, same rel value, and the same ‘templated’ value are considered equal Otherwise, they are considered unequal



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# File 'lib/hal_client/link.rb', line 116

def ==(other)
  if other.respond_to?(:raw_href) &&
     other.respond_to?(:fully_qualified_rel) &&
     other.respond_to?(:templated?)
    (raw_href == other.raw_href) &&
      (fully_qualified_rel == other.fully_qualified_rel) &&
      (templated? == other.templated?)
  else
    false
  end
end

#fully_qualified_rel ⇒ Object 



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# File 'lib/hal_client/link.rb', line 105

def fully_qualified_rel
  curie_resolver.resolve(literal_rel)
end

#hash ⇒ Object

Differing Representations or Addressable::Templates with matching hrefs will get matching hash values, since we are using raw_href and not the objects themselves when computing hash



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# File 'lib/hal_client/link.rb', line 132

def hash
  [fully_qualified_rel, raw_href, templated?].hash
end

#raw_href ⇒ Object

Returns the URL of the resource this link references. In the case of a templated link, this is the unresolved url template pattern.



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# File 'lib/hal_client/link.rb', line 101

def raw_href
  templated? ? template.pattern : target.href
end

#templated? ⇒ Boolean

Returns true for a templated link, false for an ordinary (non-templated) link



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# File 'lib/hal_client/link.rb', line 110

def templated?
  !template.nil?
end