Pseudo-Hierarchical Folders/Directories

You can simulate a hierarchical structure in OpenStack Object Storage by following a few guidelines. Object names must contain the forward slash character / as a path element separator and also create directory marker objects; then they will be able to traverse this nested structure with the new path query parameter. This can best be illustrated by example:

[Note]Note

For the purposes of this example, the container where the objects reside is called backups. All objects in this example start with a prefix of photos and should NOT be confused with the container name. In the example, the full URI of the me.jpg file would be https://storage.swiftdrive.com/v1/CF_xer7_343/backups/photos/me.jpg

Example 3.19. Pseudo-Hierarchical Folders/Directories

In the example, the following real objects are uploaded to the storage system with names representing their full filesystem path:

  photos/animals/dogs/poodle.jpg
  photos/animals/dogs/terrier.jpg
  photos/animals/cats/persian.jpg
  photos/animals/cats/siamese.jpg
  photos/plants/fern.jpg
  photos/plants/rose.jpg
  photos/me.jpg

To take advantage of this feature, the directory marker objects must also be created to represent the appropriate directories. The following additional objects need to be created. A good convention would be to create these as zero- or one-byte files with a Content-Type of application/directory.

  photos/animals/dogs
  photos/animals/cats
  photos/animals
  photos/plants
  photos

Now issuing a GET request against the container name coupled with the path query parameter of the directory to list can traverse these directories. Only the request line and results are depicted below excluding other request/response headers.

  GET /v1/AccountString/backups?path=photos HTTP/1.1
  Host: storage.swiftdrive.com
  X-Auth-Token: eaaafd18-0fed-4b3a-81b4-663c99ec1cbb
                    
  photos/animals
  photos/cats
  photos/me.jpg

To traverse down into the animals directory, specify that path.

  GET /v1/AccountString/backups?path=photos/animals
  Host: storage.swiftdrive.com
  X-Auth-Token: eaaafd18-0fed-4b3a-81b4-663c99ec1cbb
                    
  photos/animals/dogs
  photos/animals/cats

By combining this path query parameter with the format query parameter, users will be able to easily distinguish between virtual folders/directories by Content-Type and build interfaces that allow traversal of the pseudo-nested structure.

You can also use a delimiter parameter to represent a nested directory hierarchy without the need for the directory marker objects. You can use any single character as a delimiter. The listings can return virtual directories - they are virtual in that they don't actually represent real objects. like the directory markers, though, they will have a content-type of application/directory and be in a subdir section of json and xml results.

If you have the following objects—photos/photo1, photos/photo2, movieobject, videos/movieobj4—in a container, your delimiter parameter query using slash (/) would give you photos, movieobject, videos.

GET /v1/acct/container?delimiter=/
Host: storage.swiftdrive.com
X-Auth-Token: eaaafd18-0fed-4b3a-81b4-663c99ec1cbb
Legal notices