Method: OcflTools::OcflValidator#verify_fixity

Defined in:
lib/ocfl_tools/ocfl_validator.rb

#verify_fixity(inventory_file: "#{@ocfl_object_root}/inventory.json", digest: 'md5') ⇒ OcflTools::OcflResults

Performs checksum validation of files listed in the inventory’s fixity block.

Parameters:

  • inventory_file (Pathname) (defaults to: "#{@ocfl_object_root}/inventory.json") —

    fully-qualified path to a valid OCFL inventory.json.

  • digest (String) (defaults to: 'md5') —

    string value of the algorithm to use for this fixity check. This value must exist as a key in the object’s fixity block.

Returns:



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# File 'lib/ocfl_tools/ocfl_validator.rb', line 64

def verify_fixity(inventory_file: "#{@ocfl_object_root}/inventory.json", digest: 'md5')
  # Gets the appropriate fixity block, calls compare_hash_checksums

  begin
    @inventory = load_inventory(inventory_file)
  rescue OcflTools::Errors::ValidationError
    @my_results.error('E210', 'verify_fixity', "Unable to process inventory file #{inventory_file}.")
    return @my_results
  end

  # Since fixity blocks are not required to be complete, we just validate what's there.
  # So get the fixity block, flip it, expand it, checksum it against the same files on disk.

  if @inventory.fixity.empty?
    @my_results.error('E111', "verify_fixity #{digest}", "No fixity block in #{inventory_file}!")
    return @my_results
  end

  unless @inventory.fixity.key?(digest)
    @my_results.error('E111', "verify_fixity #{digest}", "Requested algorithm #{digest} not found in fixity block.")
    return @my_results
  end

  fixity_checksums = OcflTools::Utils::Files.invert_and_expand_and_prepend(@inventory.fixity[digest], @ocfl_object_root)

  my_files_on_disk = fixity_checksums.keys

  # Warn if there are less files in requested fixity block than in manifest.
  if @inventory.manifest.keys.size > fixity_checksums.keys.size
    missing_files = @inventory.manifest.keys.size - fixity_checksums.keys.size
    @my_results.warn(
      'W111',
      "verify_fixity #{digest}",
      "#{missing_files} files in manifest are missing from fixity block."
    )
  end

  # check these files exist on disk before trying to make checksums!
  my_files_on_disk.each do |file|
    unless File.file? file
      @my_results.error('E111', "verify_fixity #{digest}", "File #{file} in fixity block not found on disk.")
      my_files_on_disk.delete(file)
    end
  end

  disk_checksums = OcflTools::Utils::Files.create_digests(my_files_on_disk, digest)

  # And now we can compare values!
  OcflTools::Utils.compare_hash_checksums(
    disk_checksums: disk_checksums,
    inventory_checksums: fixity_checksums,
    results: @my_results,
    context: "verify_fixity #{digest}"
  )
end