Question: Should it be possible to query an action by name only?

[benfrancis]

Continuing the discussion from #43 and #91 with a more specific question...

Should it be possible to query an action by name only, without an actionID? If so, should the response contain an array of ActionStatus objects for all ongoing and recently completed instances of that action (similar to queryallactions), or just one ActionStatus object for the the latest instance (for some definition of "latest")?

The definition of the queryaction operation in the Thing Description specification is a bit ambiguous on this point:

"Identifies the querying operation on Action Affordances to get the status of the corresponding action."

[benfrancis]

My personal view is that the simplest solution is for the queryaction operation to only allow querying a single instance of an action by its actionID, which is consistent with the current HTTP Basic Profile.

However, if we were going to allow querying an action only by name then I would suggest the response should contain a statuses member set to an array of ActionStatus objects representing all ongoing and recently completed instances of the action, similar to the queryallactions operation but filtered for a single action name.

Request:

{
  "thingID": "https://mythingserver.com/things/mylamp1",
  "messageID": "f9dc3a42-188e-47f3-a0ed-cd3c3fb93207",
  "messageType": "request",
  "operation": "queryaction",
  "name": "fade",
  "correlationID": "f6293376-5ddb-43ef-ba21-aa34ceb48a58"
}

Response:

{
  "thingID": "https://mythingserver.com/things/mylamp1",
  "messageID": "84df00ce-dbe0-41fa-acf5-cdadcefd414e",
  "messageType": "response",
  "operation": "queryaction",
  "name": "fade",
  "statuses": [
      {
        "actionID": "d95100b9-decc-4b11-81b8-81870597ebeb",
        "timeRequested": "2025-09-09T17:38:13.631Z",
        "status": "pending"
      },
      {
        "actionID": "66546f79-84bd-4ac9-b728-bb4168a17330",
        "timeRequested": "2025-09-09T17:36:00.363Z",
        "status": "running"
      },
      {
        "actionID": "c1e116a4-7832-4338-a72c-330c871b991a",
        "status": "completed",
        "timeRequested": "2025-09-09T17:34:50.361Z",
        "timeEnded": "2025-09-09T17:34:55.361Z",
        "output": true,
      }
    ]
  "timestamp": "2025-09-09T17:34:51.531Z",
  "correlationID": "f6293376-5ddb-43ef-ba21-aa34ceb48a58"
}

My biggest concern with this approach is that it overloads a single operation with what are essentially two separate operations - queryaction and queryactioninstance - with two different request formats and two different response formats.

The other format being one where an actionID is specified:

Request:

{
  "thingID": "https://mythingserver.com/things/mylamp1",
  "messageID": "f9dc3a42-188e-47f3-a0ed-cd3c3fb93207",
  "messageType": "request",
  "operation": "queryaction",
  "actionID": "d95100b9-decc-4b11-81b8-81870597ebeb",
  "correlationID": "f6293376-5ddb-43ef-ba21-aa34ceb48a58"
}

Response:

{
  "thingID": "https://mythingserver.com/things/mylamp1",
  "messageID": "84df00ce-dbe0-41fa-acf5-cdadcefd414e",
  "messageType": "response",
  "operation": "queryaction",
  "name": "fade",
  "status": {
    "actionID": "d95100b9-decc-4b11-81b8-81870597ebeb",
    "state": "pending",
    "timeRequested": "2025-09-09T17:34:50.361Z",
  },
  "timestamp": "2025-09-09T17:34:51.531Z",
  "correlationID": "f6293376-5ddb-43ef-ba21-aa34ceb48a58"
}