How to send a .json file from Flow to Azure Function and return results?

I want to send a serialized .json file to a PowerShell Azure Function, prettify it, then return the file to Flow for further processing. I cannot figure out how to do this.

In Flow:

• Trigger: Button push
• Action1: Get file content from OneDrive
  • Output:

    {
      "$content-type": "application/octet-stream",
      "$content": "eyJUb3BQYXJlbnQiOns...<truncated for this post>"
    }

• Action2: Send HTTP Request
  • URI: https://test.azurewebsites.net/api/prettifyJson?code=<api key>
  • Method: POST
  • Body: body('Get_file_content') (output from Action1)

In Azure Function:

• Default PowerShell run.ps1:

using namespace System.Net

# Input bindings are passed in via param block.
param($Request, $TriggerMetadata)

# Write to the Azure Functions log stream.
Write-Host "PowerShell HTTP trigger function processed a request."

# Interact with body of the request.
$content = $Request.Query.baz
if (-not $name) {
    $name = $Request.Body.baz
}

if ($name) {
    $status = [HttpStatusCode]::OK
    $body = "Hello $name"
}
else {
    $status = [HttpStatusCode]::BadRequest
    $body = "Please pass a name on the query string or in the request body."
}

# Associate values to output bindings by calling 'Push-OutputBinding'.
Push-OutputBinding -Name Response -Value ([HttpResponseContext]@{
    StatusCode = $status
    Body = $content
})

Issues:

1. A call to the function fails with Please pass a name on the query string or in the request body. I can see why, but do not know what syntax to replace in run.ps1

2. I have no idea what syntax to use to:

   a. Receive the .json file

   b. Convert it to pretty json

   c. Repackage the .json file

   d. Send it back to Flow

Looking for guidance.