Handling NULL in Parse JSON

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Posted on by ChrisCC

I have an API which has the following characteristics:

Schema:

{
"type": "array",
"items": {
    "type": "object",
    "properties": {
      "StartDate": {
        "type": "string"
      },
      "EndDate: {
        "type": "string"
      },

}

}
}

**************************

Example failure payload:

{
"StartDate": "6/15/2017",
"EndDate": null,
}

Note that this works if both StartDate and EndDate are not null

The Parse JSON step with the above schema returns "Error - Expected String, received null"

Replacing the EndDate data type "string" with "any" causes it to be unreadable in following steps (as though it was never parsed) and changing it to "data" causes an internal server error.

Is there any way to create a schema which allows null values in the "Parse JSON" step?

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v-micsh-msft Microsoft Employee on at

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Hi @ChrisCC,

I don't think there would be schema which could allow Null value.

Please consider replace the Null value with some string, or add a condition to check if the value is Null with the empty funciton.

Or you may consider submit this as an idea, to suggest add the Null support under parse JSON action.

Regards,

Michael

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JoeGasper 85 on at

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This seems to be working:

"heat_index_f": {
"type": ["number","null"]
},
"heat_index_c": {
"type": ["number","null"]
},

https://powerusers.microsoft.com/t5/Building-Flows/parse-JSON-Ignoring-null-value-s-when-parsing-JSON-payload/m-p/31999/highlight/true#M2937

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TobyJH 4 on at

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Works for any data type:
"id_numeric": {
"type": [
"integer",
"null"
]
},
"department_head_name": {
"type": [
"string",
"null"
]
},

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SwJ23 85 on at

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I used this suggestion for a few flows and it works great, but it prevents me from using Dynamic content from any Parse JSON action whose schema I modify to accept null values.

After a great deal of dinking around I stumbled across removing the "type": "string" field altogether, leaving in its place a null object. Other than needing to be very careful with where you put the typeless dynamic content, I haven't encountered a serious drawback yet; but that doesn't mean there isn't one!

Your schema:

"heat_index_f": {},
"heat_index_c": {}

OP Schema:

{
"type": "array",
"items": {
    "type": "object",
    "properties": {
      "StartDate": {},
      "EndDate: {},
}
}
}

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testasdfasfsafa 309 on at

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I can't believe after all these years that Microsoft still hasn't fix this simple issue

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MichelH 401 on at

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When I add a second option to the JSON schema, either null or string, power apps simply refuses the refresh of the flow stating:

Unable to add flow
There was a problem adding your service. Please try again later.

The flow input and output schema cannot be represented in WADL.
code: FlowWadlConversionNotSupported

The JSON schema seems valid.
"Maintenance": { "type": ["number","string"] }, "Maintenance": { "type": ["number","null"] },

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testasdfasfsafa 309 on at

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There was a roadmap item for power automate to better handle null values, I can't find it anymore 😞
It's a real pain. Don't why Microsoft doesn't improve the handling of null values.

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Heartholme 1,278 Super User 2024 Season 1 on at

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@testasdfasfsafa @MichelH

This should help you: https://powerpostal365.com/2023/10/04/how-to-handle-null-data-when-passing-json-objects-from-flow-to-powerapps/

It works in any case, while the other solution might not always work based on your data/flow.

✔ Marking my post as a solution not only confirms that your question has been answered, but also helps others find solutions to similar problems.
By doing so, you'll be making a valuable contribution to the community.

Best Regards
Heartholme

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Hans Smeets 39 on at

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This does not seem to work (anymore). The flow accepts the scheme when saving, but it fails when running

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MarkMillian on at

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I got it to work today so it should still be possible. The field that I changed did disapear for me in the beginning but I was able to hardcode the field and make it work.

{
"type": "array",
"items": {
"type": "object",
"properties": {
"Checked": {
"type": [
"boolean",
"null"
]
},
"Name": {
"type": "string"
}
},
"required": [
"Checked",
"Name"
]
}
}

After the change I was only able to select "name", "Item", or "Body" from my parse json. I just copied the "name" value and wrote "checked" like so:
items('Apply_to_each')['Name'] ---> items('Apply_to_each')['Checked']

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