Refactor some synchronous API calls to async

[oyo]

Description

Currently some longer running backend calls are implemented as synchronous calls in an unsafe way. More appropriate would be an asynchronous mechanism.

Acceptance Criteria

• calls have been converted to async and use same semantic of separate invocations for create and read requests

Additional Information

Proposed async logic (Example: user)

Create:

POST /api/user
{
  "name": "myuser",
  "email": "[email protected]"
}

{
  "processId": "789",
  "status": "PENDING",
  "requestDate": 1732715777589
  "requestData": {
    "name": "myuser",
    "email": "[email protected]"
  }
}

Read:

GET /api/user/789

{
  "processId": "789",
  "status": "PENDING",
  "requestDate": 1732715777589,
  "requestData": {
    "name": "myuser",
    "email": "[email protected]"
  }
}

GET /api/user/123

{
  "processId": "123",
  "status": "SUCCESS",
  "requestDate": 1732715770000,
  "requestData": {
    "name": "someuser",
    "email": "[email protected]"
  },
  "resolveDate": 1732715771234
  "resolveData": {
    "id": "f81d4fae-7dec-11d0-a765-00a0c91e6bf6",
    "name": "someuser",
    "email": "[email protected]"
  }
}

List:

GET /api/users

[
  {
    "processId": "789",
    "status": "PENDING",
    "requestDate": 1732715777589,
    "requestData": {
      "name": "myuser",
      "email": "[email protected]"
    }
  },
  {
    "processId": "123",
    "status": "SUCCESS",
    "requestDate": 1732715770000,
    "requestData": {
      "name": "someuser",
      "email": "[email protected]"
    },
    "resolveDate": 1732715771234
    "resolveData": {
      "id": "f81d4fae-7dec-11d0-a765-00a0c91e6bf6",
      "name": "someuser",
      "email": "[email protected]"
    }
  },
  {
    "processId": "912",
    "status": "FAILURE",
    "requestDate": 1732715000000,
    "requestData": {
      "name": "thisuser",
      "email": "[email protected]"
    },
    "resolveDate": 1732715009999,
    "resolveData": {
      "code": "ITEM_CREATE_TIMEOUT",
      "message": "No response from keycloak server",
      "details": { ... }
    }
  }
]