public/Get-VSAAgent.ps1

function Get-VSAAgent
{
    <#
    .Synopsis
       Returns all VSA agents or specific one
    .DESCRIPTION
       Returns all VSA agents or specific one if agent id supplie.
       Takes either persistent or non-persistent connection information.
    .PARAMETER VSAConnection
        Specifies existing non-persistent VSAConnection.
    .PARAMETER URISuffix
        Specifies URI suffix if it differs from the default.
    .PARAMETER AgentId
        Specifies id of agent machine.
    .PARAMETER Filter
        Specifies REST API Filter.
    .PARAMETER Paging
        Specifies REST API Paging.
    .PARAMETER Sort
        Specifies REST API Sorting.
    .EXAMPLE
       Get-VSAAgent
    .EXAMPLE
       Get-VSAAgent -AgentId 3423232424
    .EXAMPLE
       Get-VSAAgent -VSAConnection $connection
    .INPUTS
       Accepts piped non-persistent VSAConnection
    .OUTPUTS
       Array of custom objects that represent existing VSA agents or specific agent
    #>


    [CmdletBinding()]
    param ( 
        [parameter(Mandatory = $true, 
            ValueFromPipelineByPropertyName = $true,
            ParameterSetName = 'NonPersistent')]
        [VSAConnection] $VSAConnection,
        [parameter(Mandatory=$false,
            ValueFromPipelineByPropertyName=$true,
            ParameterSetName = 'NonPersistent')]
        [parameter(Mandatory=$false,
            ValueFromPipelineByPropertyName=$true,
            ParameterSetName = 'Persistent')]
        [ValidateNotNullOrEmpty()] 
        [string] $URISuffix = 'api/v1.0/assetmgmt/agents',
        [Parameter(Mandatory = $false)]
        [ValidateScript({
            if( $_ -notmatch "^\d+$" ) {
                throw "Non-numeric Id"
            }
            return $true
        })]
        [string] $AgentId,
        [Parameter(ParameterSetName = 'Persistent', Mandatory = $false)]
        [Parameter(ParameterSetName = 'NonPersistent', Mandatory = $false)]
        [ValidateNotNullOrEmpty()] 
        [string] $Filter,
        [Parameter(ParameterSetName = 'Persistent', Mandatory = $false)]
        [Parameter(ParameterSetName = 'NonPersistent', Mandatory = $false)]
        [ValidateNotNullOrEmpty()] 
        [string] $Paging,
        [Parameter(ParameterSetName = 'Persistent', Mandatory = $false)]
        [Parameter(ParameterSetName = 'NonPersistent', Mandatory = $false)]
        [ValidateNotNullOrEmpty()] 
        [string] $Sort
    )


    if( -not [string]::IsNullOrWhiteSpace( $AgentId) ) {
        $URISuffix += "/$AgentId"
    }

    [hashtable]$Params =@{
        URISuffix = $URISuffix
    }

    if($VSAConnection) {$Params.Add('VSAConnection', $VSAConnection)}
    if($Filter)        {$Params.Add('Filter', $Filter)}
    if($Paging)        {$Params.Add('Paging', $Paging)}
    if($Sort)          {$Params.Add('Sort', $Sort)}

    return Get-VSAItems @Params
}

Export-ModuleMember -Function Get-VSAAgent