Module: HalInterpretation::Dsl

Defined in:
lib/hal_interpretation/dsl.rb

Instance Method Summary collapse

Instance Method Details

#extract(attr_name, opts = {}) ⇒ Object

Declare that an attribute should be extract from the HAL document.

attr_name - name of attribute on model to extract

opts - hash of named arguments to method

:from - JSON path from which to get the value for
  attribute. Default: "/#{attr_name}".

:with - Callable that can extract the value when
  passed a HalClient::Representation of the item.

:coercion - callable with which the raw value should be
  transformed before being stored.



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# File 'lib/hal_interpretation/dsl.rb', line 25

def extract(attr_name, opts={})
  extractor_opts = {
    attr: attr_name,
    location: opts.fetch(:from) { "/#{attr_name}" }
  }
  extractor_opts[:extraction_proc] = opts.fetch(:with) if opts[:with]
  extractor_opts[:coercion] = opts[:coercion] if opts[:coercion]

  extractors << Extractor.new(extractor_opts)
end

#extract_link(attr_name, opts = {}) ⇒ Object

Declare that an attribute should be extracted the HAL document’s links (or embeddeds) where only one instance of that link type is legal.

attr_name - name of the attribute on the model to extract

opts - hash of named arguments

:rel - rel of link to extract. Default: attr_name

:coercion - callable with which the raw URL should transformed
before being stored in the model

Examples

extract_link :author_website,
             rel: "http://xmlns.com/foaf/0.1/homepage"

extracts the target of the ‘…/homepage` link and stores in the `author_website` attribute of the model.

extract_link :parent, rel: "up",
              coercion: ->(url) {
                Blog.find id_from_url(u)
              }

looks up the blog pointed to by the ‘up` link and stores that model instance in the `parent` association of the model we are interpreting.



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# File 'lib/hal_interpretation/dsl.rb', line 65

def extract_link(attr_name, opts={})
  orig_coercion = opts[:coercion] || IDENTITY
  adjusted_opts = opts.merge coercion: ->(urls) {
    fail "Too many instances (expected exactly 1, found #{urls.count})" if
      urls.count > 1

    instance_exec urls.first, &orig_coercion
  }

  extract_links attr_name, adjusted_opts
end

#extract_links(attr_name, opts = {}) ⇒ Object

Declare that an attribute should be extracted the HAL document’s links (or embeddeds).

attr_name - name of the attribute on the model to extract

opts - hash of named arguments

:rel - rel of link to extract. Default: attr_name

:coercion - callable with which the raw URL should transformed
before being stored in the model

Examples

extract_links :author_websites,
              rel: "http://xmlns.com/foaf/0.1/homepage"

extracts the targets of the ‘…/homepage` link and stores in the `author_websites` attribute of the model.

extract_links :parents, rel: "up",
              coercion: ->(urls) {
                urls.map { |u| Blog.find id_from_url(u) }
              }

looks up the blogs pointed to by the ‘up` links and stores that collection of model instances in the `parents` association of the model we are interpreting.



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# File 'lib/hal_interpretation/dsl.rb', line 105

def extract_links(attr_name, opts={})
  rel = opts.fetch(:rel) { attr_name }.to_s
  path = "/_links/" + json_path_escape(rel)

  stringify_href = ->(string_or_uri_tmpl) {
    if string_or_uri_tmpl.respond_to? :pattern
      string_or_uri_tmpl.pattern
    else
      string_or_uri_tmpl.to_str
    end
  }

  extract attr_name, from: path,
          with: ->(r){ r.raw_related_hrefs(rel){[]}.map &stringify_href },
          coercion: opts[:coercion]
end

#item_class(klass) ⇒ Object

Declare the class of models this interpreter builds.



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# File 'lib/hal_interpretation/dsl.rb', line 4

def item_class(klass)
  define_method(:item_class) do
    klass
  end
end