URL Parameters should be communicated to clients via URL templates

[ssfrr]

for instance, when requesting sensor data the user can provide a start and end timestamp, but currently the server does not tell the client which parameters are available.

[kkleidal]

What do you think about this approach: including a list of possible parameters in the response alongside the href. I played around with the idea on this branch:

https://github.com/kkleidal/chain-api/commit/dbfae46a913325baa16dc1283e31eeb744263356

Example output (I didn't actually define any params for the resource types shown):

{
  "building": "",
  "room": "",
  "floor": "",
  "description": "",
  "_links": {
    "ch:site": {
      "href": "http://127.0.0.1:8080/sites/1",
      "params": [],
      "title": "MIT Media Lab"
    },
    "curies": [
      {
        "href": "http://chain-api.media.mit.edu/rels/{rel}",
        "name": "ch",
        "templated": true
      }
    ],
    "self": {
      "href": "http://127.0.0.1:8080/devices/1",
      "params": []
    },
    "ch:websocketStream": {
      "href": "ws://127.0.0.1:8080/ws/device-1",
      "title": "Websocket Stream"
    },
    "ch:sensors": {
      "href": "http://127.0.0.1:8080/sensors/?device_id=1",
      "params": [],
      "title": "Sensors"
    },
    "editForm": {
      "href": "http://127.0.0.1:8080/devices/1/edit",
      "title": "Edit Device"
    }
  },
  "name": "example"
}