Orchard is a Ruby library for working with Pairtrees, a filesystem hierarchy mapping identifiers to object directories.

More information can be found at:

Pairtrees for Object Storage
https://confluence.ucop.edu/display/Curation/PairTree

Orchard requires Ruby 1.9.

gem install orchard

Orchard::Pairtree.encode('ark:/13030/xt12t3')
# => ark+=13030=xt12t3

Orchard::Pairtree.decode('ark+=13030=xt12t3')
# => ark:/13030/xt12t3

Orchard::Pairtree.id_to_ppath('ark:/13030/xt12t3')
# => ar/k+/=1/30/30/=x/t1/2t/3

Orchard::Pairtree.ppath_to_id('ar/k+/=1/30/30/=x/t1/2t/3')
# => ark:/13030/xt12t3

Orchard::Pairtree.iterate('repo/pairtree_root/', {:raise_errors => true}) do |path|
  puts path
end
# => /absolute_path/repo/pairtree_root/ab/cd/e/object
...
# => /absolute_path/repo/pairtree_root/xy/z/object

Erik Hetzner for contributions.
Ben O'Steen (this module is a semi-port of his Python Pairtree module, http://github.com/benosteen/pairtree)