Nifi - SplitJson retaining all other info - json

Question

Working in Nifi, I have the following json structure in the content of a flow file:
{
"firstname": "fred",
"lastname": "jackson",
"dob": "19550607",
"children": [{
"firstname": "janet",
"lastname": "jackson",
"dob": "20020607"
},
{
"firstname": "michael",
"lastname": "jackson",
"dob": "20010201"
},
{
"firstname": "tito",
"lastname": "jackson",
"dob": "20030707"
}
]
}
I want to split this such that I would have three (3) flowfiles, each containing the top level info, but with just one child. For example one of them would look like this:
{
"firstname": "fred",
"lastname": "jackson",
"dob": "19550607",
"children": {
"firstname": "janet",
"lastname": "jackson",
"dob": "20020607"
}
}
Again, I would have three different flow files, one for each child. The output does not have to look exactly like this. The important thing is that I am able to split the struture, yet maintain the common data in each of the result flow files.
I tried using SplitJson with a JSONExpression of "$.children", which does give me the three flow files, but I loose the parent info. I could save the key/values for the common elements in attributes, split, and then add them, but the parent information can be more complex than my example (dynamic fields, etc), so I am unsure how I would do this.
Appreciate any ideas or thoughts.

Answer 1

The simplest way would be to use ForkRecord with a JSON Reader/Writer.
Set Include Parent Fields to true to retain the parent fields.
However, this may flatten the JSON in a way that you don't want - give it a try.
Alternatively, look at JoltTransformJSON which gives a lot more flexibility, but is quite complex to work out the appropriate spec. You can use https://jolt-demo.appspot.com/#inception to test your JOLT Specs.