Class: Praxis::Renderer

Inherits:
Object
  • Object
show all
Defined in:
lib/praxis-blueprints/renderer.rb

Defined Under Namespace

Classes: CircularRenderingError

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(include_nil: false) ⇒ Renderer

Returns a new instance of Renderer.



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# File 'lib/praxis-blueprints/renderer.rb', line 22

def initialize(include_nil: false)
  @cache = Hash.new do |hash, key|
    hash[key] = {}
  end

  @include_nil = include_nil
end

Instance Attribute Details

#cache ⇒ Object (readonly)

Returns the value of attribute cache.



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# File 'lib/praxis-blueprints/renderer.rb', line 5

def cache
  @cache
end

#include_nil ⇒ Object (readonly)

Returns the value of attribute include_nil.



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# File 'lib/praxis-blueprints/renderer.rb', line 4

def include_nil
  @include_nil
end

Instance Method Details

#_render(object, fields, view = nil, context: Attributor::DEFAULT_ROOT_CONTEXT) ⇒ Object 



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# File 'lib/praxis-blueprints/renderer.rb', line 58

def _render(object, fields, view = nil, context: Attributor::DEFAULT_ROOT_CONTEXT)
  if fields == true
    return case object
           when Attributor::Dumpable
             object.dump
           else
             object
           end
  end

  notification_payload = {
    blueprint: object,
    fields: fields,
    view: view
  }

  ActiveSupport::Notifications.instrument 'praxis.blueprint.render', notification_payload do
    fields.each_with_object({}) do |(key, subfields), hash|
      begin
        value = object._get_attr(key)
      rescue => e
        raise Attributor::DumpError, context: context, name: key, type: object.class, original_exception: e
      end

      if value.nil?
        hash[key] = nil if self.include_nil
        next
      end

      if subfields == true
        hash[key] = case value
                    when Attributor::Dumpable
                      value.dump
                    else
                      value
                    end
      else
        new_context = context + [key]
        hash[key] = render(value, subfields, context: new_context)
      end
    end
  end
end

#render(object, fields, view = nil, context: Attributor::DEFAULT_ROOT_CONTEXT) ⇒ Object

Renders an object using a given list of fields.

Parameters:

  • object (Object) —

    the object to render

  • fields (Hash) —

    the correct set of fields, as from FieldExpander



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# File 'lib/praxis-blueprints/renderer.rb', line 42

def render(object, fields, view = nil, context: Attributor::DEFAULT_ROOT_CONTEXT)
  if fields.is_a? Array
    sub_fields = fields[0]
    object.each_with_index.collect do |sub_object, i|
      sub_context = context + ["at(#{i})"]
      render(sub_object, sub_fields, view, context: sub_context)
    end
  elsif object.is_a? Praxis::Blueprint
    @cache[object.object_id][fields.object_id] ||= _render(object, fields, view, context: context)
  else
    _render(object, fields, view, context: context)
  end
rescue SystemStackError
  raise CircularRenderingError.new(object, context)
end

#render_collection(collection, member_fields, view = nil, context: Attributor::DEFAULT_ROOT_CONTEXT) ⇒ Object

Renders an a collection using a given list of per-member fields.

Parameters:

  • object (Object) —

    the object to render

  • fields (Hash) —

    the set of fields, as from FieldExpander, to apply to each member of the collection.



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# File 'lib/praxis-blueprints/renderer.rb', line 34

def render_collection(collection, member_fields, view = nil, context: Attributor::DEFAULT_ROOT_CONTEXT)
  render(collection, [member_fields], view, context: context)
end