This article applies to PRTG Network Monitor 16 or later

I have a lot of users in my PRTG and I'd like to see who's logged in and when we reach peaks. Is that possible?

Introduction

PRTG can't show the currently logged in users, but it's possible with the script below.
Please save it as PRTG-GetLoggedInUsers.ps1 When you just execute it, it will look like this:

Logged in Users within PRTG

The list will allow you to add filter criteria for each column and show all configured users. You can also use it as a PRTG sensor, then it will look something like this:

The script configured as a sensor in PRTG

Installation

1. Save the script as PRTG-GetLoggedInUsers.ps1 to
   %programfiles(x86)%\PRTG Network Monitor\Custom Sensors\EXE
2. Modify the script's parameters according to the table in the Parameters section of this post
3. The script uses Invoke-WebRequest which may lead to PowerShell complaining about the IE not being started yet. The following registry setting will ignore that. Thanks to Daniel Schickmair:
   
   [HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Internet Explorer\Main]
   "DisableFirstRunCustomize"=dword:00000001
4. Create a new EXE/Script Sensor on the Local Probe device
5. Select PRTG-GetLoggedInUsers.ps1 from the EXE/Script dropdown menu
6. Hit Continue The sensor should go green with the next scan, given that all parameters are configured correctly. Otherwise, you'll receive an error stating it could not connect to PRTGs webinterface.

Parameters

Notes

• Please don't configure intervals lower than five minutes as it will lead to performance issues otherwise.

Script

#requires -version 4.0
# ___ ___ _____ ___
#| _ \ _ \_   _/ __|
#|  _/   / | || (_ |
#|_| |_|_\ |_| \___|
# Active PRTG Users
# ================================
# This script will show you the PRTG users that are currently logged in or have logged in today. 
# NOTE: Please don't configure intervals lower than five minutes as it will lead to performance issues otherwise.
#
# Version History
# ----------------------------
# 1.2      Updated to new logging paths of PRTG 18.3.43. Invalid SSL certificates will also work properly now.
# 1.1      Switched to reading users via webinterface. 
# 1.05     Changed search method, now takes 0.14s for every user instead of ~3s in large log files
#          Better debugging output
# 1.01     Updated comments and documentation
# 1.0      initial release
# # # # # # # # # # # # # # # # # # # # # # # # # #
param( 
       [string]$prtgProtocol = "http",
          [int]$prtgPort     = 80, 
       [string]$prtgHost     = "your.prtg.com", 
       [string]$prtgUser     = "prtgadmin", 
       [string]$prtgPasshash = "12345678"
)


function Console-ShowMessage([string]$type,[string]$message){
        Write-Host ("[{0}] " -f (Get-Date)) -NoNewline;
        switch ($type){
            "success"       { Write-Host "    success    "  -BackgroundColor Green      -ForegroundColor White -NoNewline; }
            "information"   { Write-Host "  information  "  -BackgroundColor DarkCyan   -ForegroundColor White -NoNewline; }
            "warning"       { Write-Host "    warning    "  -BackgroundColor DarkYellow -ForegroundColor White -NoNewline; }
            "error"         { Write-Host "     error     "  -BackgroundColor DarkRed    -ForegroundColor White -NoNewline; }
            default         { Write-Host "     notes     "  -BackgroundColor DarkGray   -ForegroundColor White -NoNewline; }
        }
        Write-Host (" {0}{1}" -f $message,$Global:blank) 
}

#region configuration
$progressPreference = 'silentlyContinue'

# ignore invalid ssl certs
add-type @"
using System.Net;
using System.Security.Cryptography.X509Certificates;
public class TrustAllCertsPolicy : ICertificatePolicy {
    public bool CheckValidationResult(
        ServicePoint srvPoint, X509Certificate certificate,
        WebRequest request, int certificateProblem) {
        return true;
    }
}
"@
[System.Net.ServicePointManager]::CertificatePolicy = New-Object TrustAllCertsPolicy


# The list of the users
$Users = New-Object System.Collections.ArrayList;

# We'll need the current date to get the correct log file
[string] $currentDate     = (date -format "yyyyMMdd");

# Extract the correct data path from the registry
[string] $LogFilePath     = ((Get-ItemProperty -Path "hklm:SOFTWARE\Wow6432Node\Paessler\PRTG Network Monitor\Server\Core" -Name "Datapath").DataPath) + "Logs\webserver\WebServer.log"

