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.

Constant Summary collapse

RESERVED_PROPERTIES =

Collection of reserved properties tools.ietf.org/html/draft-kelly-json-hal-07#section-4.1

['_links', '_embedded'].freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options) ⇒ Representation

Create a new Representation

options - name parameters

: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.



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# File 'lib/hal_client/representation.rb', line 25

def initialize(options)
  @raw = options[:parsed_json]
  @hal_client = options[:hal_client]
  @href = options[:href]

  (fail ArgumentError, "Either parsed_json or href must be provided") if
    @raw.nil? && @href.nil?

  (fail InvalidRepresentationError, "Invalid HAL representation: #{raw.inspect}") if
    @raw && ! hashish?(@raw)
end

Instance Attribute Details

#hal_client ⇒ Object (readonly)

Internal: Returns the HalClient used to retrieve this representation



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# File 'lib/hal_client/representation.rb', line 322

def hal_client
  @hal_client
end

Instance Method Details

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



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# File 'lib/hal_client/representation.rb', line 290

def ==(other)
  if href && other.respond_to?(:href)
    href == other.href
  elsif other.respond_to?(:raw)
    @raw == other.raw
  else
    false
  end
end

#[](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



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# File 'lib/hal_client/representation.rb', line 138

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

#all_links ⇒ Object 



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# File 'lib/hal_client/representation.rb', line 180

def all_links
  result = Set.new
  base_url = Addressable::URI.parse(href || "")

  embedded_entries = flatten_section(raw.fetch("_embedded", {}))
  result.merge(embedded_entries.map do |entry|
    Link.new_from_embedded_entry(hash_entry: entry,
                                 hal_client: hal_client,
                                 curie_resolver: namespaces,
                                 base_url: base_url)
  end)

  link_entries = flatten_section(raw.fetch("_links", {}))
  result.merge(link_entries.map { |entry|
    Link.new_from_link_entry(hash_entry: entry,
                             hal_client: hal_client,
                             curie_resolver: namespaces,
                             base_url: base_url) })

  result
end

#as_enum ⇒ Object

Returns an Enumerable of the items in this collection resource if this is an rfc 6573 collection.

Raises HalClient::NotACollectionError if this is not a collection resource.



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# File 'lib/hal_client/representation.rb', line 250

def as_enum
  Collection.new(self)
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.



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# File 'lib/hal_client/representation.rb', line 125

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

#hash ⇒ Object 



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# File 'lib/hal_client/representation.rb', line 282

def hash
  if href
    href.hash
  else
    @raw.hash
  end
end

#href ⇒ Object

Returns the URL of the resource this representation represents.



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

def href
  @href ||= raw
          .fetch("_links",{})
          .fetch("self",{})
          .fetch("href",nil)
end

#patch(data, options = {}) ⇒ Object

Patchs a Representation or String to this resource. Causes this representation to be reloaded the next time it is used.

data - a String or an object that responds to #to_hal options - set of options to pass to ‘HalClient#patch`



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# File 'lib/hal_client/representation.rb', line 64

def patch(data, options={})
  @hal_client.patch(href, data, options).tap do
    reset
  end
end

#post(data, options = {}) ⇒ Object

Posts a Representation or String to this resource. Causes this representation to be reloaded the next time it is used.

data - a String or an object that responds to #to_hal options - set of options to pass to ‘HalClient#post`



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# File 'lib/hal_client/representation.rb', line 42

def post(data, options={})
  @hal_client.post(href, data, options).tap do
    reset
  end
end

#properties ⇒ Object

Returns a Hash including the key-value pairs of all the properties

in the resource. It does not include HAL's reserved
properties (`_links` and `_embedded`).



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# File 'lib/hal_client/representation.rb', line 100

def properties
  raw.reject { |k, _| RESERVED_PROPERTIES.include? k }
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.



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# File 'lib/hal_client/representation.rb', line 91

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

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

#property?(name) ⇒ Boolean Also known as: has_property?

Returns true if this representation contains the specified property.

name - the name of the property to check

Returns:

  • (Boolean) 


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# File 'lib/hal_client/representation.rb', line 74

def property?(name)
  raw.key? name
end

#put(data, options = {}) ⇒ Object

Puts a Representation or String to this resource. Causes this representation to be reloaded the next time it is used.

data - a String or an object that responds to #to_hal options - set of options to pass to ‘HalClient#put`



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# File 'lib/hal_client/representation.rb', line 53

def put(data, options={})
  @hal_client.put(href, data, options).tap do
    reset
  end
end

#raw ⇒ Object

Internal: Returns parsed json document



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# File 'lib/hal_client/representation.rb', line 302

def raw
  if @raw.nil? && @href
    (fail "unable to make requests due to missing hal client") unless hal_client

    response = hal_client.get(@href)

    unless response.is_a?(Representation)
      error_message = "Response body wasn't a valid HAL document:\n\n"
      error_message += response.body
      raise InvalidRepresentationError.new(error_message)
    end

    @raw ||= response.raw
  end

  @raw
end

#raw_related_hrefs(link_rel, &default_proc) ⇒ Object

Returns values of the href member of links and the URL of embedded representations related via the specified link rel. The only difference between this and #related_hrefs is that this method makes no attempt to expand templated links. For templated links the returned collection will include the template pattern as encoded in the HAL document.

link_rel - The link rel of interest 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.



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# File 'lib/hal_client/representation.rb', line 233

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

  embedded = embedded(link_rel) { nil }
  linked = links.hrefs(link_rel) { nil }
  return default_proc.call(link_rel) if embedded.nil? and linked.nil?

  Array(linked) + Array(embedded).map(&:href)
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.



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# File 'lib/hal_client/representation.rb', line 168

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

  embedded = embedded(link_rel) { nil }
  linked = linked(link_rel, options) { nil }
  return default_proc.call(link_rel) if embedded.nil? and linked.nil?

  RepresentationSet.new (Array(embedded) + Array(linked))
end

#related?(link_rel) ⇒ Boolean Also known as: has_related?

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) 


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# File 'lib/hal_client/representation.rb', line 147

def related?(link_rel)
  _ = related link_rel
  true

rescue KeyError
  false
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.



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# File 'lib/hal_client/representation.rb', line 214

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

#reset ⇒ Object

Resets this representation such that it will be requested from the upstream on it’s next use.



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# File 'lib/hal_client/representation.rb', line 265

def reset
  @href = href # make sure we have the href
  @raw = nil
end

#to_enum(method = :each, *args, &blk) ⇒ Object

Returns an Enumerator of the items in the collection resource if this is an rfc 6573 collection.

Raises HalClient::NotACollectionError if this is not a collection resource.



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# File 'lib/hal_client/representation.rb', line 259

def to_enum(method=:each, *args, &blk)
  as_enum.to_enum(method, *args, &blk)
end

#to_json ⇒ Object Also known as: to_hal

Returns the raw json representation of this representation



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# File 'lib/hal_client/representation.rb', line 277

def to_json
  MultiJson.dump(raw)
end

#to_s ⇒ Object

Returns a short human readable description of this representation.



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# File 'lib/hal_client/representation.rb', line 272

def to_s
  "#<" + self.class.name + ": " + (href || "ANONYMOUS")  + ">"
end