Nifi Jolt nested arrays turn into array of custom objects

Question

Am absolutely stumped trying to take nested arrays from JSON input and turn them into an array of objects with proper Keys and values using Nifi Jolt Transform.

The issue I'm reaching is that I need to manually specify the column names. They are not apparent from the JSON response.

Column names are

{
  "column_names": [
    "icao24",
    "callsign",
    "origin_country",
    "time_position",
    "last_contact",
    "long",
    "lat",
    "baro_altitude",
    "on_ground",
    "velocity",
    "true_track",
    "vertical_rate",
    "sensors",
    "geo_altitude",
    "squawk",
    "spi",
    "position_source"
  ]
}

Example input data:

{
  "time": 1675791934,
  "states": [
    [
      "a57b26",
      "N452SM  ",
      "United States",
      1675791621,
      1675791621,
      -105.1168,
      39.9103,
      null,
      true,
      0,
      90,
      null,
      null,
      null,
      null,
      false,
      0
    ],
    [
      "aa56da",
      "UAL1986 ",
      "United States",
      1675791933,
      1675791933,
      -122.1349,
      41.1152,
      10972.8,
      false,
      235.33,
      2.51,
      0,
      null,
      11049,
      null,
      false,
      0
    ]
  ]
}

Expected output:

[
  {
    "icao24": "a57b26",
    "callsign": "N452SM  ",
    "origin_country": "United States",
    "time_position": 1675791621,
    "last_contact": 1675791621,
    "long": -105.1168,
    "lat": 39.9103,
    "baro_altitude": null,
    "on_ground": true,
    "velocity": 0,
    "true_track": 90,
    "vertical_rate": null,
    "sensors": null,
    "geo_altitude": null,
    "squawk": null,
    "spi": false,
    "position_source": 0
  },
  {...}
]

The result that I'm coming up with from shift Jolt spec is...

[
  {
    "operation": "shift",
    "spec": {
      "states": {
        "*": {
          "*": "[&1]"
        }
      }
    }
  }
]

Result:

[
  [
    "a57b26",
    "N452SM  ",
    "United States",
    1675791621,
    1675791621,
    -105.1168,
    39.9103,
    null,
    true,
    0,
    90,
    null,
    null,
    null,
    null,
    false,
    0
  ],
  [
    "aa56da",
    "UAL1986 ",
    "United States",
    1675791933,
    1675791933,
    -122.1349,
    41.1152,
    10972.8,
    false,
    235.33,
    2.51,
    0,
    null,
    11049,
    null,
    false,
    0
  ]
]

I'd be able to possibly figure it out if the column names were sent in the payload, but unfortunately I need to set them manually in the transformation.

I did happen to find a helpful stack of a similar situation, but again, the solution looks like heavy duty regex and I'm just not that quite well versed in Nifi Jolt yet.

Jolt reference first element in array as target name

Answer 1

Ended up solving this on my own :

[
  {
    "operation": "default",
    "spec": {
      "temp": [
        [
          "icao24",
          "callsign",
          "origin_country",
          "time_position",
          "last_contact",
          "long",
          "lat",
          "baro_altitude",
          "on_ground",
          "velocity",
          "true_track",
          "vertical_rate",
          "sensors",
          "geo_altitude",
          "squawk",
          "spi",
          "position_source"
        ]
      ]
    }
  },
  {
    "operation": "shift",
    "spec": {
      "temp": {
        "*": "states[]"
      },
      "states": {
        "*": "states[]"
      }
    }
  },
  {
    "operation": "shift",
    "spec": {
      "states": {
        "*": {
          "*": "[&1].@(2,[0].[&])"
        }
      }
    }
  },
  {
    "operation": "shift",
    "spec": {
      "0": null,
      "*": "[]"
    }
  }
]

And this is the expected output :

[
  {
    "icao24": "a57b26",
    "callsign": "N452SM  ",
    "origin_country": "United States",
    "time_position": 1675791621,
    "last_contact": 1675791621,
    "long": -105.1168,
    "lat": 39.9103,
    "baro_altitude": null,
    "on_ground": true,
    "velocity": 0,
    "true_track": 90,
    "vertical_rate": null,
    "sensors": null,
    "geo_altitude": null,
    "squawk": null,
    "spi": false,
    "position_source": 0
  },
  {
    "icao24": "aa56da",
    "callsign": "UAL1986 ",
    "origin_country": "United States",
    "time_position": 1675791933,
    "last_contact": 1675791933,
    "long": -122.1349,
    "lat": 41.1152,
    "baro_altitude": 10972.8,
    "on_ground": false,
    "velocity": 235.33,
    "true_track": 2.51,
    "vertical_rate": 0,
    "sensors": null,
    "geo_altitude": 11049,
    "squawk": null,
    "spi": false,
    "position_source": 0
  }
]