h5serv supports the REST convention of HATEOAS or Hypermedia as the Engine of Application State. The idea is (see http://en.wikipedia.org/wiki/HATEOS for a full explanation) is that each response include links to related resources related to the requested resource.

For example, consider the request for a dataset: GET /datasets/<id>. The response will be a JSON representation of the dataset describing it’s type, shape, and other aspects. Related resources to the dataset would include:

  • the dataset’s attributes
  • the dataset’s value
  • the dataset collection of the domain
  • the root group of the domain the dataset is in
  • the domain resource

So the GET /datasets/<id> response includes a key hrefs that contains an a JSON array. Each array element has a key: href - the related resource, and a key: rel that denotes the type of relation. Example:

"hrefs": [
    {"href": "http://tall.test.hdfgroup.org/datasets/<id>", "rel": "self"},
    {"href": "http://tall.test.hdfgroup.org/groups/<id>", "rel": "root"},
    {"href": "http://tall.test.hdfgroup.org/datasets/<id>/attributes", "rel": "attributes"},
    {"href": "http://tall.test.hdfgroup.org/datasets/<id>/value", "rel": "data"},
    {"href": "http://tall.test.hdfgroup.org/", "rel": "home"}

This enables clients to “explore” the api without detailed knowledge of the API.

This is the list of relations used in h5serv:

  • attributes - the attributes of the resource
  • data - the resources data (used for datasets)
  • database - the collection of all datasets in the domain
  • groupbase - the collection of all groups in the domain
  • home - the domain the resource is a member of
  • owner - the containing object of this resource (e.g. the group an attribute is a member of)
  • root - the root group of the domain the resource is a member of
  • self - this resource
  • typebase - the collection of all committed types in the domain