Retrieve NetScaler Named Connection information

function Get-NSNamedConnectionInfo {

<#
.SYNOPSIS
  Retrieve NetScaler Connection information.
.DESCRIPTION
  Retrieve NetScaler Connection information, using the Invoke-RestMethod cmdlet for the REST API calls.
.NOTES
  Version:        0.3
  Author:         Esther Barthel, MSc
  Creation Date:  2018-05-20
  Updated:        2018-06-23
                  Adjusted params to work with the args[x] limitations of the SBA
  Updated:        2018-07-01
                  Added sorting and filtering to exclude internal services
  Purpose:        SBA, created for ControlUp NetScaler Monitoring
  Based upon:     https://support.citrix.com/article/CTX126853

  Copyright (c) cognition IT. All rights reserved.
#>
[CmdletBinding()]
Param(
        # Declaring the input parameters, provided for the SBA
        [Parameter(Position=0, Mandatory=$true, ValueFromPipeline=$true)]
        [string]
        $NSIP,

        [Parameter(Position=1, Mandatory=$false)]
        [string]
        $LBvServerName,

        [Parameter(Position=2, Mandatory=$true, ValueFromPipeline=$true)]
        [string]
        $NSUserName,
      
        [Parameter(Position=3, Mandatory=$true, ValueFromPipeline=$true)]
        [string]
        $NSUserPW
 )    

#region NITRO settings
    # NITRO Constants
    $ContentType = "application/json"
#endregion NITRO settings

# Ensure Debug information is shown, without the confirmation question after each Write-Debug
If ($PSBoundParameters['Debug']) {$DebugPreference = 'Continue'}

Write-Output ""
Write-Output "----------------------------------------------------------------- "
Write-Output "| Retrieving NS connectiontable information from the NetScaler: | "
Write-Output "----------------------------------------------------------------- "
Write-Output ""

# ----------------------------------------
# | Method #1: Using the SessionVariable |
# ----------------------------------------
#region Start NetScaler NITRO Session
    #Force PowerShell to bypass the CRL check for certificates and SSL connections
        Write-Verbose "Forcing PowerShell to trust all certificates (including the self-signed netScaler certificate)"
        # source: https://blogs.technet.microsoft.com/bshukla/2010/04/12/ignoring-ssl-trust-in-powershell-system-net-webclient/ 
        [System.Net.ServicePointManager]::ServerCertificateValidationCallback = {$true}

    #Connect to NetScaler VPX/MPX
    $Login = ConvertTo-Json @{"login" = @{"username"=$NSUserName;"password"=$NSUserPW}}
    try
    {
        $loginresponse = Invoke-RestMethod -Uri "https://$NSIP/nitro/v1/config/login" -Body $Login -Method POST -SessionVariable NetScalerSession -ContentType $ContentType -Verbose:$VerbosePreference -ErrorAction SilentlyContinue
    }
    Catch [System.Net.WebException]
    {
        Write-Error ("A [" + $_.Exception.GetType().FullName + "] ERROR occurred. " + $_.Exception.Message)
        Break
    }
    Catch [System.Management.Automation.ParameterBindingException]
    {
        Write-Error ("A parameter binding ERROR occurred. Please provide the correct NetScaler IP-address. " + $_.Exception.Message)
        Break
    }
    Catch
    {
        Write-Error ("A [" + $_.Exception.GetType().FullName + "] ERROR occurred. " + $_.Exception.Message)
#        echo $_.Exception | Format-List -Force
        Break
    }
    Finally
    {
        If ($loginresponse.errorcode -eq 0)
        {
            Write-Verbose "REST API call to login to NS: successful"
        }
    }
#endregion Start NetScaler NITRO Session


# --------------------------
# | Connection information |
# --------------------------
#region Get NS Connection table information
    # Base URL 
    $strURI = "https://$NSIP/nitro/v1/config/nsconnectiontable"

