Class: Rubrik::Document

Inherits:
Object
  • Object
show all
Extended by:
T::Sig
Defined in:
lib/rubrik/document.rb,
lib/rubrik/document/increment.rb,
lib/rubrik/document/serialize_object.rb

Defined Under Namespace

Modules: Increment, SerializeObject

Constant Summary collapse

CONTENTS_PLACEHOLDER = 
Object.new.freeze
BYTE_RANGE_PLACEHOLDER = 
Object.new.freeze
SIGNATURE_SIZE = 
8_192

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(input) ⇒ Document

Returns a new instance of Document.



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# File 'lib/rubrik/document.rb', line 32

def initialize(input)
  self.io = input
  self.objects = PDF::Reader::ObjectHash.new(input)

  self.last_object_id = objects.trailer[:Size] - 1
  self.first_free_object_id = find_first_free_object_id

  self.modified_objects = []

  fetch_or_create_interactive_form!
end

Instance Attribute Details

#first_free_object_id ⇒ Object

Returns the value of attribute first_free_object_id.



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# File 'lib/rubrik/document.rb', line 21

def first_free_object_id
  @first_free_object_id
end

#io ⇒ Object

Returns the value of attribute io.



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# File 'lib/rubrik/document.rb', line 15

def io
  @io
end

#last_object_id ⇒ Object

Returns the value of attribute last_object_id.



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# File 'lib/rubrik/document.rb', line 27

def last_object_id
  @last_object_id
end

#modified_objects ⇒ Object

Returns the value of attribute modified_objects.



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# File 'lib/rubrik/document.rb', line 24

def modified_objects
  @modified_objects
end

#objects ⇒ Object

Returns the value of attribute objects.



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# File 'lib/rubrik/document.rb', line 18

def objects
  @objects
end

Instance Method Details

#add_signature_field ⇒ Object

Returns the reference of the Signature Value dictionary.



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# File 'lib/rubrik/document.rb', line 46

def add_signature_field
  # To add an signature to the PDF, we need the following structure
  # Interactive Form -> Signature Field -> Signature Value
  signature_value_id = assign_new_object_id!
  modified_objects << {
    id: signature_value_id,
    value: {
      Type: :Sig,
      Filter: :"Adobe.PPKLite",
      SubFilter: :"adbe.pkcs7.detached",
      Contents: CONTENTS_PLACEHOLDER,
      ByteRange: BYTE_RANGE_PLACEHOLDER
    }
  }

  first_page_reference = T.must(objects.page_references[0])

  # create signature field
  signature_field_id = assign_new_object_id!
  modified_objects << {
    id: signature_field_id,
    value: {
      T: "Signature-#{SecureRandom.hex(2)}",
      FT: :Sig,
      V: signature_value_id,
      Type: :Annot,
      Subtype: :Widget,
      Rect: [0, 0, 0, 0],
      F: 4,
      P: first_page_reference
    }
  }

  first_page = objects.fetch(first_page_reference)
  annots = first_page[:Annots]

  if annots.is_a?(PDF::Reader::Reference)
    new_annots = objects.fetch(annots).dup
    new_annots << signature_field_id

    modified_objects << {id: annots, value: new_annots}
  else
    new_first_page = first_page.dup
    (new_first_page[:Annots] ||= []) << signature_field_id

    modified_objects << {id: first_page_reference, value: new_first_page}
  end

  fields_entry = interactive_form[:Fields]
  if fields_entry.is_a?(PDF::Reader::Reference)
    new_fields_array = objects.fetch(fields_entry).dup
    new_fields_array << signature_field_id

    modified_objects << {id: fields_entry, value: new_fields_array}
  else
    (interactive_form[:Fields] ||= []) << signature_field_id
  end

  signature_value_id
end