Class: HalClient::Representation

Inherits:
Object
  • Object
show all
Extended by:
Forwardable
Defined in:
lib/hal_client/representation.rb

Overview

HAL representation of a single resource. Provides access to properties, links and embedded representations.

Instance Method Summary collapse

Constructor Details

#initialize(*args) ⇒ Representation

Create a new Representation

parsed_json - A hash structure representing a single HAL document. href - The href of this representation. hal_client - The HalClient instance to use when navigating.

Signature

initialize(hal_client, parsed_json)
initialize(parsed_json, hal_client)

Initialize this representation with a parsed json document and a hal_client with which to make requests.

initialize(href, hal_client)

Initialize this representation with an href and a hal_client with which to make requests. Any attempt to retrieve properties or related representations will result in the href being dereferenced.

initialize(href)

Initialize this representation with an href. The representation will not be able to make requests to dereference itself but this can still be useful in test situations to maintain a uniform interface.

initialize(parse_json)

Initializes representation that cannot request related representations.



48
49
50
51
52
53
54
55
56
57
58
 
# File 'lib/hal_client/representation.rb', line 48

def initialize(*args)
  (raise ArgumentError, "wrong number of arguments (#{args.size} for 1 or 2)") if
    args.size > 2

  @raw = args.find {|it| (it.respond_to? :has_key?) &&  (it.respond_to? :fetch) }
  @hal_client = args.find {|it| HalClient === it }

  if @raw.nil?
    @href = args.find {|it| it.respond_to? :downcase }
  end
end

Instance Method Details

#[](name_or_rel) ⇒ Object

Returns the value of the specified property or representations of resources related via the specified link rel or nil

name_or_rel - The name of property or link rel of interest



109
110
111
112
 
# File 'lib/hal_client/representation.rb', line 109

def [](name_or_rel)
  item_key = name_or_rel
  fetch(item_key, nil)
end

#fetch(name_or_rel, default = MISSING, &default_proc) ⇒ Object

Returns the value of the specified property or representations of resources related via the specified link rel or the specified default value.

name_or_rel - The name of property or link rel of interest default - an optional object that should be return if the specified property or link does not exist default_proc - an option proc that will be called with name to produce default value if the specified property or link does not exist

Raises KeyError if the specified property or link does not exist and no default nor default_proc is provided.



96
97
98
99
100
101
102
103
 
# File 'lib/hal_client/representation.rb', line 96

def fetch(name_or_rel, default=MISSING, &default_proc)
  item_key = name_or_rel
  default_proc ||= ->(_){default} if default != MISSING

  property(item_key) {
    related(item_key, &default_proc)
  }
end

#has_related?(link_rel) ⇒ Boolean

Returns true if this representation contains a link (including embedded links) whose rel is link_rel.

link_rel - The link rel of interest

Returns:

  • (Boolean) 


118
119
120
121
122
123
 
# File 'lib/hal_client/representation.rb', line 118

def has_related?(link_rel)
  _ = related link_rel
  true
rescue KeyError
  false
end

#href ⇒ Object

Returns the URL of the resource this representation represents.



79
80
81
 
# File 'lib/hal_client/representation.rb', line 79

def href
  @href ||= link_section.fetch("self").fetch("href")
end

#property(name, default = MISSING, &default_proc) ⇒ Object

Returns The value of the specified property or the specified default value.

name - The name of property of interest default - an optional object that should be return if the specified property does not exist default_proc - an option proc that will be called with name to produce default value if the specified property does not exist

Raises KeyError if the specified property does not exist and no default nor default_proc is provided.



72
73
74
75
76
 
# File 'lib/hal_client/representation.rb', line 72

def property(name, default=MISSING, &default_proc)
  default_proc ||= ->(_){ default} if default != MISSING

  raw.fetch(name.to_s, &default_proc)
end

#related(link_rel, options = {}, &default_proc) ⇒ Object

Returns representations of resources related via the specified link rel or the specified default value.

link_rel - The link rel of interest options - optional keys and values with which to expand any templated links that are encountered default_proc - an option proc that will be called with name to produce default value if the specified property or link does not exist

Raises KeyError if the specified link does not exist and no default_proc is provided.



137
138
139
140
141
142
143
144
145
146
147
148
149
150
 
# File 'lib/hal_client/representation.rb', line 137

def related(link_rel, options = {}, &default_proc)
  default_proc ||= ->(link_rel){
    raise KeyError, "No resources are related via `#{link_rel}`"
  }

  embedded = embedded_or_nil(link_rel)
  linked = linked_or_nil(link_rel, options)

  if !embedded.nil? or !linked.nil?
    RepresentationSet.new (Array(embedded) + Array(linked))
  else
    default_proc.call link_rel
  end
end

#related_hrefs(link_rel, options = {}, &default_proc) ⇒ Object

Returns urls of resources related via the specified link rel or the specified default value.

link_rel - The link rel of interest options - optional keys and values with which to expand any templated links that are encountered default_proc - an option proc that will be called with name to produce default value if the specified property or link does not exist

Raises KeyError if the specified link does not exist and no default_proc is provided.



164
165
166
167
 
# File 'lib/hal_client/representation.rb', line 164

def related_hrefs(link_rel, options={}, &default_proc)
  related(link_rel, options, &default_proc).
    map(&:href)
end

#to_s ⇒ Object

Returns a short human readable description of this representation.



171
172
173
 
# File 'lib/hal_client/representation.rb', line 171

def to_s
  "#<" + self.class.name + ": " + href + ">"
end