Standardise API calls

[jpomfret]

We should standardise how the APIs are called from each function.

Some use a wrapper function

        $Datamarts = Invoke-FabricAPIRequest `
            -BaseURI $apiEndpointURI `
            -Headers $FabricConfig.FabricHeaders `
            -Method Get

Some just call Invoke-RestMethod directly

[NowinskiK]

Please leave it with me. Let's finalise and close the Sampler branch first.

[SQLDBAWithABeard]

Issue not resolved.
Happy for it to be assigned to you Kamil

[NowinskiK]

This issue is closely related to #18, hence I marked it as a duplicate and closed.

[jpomfret]

Linked as a sub issue to #18

Standardising the auth felt like a much bigger project than just updating all the API calls to use the wrapper - but I'm still getting to know the codebase

[NowinskiK]

Thanks @jpomfret for making this sub-task, good idea. It's a bit bigger but not very much. I have an Excel - output of the discovery I did 2 weeks ago. Happy to share with you.

[jpomfret]

@NowinskiK - do we agree that we'll standardise to using the Invoke-FabricAPIRequest function for calls to the API?

I think it makes sense but just wanted to confirm

[NowinskiK]

@jpomfret I reviewed most of the functions and the result of the discovery is as follows:

API Request function	Used	Source
Invoke-RestMethod	159	PowerShell
Invoke-WebRequest	16	PowerShell
Invoke-FabricAPIRequest (uses B)	57	Wrapper. FabricTools
Invoke-PowerBIRestMethod	3	Wrapper. MicrosoftPowerBIMgmt.Profile

I also believe it makes sense to write a wrapper like Invoke-FabricAPIRequest.
Here, I will introduce a new function Invoke-FabricRestMethod,
which will call Invoke-AzRestMethod rather than Invoke-RestMethod or Invoke-WebRequest.
This should also resolve the problem of the breaking change introduced by Az.Accounts v.5.0 (Get-AzAccessToken).

Please take a look below and let me know if you have any concerns - I'm happy to talk:

[jpomfret]

Yeah makes sense to me, seems more secure than passing plain text token too.

The breaking change in Az.Accounts 5.0 is a weird one for me - in the lead up it was recommended you could add -SecureString:$false so things remained working after this change - but that still results in a secure string being returned for the token.

[NowinskiK]

I spent some time yesterday on this, and it doesn't look easy to accommodate a new, more secure approach.
So probably "Invoke-AzRestMethod" will wait for a better moment and be a separate, bigger issue.