API - Sample Add Attachment via Powershell?

Adding attachments to Incidents isn't properly documented in SWSD's API, however it should be possible. See my response on a similar question here:
https://thwack.solarwinds.com/product-forums/solarwinds-service-desk-swsd/f/forum/91726/can-i-attach-files-to-samange-api-call

As for the PowerShell bit, I'm not much of a PowerShell user, but this guide seems to give a pretty solid step-by-step of how to use PowerShell to make requests against an API with basic auth. https://adamtheautomator.com/invoke-restmethod/

Thanks Mitch, 

I am able to do everything I want with the API except posting an attachment.

I looked at your comments and google hunted some other examples of Invoke-RestMethod posting.  Unfortunately none of them seem to work for SWSD API.  So I'm clearly missing a key piece of the puzzle. 

I did ask SWSD support for help but their first response wasn't very helpful.  

Update: As noted Powershell 7 is required for -form support. 

I was able to get things to work.  Posting here my notes to help any future people searching for clues.   

Adding to the ticket.

$file = @{
    "file[attachable_type]" = "Incident"
    "file[attachable_id]" = "123456"
    "file[attachment]" = (get-item -path "C:\temp\Test.txt")
}

$uri = "https://api.samanage.com/attachments.json"

Invoke-RestMethod -Uri $uri -form $file -ContentType 'multipart/form-data' -ResponseHeadersVariable ResponseHeader -Method Post -WebSession $session

Adding to a comment in the ticket.

$file = @{
    "file[attachable_type]" = "Comment"
    "file[attachable_id]" = "123456"
    "file[attachment]" = (get-item -path "C:\temp\Test.txt")
}

$uri = "https://api.samanage.com/attachments.json"

Invoke-RestMethod -Uri $uri -form $file -ContentType 'multipart/form-data' -ResponseHeadersVariable ResponseHeader -Method Post -WebSession $session

Also found that when using the curl example on Windows you need to use double quotes not the single quote as shown in the API doc. 

Note: You must be using PowerShell 7.x+ for this as the Invoke-RestMethod from previous versions does not support the -Form parameter.

Yes that is correct.  Thanks for noticing that.