How to handle "null" value in JSON when developing the Custom Connector of the Power Platform and Automate?

[TakeshiOsanai]

I'm developing the Custom Connector and the Automate on the Power Platform.

Let's say that:

• The Automate flow receive JSON via the custom connector

• The JSON response data has over hundreds of properties

• The JSON may have "null" value on some of properties, and they cannot be predictable what property have the null value

• According to that reason, I have to handle the null value with the Custom Connector

To avoid error, what kind of method can I have with developing the connector?

FYI: I found the Microsoft's document, but the below way cannot be used because of the reason I wrote above.

https://support.microsoft.com/en-us/topic/getting-errors-with-null-fields-d0a36825-72eb-bd78-dcc0-26...

[manuelstgomes]

Hi @TakeshiOsanai 

There's another way to enable null values. In the JSON definition you should have something like this:

{
    "type": "object",
    "properties": {
        "days": {
            "type": "integer"
        }
    }
}

In the example above we're indicating that "days" is a integer and only an integer. If it's something else it will fail. Since null is not an integer you get an error every time there's a null value.

To fix it you need to define that the value can receive 2 types. The actual type (string, integer, etc) and null. So you can do something like this:

{
    "type": "object",
    "properties": {
        "days": {
            "type": [
                "integer",
                "null"
            ]
        }
    }
}

Do this for all the types that you know that a null value is possible. Don't forget, in the Flow, to deal with the null values so not to save invalid values.

Now the type can be 2 things and not only one.

Does this make sense?

Can you please check if and let me know if you have any questions?

Cheers
Manuel

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[TakeshiOsanai]

Hi @manuelstgomes.

Thank you for your quick response, and sorry for my late reply.

Let me ask you more in detail.

Is this solution the official way to solve the null problem and written in Microsoft's documentation?

Or is this an unofficial workaround?

The reasons of my asking are:

* I want to make the connector  certified by Microsoft and reveal it to the connector's page
https://flow.microsoft.com/en-US/connectors/
 

* I am wondering that Microsoft suddenly change the specification of the Automate and this workaround will be invalitated or not.

This may be the needless worry, but want to clear.

Thanks in advance!

[manuelstgomes]

HI @TakeshiOsanai 

Great question. This is how JSON schemas work so it's not a workaround.

https://json-schema.org/understanding-json-schema/reference/null.html

Good luck with the submission.

Cheers
Manuel

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[rvroman]

Manuel - 

Can you describe/show how this would be defined in the Custom Connector? When trying to implement your solution I get an error message about null not being a supported type in the Swagger Editor:

should be equal to one of the allowed values allowedValues: array, boolean, integer, number, object, string

[SDRobert]

I'd love to know the answer for this myself.

Also looking to make an actual custom connector the has to handle possible null values in response body from the GET.

Be nice to at least find a "this is not supported" message but cannot find that spelled out yet either.