The versatile assets in IoT applications can be managed as Things.

Thing

Things are very generic entities and are mostly used as a “handle” for multiple features belonging to this Thing.

Examples:

  • Physical Device: a lawn mower, a sensor, a vehicle, a lamp.
  • Virtual Device: a room in a house, a virtual power plant spanning multiple power plants, the weather information for a specific location collected by various sensors.
  • Transactional entity: a tour of a vehicle (from start until stop), a series of measurements of a machine.
  • Master data entity: a supplier of devices or a service provider for devices, an entity representing a city/region.
  • Anything else - if it can be modeled and managed appropriately by the supported concepts/capabilities.

Thing ID

Unique identifier of a Thing. For choosing custom Thing IDs when creating a Thing, the rules for namespaced IDs apply.

Access control

A Thing in API version 1 contains an inline ACL defining which authenticated parties may READ, WRITE and ADMINISTRATE the Thing.

A Thing in API version 2 does no longer contain the ACL. Instead it contains a link to a Policy in form of a policyId. This Policy defines which authenticated subjects may READ and WRITE the Thing or even parts of it (hierarchically specified).

Attributes

Attributes describe the Thing in more detail and can be of any type. Attributes can also be used to find Things. Attributes are typically used to model rather static properties at the Thing level. Static means that the values do not change as frequently as property values of Features.

Features

A Thing may contain an arbitrary amount of Features.

Thing and Feature
One Thing can have many Features

Model specification

API version 1

API version 2

Example (API version 1)

{
  "thingId": "the.namespace:theId",
  "acl": {
    "subject-id": {
      "READ": true,
      "WRITE": true,
      "ADMINISTRATE": true
    }
  },
  "attributes": {
      "someAttr": 32,
      "manufacturer": "ACME corp"
  },
  "features": {
      "heating-no1": {
          "properties": {
              "connected": true,
              "complexProperty": {
                  "street": "my street",
                  "house no": 42
              }
          }
      },
      "switchable": {
          "properties": {
              "on": true,
              "lastToggled": "2017-11-15T18:21Z"
          }
      }
  }
}
Tags: model