Class: DPN::Bagit::SerializedBag

Inherits:
Object
  • Object
show all
Defined in:
lib/dpn/bagit/serialized_bag.rb

Overview

A wrapper for a serialized Bag-It bag on disk. Once created, will not change with changes made to the underlying filesystem bag; in that case, a new object should be created.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(path) ⇒ SerializedBag

Create a SerializedBag

Parameters:

  • path (String) —

    Path to the file.

Raises:

  • (ArgumentError) 


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# File 'lib/dpn/bagit/serialized_bag.rb', line 15

def initialize(path)
  raise ArgumentError, "File does not exist!" unless File.exist?(path)
  @location = path
end

Instance Attribute Details

#location ⇒ String (readonly)

Returns The location, which can be relative or absolute.

Returns:

  • (String) —

    The location, which can be relative or absolute.



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# File 'lib/dpn/bagit/serialized_bag.rb', line 9

class DPN::Bagit::SerializedBag

  attr_reader :location

  # Create a SerializedBag
  # @param path [String] Path to the file.
  def initialize(path)
    raise ArgumentError, "File does not exist!" unless File.exist?(path)
    @location = path
  end

  # Returns the file name for the serialized bag, without it's extension.
  # @return [String] name
  def name
    @name ||= File.basename(location, File.extname(location))
  end

  # Returns the directory path to the serialized bag.
  # @return [String] path
  def path
    @path ||= File.dirname(location)
  end

  # Returns the size of the serialized bag (in bytes).
  # @return [Fixnum] size
  def size
    File.size(location)
  end

  # Returns the fixity of the serialized version of the bag.
  # @param algorithm [Symbol] The algorithm to use for calculation.
  # @return [String] fixity
  def fixity(algorithm)
    @cachedFixity ||= begin
      case algorithm
      when :sha256
        digest = Digest::SHA256
      else
        raise ArgumentError, "Unknown algorithm."
      end
      digest.file(location).hexdigest
    end
  end

  # Unserialize the bag into the local filesystem.  This object
  # is unchanged.  Requires sufficient permissions and disk space.
  # @return [DPN::Bagit::Bag] A bag made from the unserialized object.
  def unserialize!
    `/bin/tar -xf #{location} -C #{path} 2> /dev/null`
    raise RuntimeError, "cannot untar #{location}" unless $?.success?
    DPN::Bagit::Bag.new(File.join(path, name))
  end
end

Instance Method Details

#fixity(algorithm) ⇒ String

Returns the fixity of the serialized version of the bag.

Parameters:

  • algorithm (Symbol) —

    The algorithm to use for calculation.

Returns:

  • (String) —

    fixity



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# File 'lib/dpn/bagit/serialized_bag.rb', line 41

def fixity(algorithm)
  @cachedFixity ||= begin
    case algorithm
    when :sha256
      digest = Digest::SHA256
    else
      raise ArgumentError, "Unknown algorithm."
    end
    digest.file(location).hexdigest
  end
end

#name ⇒ String

Returns the file name for the serialized bag, without it’s extension.

Returns:

  • (String) —

    name



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# File 'lib/dpn/bagit/serialized_bag.rb', line 22

def name
  @name ||= File.basename(location, File.extname(location))
end

#path ⇒ String

Returns the directory path to the serialized bag.

Returns:

  • (String) —

    path



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# File 'lib/dpn/bagit/serialized_bag.rb', line 28

def path
  @path ||= File.dirname(location)
end

#size ⇒ Fixnum

Returns the size of the serialized bag (in bytes).

Returns:

  • (Fixnum) —

    size



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# File 'lib/dpn/bagit/serialized_bag.rb', line 34

def size
  File.size(location)
end

#unserialize! ⇒ DPN::Bagit::Bag

Unserialize the bag into the local filesystem. This object is unchanged. Requires sufficient permissions and disk space.

Returns:

Raises:

  • (RuntimeError) 


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# File 'lib/dpn/bagit/serialized_bag.rb', line 56

def unserialize!
  `/bin/tar -xf #{location} -C #{path} 2> /dev/null`
  raise RuntimeError, "cannot untar #{location}" unless $?.success?
  DPN::Bagit::Bag.new(File.join(path, name))
end