# Get the content of the log file 
[string[]]$LogFileContent = (Get-Content $LogFilePath);

#endregion

function This-GetLogLines([string]$searchstring){
    
    $Lines = ($LogFileContent -match $searchstring)

    if($Lines) { return $Lines;  }
    else       { return $false; }

}

# This will retrieve all active users from the configuration file and compare them to the webserver log
function This-GetUsers(){

    begin { 
        Console-ShowMessage -type information -message "Using $($LogFilePath)"
        Console-ShowMessage -type information -message "Log is $($LogFileContent.Count) lines long";
        Console-ShowMessage -type information -message "Loading Users..."
    }

    process {
        # uncomment the following line if you've forced TLS 1.2 in PRTGs webinterface
        # [Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12

        # Receive the current PRTG user list   
        try   {$Object = (Invoke-Webrequest -Uri ([string]::Format("{0}://{1}:{2}/config_report_users.htm?username={3}&passhash={4}", $prtgProtocol,$prtgHost, $prtgPort,$prtgUser, $prtgPasshash)) -SessionVariable PRTG)}
        catch { 
            Console-ShowMessage -type error -message "Could not access PRTG webinterface. Please check URL and credentials!";  
            Write-Host "0:Could not access PRTG webinterface. Please check URL and credentials!"    
            #exit 1;  
        }
        
        Foreach($Link in $Object.Links){
            if($Link.OuterHTML -match "edituser.htm" -and [int]$Link.Id)
            { $User = New-Object PSObject –Property @{UserName = $Link.InnerHtml; UserID = $Link.Id}; $Users.Add($User) | Out-Null }
        }
     
           # Get a list of all active users in PRTG - others can't login anyway. 
           Console-ShowMessage -type success -message "Found $($Users.Count) users"; 

           # For every active user in the list ...
           $loggedInUsers = Foreach($User in $Users){

              Console-ShowMessage information "Checking $($User.UserName)"
              #...get the last entry of the user
              $Result = (This-GetLogLines -searchstring "user$($User.UserId)"); 
          
              if($Result)
              { Console-ShowMessage information "$($Result.Length) log entries for this user." -nonewline }
          
              # If the last entry of the user matches logout, he isn't logged in
              $LastEntry = $Result[$Result.Length-1]

              if($LastEntry -match "logout")
              { $LoggedIn = "No" }      

              # If any of the above is not the case, he's logged in. Fill the variables accordingly
              elseif($LastEntry)
              { $LoggedIn = "Yes" }
                        
              if(!($Result)) 
              {   $LoggedIn = "No login today"; $Date = "-"; $Time = "-"; $IP = "-"; }


              $LastEntry = $Result[$Result.Length-1] -split " "
              
              if($LastEntry){ 
                  # fill the variables  with the items from the log line
                  $Date = $LastEntry[1];
                  $Time = $LastEntry[2];
                  $IP   = $LastEntry[3];
              }

              [pscustomobject]@{
                "Last Seen"   = $Time;
                "IP Address"  = $IP
                "User"        = $User.UserName;
                "Logged in"   = $LoggedIn;
              }
           }

        
        # We need this for the PRTG output. It will put all logged in users into an array so we can display them in the sensor message
        $Userlist = @(); 
        $ActiveUsers = ($loggedInUsers | Where-Object -FilterScript {$_.'Logged in' -match "Yes"});
        foreach($ActiveUser in $ActiveUsers){ $Userlist += $ActiveUser.User }
    
    }

    End {
      # If we have the $prtg parameter set, the script will output data using the EXE/Script format (<value>:<message>); 
      if($Userlist.Count -eq 0)    { $UserString = "" }
      else                         { $UserString = "(" + ($Userlist -join ", ") + ")" }
      
      Write-Host ([string]::Format("{0}:{0} user(s) currently logged in {1}",$Userlist.Count,$UserString));
      $loggedInUsers | Out-GridView -Title "[PRTG] Active Users";     
      
    }    
}

This-GetUsers