Class: Praxis::MediaType::FieldResolver

Inherits:
Object
  • Object
show all
Defined in:
lib/praxis/media_type.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ FieldResolver

Returns a new instance of FieldResolver.



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# File 'lib/praxis/media_type.rb', line 94

def initialize
  @history = Hash.new do |hash,key|
    hash[key] = Hash.new
  end
end

Instance Attribute Details

#history ⇒ Object (readonly)

Returns the value of attribute history.



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# File 'lib/praxis/media_type.rb', line 92

def history
  @history
end

Class Method Details

.resolve(type, fields) ⇒ Object 



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# File 'lib/praxis/media_type.rb', line 88

def self.resolve(type,fields)
  self.new.resolve(type,fields)
end

Instance Method Details

#deep_merge(target, source) ⇒ Object

perform a deep recursive *in place* merge form all values in source onto target

note: can not use ActiveSupport’s Hash#deep_merge! because it does not properly do a recursive ‘deep_merge!`, but instead does `deep_merge`, which destroys the self-referential behavior of field hashes.

note: unlike Hash#merge, doesn’t take a block.



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# File 'lib/praxis/media_type.rb', line 153

def deep_merge(target, source)
  source.each do |current_key, source_value|
    target_value = target[current_key]

    target[current_key] = if target_value.is_a?(Hash) && source_value.is_a?(Hash)
      deep_merge(target_value, source_value)
    else
      source_value
    end
  end
  target
end

#resolve(type, fields) ⇒ Object 



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# File 'lib/praxis/media_type.rb', line 100

def resolve(type,fields)
  history_key = fields
  history_type = type
  if fields.kind_of?(Array)
    loop do
      type = type.member_attribute.type
      fields = fields.first
      break unless fields.kind_of?(Array)
    end
  end

  return true if fields == true

  if history[history_type].include? history_key
    return history[history_type][history_key]
  end

  result = history[history_type][history_key] = {}


  fields.each do |name, sub_fields|
    # skip links and do them below
    next if name == :links && defined?(type::Links)

    new_type = type.attributes[name].type
    result[name] = resolve(new_type, sub_fields)
  end

  # now to tackle whatever links there may be
  if (links_fields = fields[:links])
    resolved_links = resolve_links(type::Links, links_fields)
    self.deep_merge(result, resolved_links)
  end

  result
end

#resolve_links(links_type, links) ⇒ Object 



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# File 'lib/praxis/media_type.rb', line 137

def resolve_links(links_type, links)
  links.each_with_object({}) do |(name, link_fields), hash|
    using = links_type.links[name]
    new_type = links_type.attributes[name].type
    hash[using] = resolve(new_type, link_fields)
  end
end