Thing Tracker Network Specification [draft]

The json schema shown to the right shows a subset of the structure of a valid tracker document (shown in js-schema format for conciseness). The following table summarises the key aspects.

schema({
  "id" : String,
  "things" : Array.of(
      {
          "id" : String,
          "title": String,
          "*url": String,
          "*author": String,
          "*license": String,
          "*tags": Array.of(String),
          "*thumbnailURL": String,
          "*description": String
      }
  ),
  "*trackers" : Array.of(
      {
          "url": String
      }
  )
})
          

{
  "description": "An Example Thing Tracker.",
  "things":[
      {
        "id":"cdebf011-e999-4dc5-b4c2-c4163f5584a0",
        "title": "strandbeest",
        "url": "http://garyhodgson.github.com/strandbeest",
        "author": "Gary Hodgson"
      },
      {
        "id":"f8736600-ff82-4a92-a5e9-fdeeeeb259fe",
        "title": "Mechanical Movement #27",
        "url": "http://garyhodgson.github.com/githubiverse-tst",
        "author": "Gary Hodgson",
        "license": "GPL3",
        "tags": ["mechanical movement", "fun"],
        "thumbnailUrl": "https://github.com/garyhodgson/githubiverse-tst/raw/master/img/test-jig.jpg",
        "description": "An implementation of movement #27 from "501 Mechanical Movements" by Henry T. Brown.\\n\\nThis is still a work in progress."
      }
  ],
  "trackers":[
    {
      "url":"http://reprap.development-tracker.info/thingtracker"
    }
  ]
}
          

To the left is an example tracker which would validate against the above schema. It shows two things and one child-tracker.

This example can also be found in raw json, or displayed in the Thing Tracker Viewer.

To address the issue of scalability a tracker may be also be structured in a different way. A small tracker with only a handful of things would be adequately covered by a single Tracker, however even a modest number of Things would cause the size of this object to become unwieldy. The solution is to have the Tracker reference a separate JSON object for each Thing, each located in it's own resource. This is accomplished by means of the "refUrl" attribute.

To aid clients and services it is probably sensible to also provide some minimal metadata in the root tracker object, such as the title of the Thing, so they can retrieve some of the information without having to perform a request for each Thing in turn.

Example

Root Tracker

  {
    "description": "An Example Thing Tracker with referenced Things.",
    "things":[
        {
          "title": "Mechanical Movement #27",
          "refUrl": "/thing/f8736600-ff82-4a92-a5e9-fdeeeeb259fe"
        }
    ],
    "trackers":[
      {
        "url":"http://reprap.development-tracker.info/thingtracker"
      }
    ]
  }
          

Thing at url "/thing/f8736600-ff82-4a92-a5e9-fdeeeeb259fe"

  {
    "id":"f8736600-ff82-4a92-a5e9-fdeeeeb259fe",
    "title": "Mechanical Movement #27",
    "url": "http://garyhodgson.github.com/githubiverse-tst",
    "author": "Gary Hodgson",
    "license": "GPL3",
    "tags": ["mechanical movement", "fun"],
    "thumbnailUrl": "https://github.com/garyhodgson/githubiverse-tst/raw/master/img/test-jig.jpg",
    "description": "An implementation of movement #27 from "501 Mechanical Movements" by Henry T. Brown.\\n\\nThis is still a work in progress."
  }