JQ：如何使用jq挑选的数据创建JSON object？

Question

I have a complex JSON file that contains hundreds of "attributes" with their types identified by "objectTypeAttributeId".

I know that objectTypeAttributeId=328 means tickedid, objectTypeAttributeId=329 contains array of hostnames etc..

There is simplified version of the file:

{
  "objectEntries": [
    {
      "attributes": [
        {
          "id": 279792,
          "objectTypeAttributeId": 328,
          "objectAttributeValues": [
            {
              "displayValue": "ITSM-24210"
            }
          ]
        },
        {
          "id": 279795,
          "objectTypeAttributeId": 329,
          "objectAttributeValues": [
            {
              "displayValue": "testhost1"
            },
            {
              "displayValue": "testhost2"
            }
          ]
        },
        {
          "id": 279793,
          "objectTypeAttributeId": 330,
          "objectAttributeValues": [
            {
              "displayValue": "28.02.2020 11:45"
            }
          ]
        }
      ]
    }
  ]
}

I need to create output JSON using particular values picked out (according to the "objectTypeAttributeId" value) of input JSON in format like this:

{
    "tickets": [
        {
            "ticketid": "ITSM-24210",
            "hostnames": ["testhost1", "testhost2"],
            "date": "28.02.2020 11:45"
        }
    ]
}

I am new in jq, in the XSLT it is solvable using static template with placeholders for picked values.

I have tried this approach, there is my jq filter:

.objectEntries[].attributes[] |
  {ticketid: select(.objectTypeAttributeId == 328) | .objectAttributeValues[0].displayValue},
  {hostnames: select(.objectTypeAttributeId == 329) | [.objectAttributeValues[].displayValue]},
  {date: select(.objectTypeAttributeId == 330) | .objectAttributeValues[0].displayValue}

but the result of this approach is:

{
  "ticketid": "ITSM-24210"
}
{
  "hostnames": [
    "testhost1",
    "testhost2"
  ]
}
{
  "date": "28.02.2020 11:45"
}

And all my subsequent tries to format output better ends in broken jq filter or filter that does not return anything.

Please any ideas how to solve this problem?

Answer 1

Assuming a ticket is to be generated for each object entry:

{tickets: [
  .objectEntries[]
  | [.attributes[]
    | [.objectTypeAttributeId,
      (.objectAttributeValues | map(.displayValue))] as [$id, $val]
    |   if $id == 328 then {ticketId:  $val[0]}
      elif $id == 329 then {hostnames: $val}
      elif $id == 330 then {date:      $val[0]}
      else empty end
  ] | add
]}

^{Online demo}

Answer 2

Here we go, it's not pretty, there may be a better solution but it works: https://jqplay.org/s/sxussfa2Vj

.objectEntries | {tickets: map(.attributes | 
{ticketID: (reduce .[] as $r (null;  if $r.objectTypeAttributeId == 328 
then $r.objectAttributeValues[0].value else . end)),
date: (reduce .[] as $r (null;  if $r.objectTypeAttributeId == 330
then $r.objectAttributeValues[0].value else . end)), 
hostnames: (reduce .[] as $r ([];  if $r.objectTypeAttributeId == 329 
then $r.objectAttributeValues | map(.value) else . end))})}

There's a lot of unpacking and repacking going on here that sort of distracts from the core. You have an array of tickets (aka entries), and over those we map. The various properties we have to grab from different entries of an array, which is done using reduce. Reduce goes through the array of objects and picks out the right one and keeps track of the value.

Maybe there's a nice way, but this works already, so you can play with it further, trying to simplify.

Your original solution almost works, you did a good job there, just needed a map:

.objectEntries[].attributes | 
{ticketid: . | map(select(.objectTypeAttributeId == 328))[0] | 
.objectAttributeValues[0].displayValue, 
date: . | map(select(.objectTypeAttributeId == 330))[0] |
.objectAttributeValues[0].displayValue, 
hostnames: . | map(select(.objectTypeAttributeId == 329))[0] | 
[.objectAttributeValues[].displayValue]}

Try it out, it even works with multiple tickets;) https://jqplay.org/s/ydoCgv9vsI