Direct node

A direct node in a HIM configuration file defines a tree that the server managing this forest have a local and complete copy of. This means that the server can efficiently parse the tree to e. g. verify that a client request for information points to an existing node in the tree.

Nodes of the type direct must have the following mandatory metadata:

  • Name
  • Type
  • Domain
  • Version
  • Local
  • Description

For more information, see the Common Rule Set: Mandatory Metadata.

Besides the mandatory metadata mentioned above, the following optional metadata may be used

  • Public
  • Comment

For more information, please see the Common Rule Set: Optional Metadata.

This node type must have a node of type branch as parent, and must not have any children.

Name

The name of this node must be the same as that of the root node of the tree it is representing, and it must be unique in the forest described in this file. This makes it possible to change the root node name of a “standard” tree, which then enables that multiple instances of the same standard tree can be present in the same forest. A scenario where this may happen is when a truck has more than one trailer that each is represented by the same standard tree. The trailers can then be distinguished by having different root node names.

Domain

The domain metadata is what defines the domain and information type that the tree represents. A domain name dot delimited segment names:

  • The first segment (the left-most) represents a “top domain”.
    • Examples of top domains can be Automotive, RoadInfrastructure, Aviation.
  • Following segments, except the last, are sub domains.
    • Examples of sub domains can be Car, Truck, Trailer, ChargingStation.
    • The number of sub domains is not fixed, but it is recomended to stay below five.
    • Each additional sub domain should be a subset of the previos domain.
  • The last segment (the right-most) represents the information type.

Version

The version shall be identical to the version of the tree where it shall be mandatory. Versioning shall be based on the Semantic versioning principles.

Local

The local metadata shall be a file URL or similar that points to a local file that contains the tree. The local metadta shall not be supplied to a client requesting the configuration file.

Public

The public metadata shall, if available, be a URL to a public copy of the tree. It may be used to provision a server with a copy of the tree, but also by a client to obtin a copy instead of e. g. requesting the server to provision a copy.

An example of the specification of a direct node is given below.

VehicleData:
  type: direct
  domain: Vehicle.Car.ResourceData
  version: X.Y.Z
  local: file://<full-path-name>
  public: https://himrepo.oem.com?intance=Vehicle.Car.ResourceData.X.Y.Z
  description:  ….