    # Specify the required full URL, including filters and arguments
    $strArgs = ""
    If ($LBvServerName)
    {
        # Add vServer name to URI - show ns connectiontable  "CONNECTION.LB_VSERVER.NAME.EQ(\"Web-VServer\")"
        Write-Verbose ("Added the vServer name """ + $LBvServerName + """ to the URI")
        $strArgs = ("?args=filterexpression:" + [System.Web.HttpUtility]::UrlEncode("CONNECTION.LB_VSERVER.NAME.EQ(""" + $LBvServerName + """)"))
    }

    If ($strArgs.Length -gt 0)
    {
        $strURI = $strURI + $strArgs + ",detail:FULL"
    }
    Else
    {
        $strURI = $strURI + "?args=detail:FULL"
    }

    # Method #1: Making the REST API call to the NetScaler
    try
    {
        # start with clean response variable
        $response = $null
        $response = Invoke-RestMethod -Method Get -Uri $strURI -ContentType $ContentType -WebSession $NetScalerSession -Verbose:$VerbosePreference -ErrorAction SilentlyContinue
    }
    catch
    {
        Write-Error ("An error (" + $_.Exception.GetType().FullName + ") occurred, with message: " + $_.Exception.Message)
        If ($DebugPreference -eq "Continue")
        {
            Write-Debug "Error full details: "
            echo $_.Exception | Format-List -Force
        }
    }
    Finally
    {
        If ($response.errorcode -eq 0)
        {
            Write-Verbose "REST API call to retrieve information: successful"
            If ($response.nsconnectiontable)
            {
                $FilterExpression = ($response.nsconnectiontable | Select-Object filterexpression -Unique).filterexpression
                Write-Host "Filter Expression: " -ForegroundColor Yellow -NoNewline
                Write-Host $FilterExpression

                #$response.nsconnectiontable | Format-List
                #$response.nsconnectiontable | Select-Object sourceip, sourceport, destip, destport, svctype, idletime, state, entityname, httprequest | Format-Table -AutoSize
                $response.nsconnectiontable | Select-Object @{N='      Source IP'; E={"{0,15}" -F $_.sourceip}}, 
                                                    @{N='S Port'; E={$_.sourceport}}, 
                                                    @{N=' Destination IP'; E={"{0,15}" -F $_.destip}}, 
                                                    @{N='D Port'; E={$_.destport}}, 
                                                    @{N='Svc type'; E={$_.svctype}}, 
                                                    @{N='Idle time'; E={$_.idletime}}, 
                                                    @{N='       State'; E={"{0,12}" -F $_.state}}, 
                                                    @{N='Entity name'; E={$_.entityname}}, 
                                                    @{N='HTTP request'; E={$_.httprequest}} | Sort-Object '      Source IP','Svc type'| Where-Object {$_.'entity name' -ne 'INTERNAL'} | Format-Table -AutoSize
            }
            Else
            {
                Write-Warning "No connection information was found"
                Write-Output ""
            }
        }
        Else
        {
            If ($response -eq $null)
            {
                Write-Warning "No information was returned by NITRO"
            }
            Else
            {
                Write-Warning "NITRO returned an error."
                Write-Debug ("code: """ + $response.errorcode + """, message """ + $response.message + """")
            }
        }
    }
#endregion


#region End NetScaler NITRO Session
    #Disconnect from the NetScaler VPX
    $LogOut = @{"logout" = @{}} | ConvertTo-Json
    $dummy = Invoke-RestMethod -Uri "https://$NSIP/nitro/v1/config/logout" -Body $LogOut -Method POST -ContentType $ContentType -WebSession $NetScalerSession -Verbose:$VerbosePreference -ErrorAction SilentlyContinue
#endregion End NetScaler NITRO Session
}

# Altering the size of the PS Buffer
$PSWindow = (Get-Host).UI.RawUI
$WideDimensions = $PSWindow.BufferSize
$WideDimensions.Width = 400
$PSWindow.BufferSize = $WideDimensions

try {
    Get-NSNamedConnectionInfo -NSIP $args[0] -NSUserName $args[1] -NSUserPW $args[2]
}
catch [System.Management.Automation.ParameterBindingException] {
    Write-Error "Couldn't bind parameter exception, Please make sure to provide all necessary parameters"
}