PowerShell SharePoint API with Invoke-RestMethod Return String

With PowerShell, we can use the invoke-RestMethod cmdlet to make Restful API calls to get JSON data. When using the SharePoint Restful APIs, the cmdlet returns the JSON data in string format which is not the intended result. To handle this problem, we can convert the string to a JSON object, so we can work with the structured data instead of a string by using the following script:

Invoke-RestMethod Docs

We should note that when we try to convert a SharePoint JSON string using the ConvertFrom-Json cmdlet, we get an error that the string is not a valid JSON because there are duplicate attributes (Id, ID) which are returned by default on the payload.  To address this, we can replace one of the attributes while the JSON is still in a string type.  We can then convert the string again and all should work.

Please keep in mind that this is a behavior that is applicable to PowerShell. If you use the JavaScript parser, this error is not raised.

I hope this is able to help you consume SharePoint JSON data using PowerShell.

Originally published by ozkary.com