PowerShell: WMI to Report Installed Applications on Remote Systems

Recently, I've been working with more PowerShell Remoting. Earlier this week I wrote a script that queries a list of systems for installed applications using Remoting. Tomorrow, I'm demo'ing that script (which I will post after this one) and needed to show how you would do it using just WMI in PowerShell. Since the listing of installed applications is stored in the Registery it took a good amount of time trying to figure out how to access a remote registry via PowerShell just using WMI. Below is the comparison script. Enjoy.

#########################################################
# Script Name: PS_Remote_WMI_Installed_Applications.ps1
# Version: 1.0
# Description: Using WMI Remotely Queries
#               Systems for Installed Software
#########################################################

#Array for Reporting Installed Software
$installedApps = @();

#Array for Registry Paths to Installed Apps
$appRegPaths = @("Software\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall",
                 "Software\Microsoft\Windows\CurrentVersion\Uninstall");

#Array of System Names to Run Against
$computers = @("SERVER01","SERVER02","SERVER03");

foreach($computer in $computers)
{
    #Ping System First
    if(Test-Connection -ComputerName $computer -Quiet)
    {
        #Connect to WMI Registry Class
        $uReg = [wmiclass]"\\$computer\root\default:StdRegProv";
                          
        foreach($regPath in $appRegPaths)
        {
            #Pull the Application Registry Keys 
            $iAppKeys = $uReg.EnumKey(2147483650,$regPath);
    
            #Null Check on Application Registry Keys
            if($iAppKeys)
            {
                #Loop Through Each Application Key
                foreach($appKey in $iAppKeys.sNames)
                {
                    #Construct Key Path
                    $keyPath = $regPath + "\" + $appKey.ToString();
                    
                    #Pull the Key DisplayName String Value
                    $keyDisplayName = $uReg.GetStringValue(2147483650,$keyPath,"DisplayName");
                    if(![string]::IsNullOrEmpty($keyDisplayName.sValue))
                    {
                        #Local Vars Used for Reporting
                        [string]$displayName = $keyDisplayName.sValue.ToString();
                        [string]$displayVersion = "";
                    
                        #Pull the Key DisplayVersion String Value
                        $keyDisplayVersion = $uReg.GetStringValue(2147483650,$keyPath,"DisplayVersion");
                        if(![string]::IsNullOrEmpty($keyDisplayVersion.sValue))
                        {
                            $displayVersion = $keyDisplayVersion.sValue.ToString();
                        }
                
                        #Create Custom PSObject and Add to Reporting Array
                        $app = New-Object PSObject;
                        $app | Add-Member -MemberType NoteProperty -Name "ComputerName" -Value $computer;
                        $app | Add-Member -MemberType NoteProperty -Name "DisplayName" -Value $displayName;
                        $app | Add-Member -MemberType NoteProperty -Name "DisplayVersion" -Value $displayVersion;
                          $installedApps += $app;
                        
                    }#End of Null\Empty Check on DisplayName String Value
                    
                }#End of Foreach $iAppKeys
            
            }#End of Null Check on $iAppKeys
        
        }#End of Foreach Reg Path
    
    }#End of Test-Connection

}#End of Foreach Computer

$installedApps | Sort-Object ComputerName,DisplayName | Format-Table -AutoSize;