1-30-2017: Using Custom Objects for Fun and Profit

    Custom objects were one of those things I never really saw the point of when I read about them. It wasn't until I actually messed around with them that I really understood their uses. They're especially good for generating reports that pull data from multiple sources.  For example, let's say your manager has requested a report of all the computers in your Accounting department. He wants to know their hostname, their IP Address, their Make/Model, and their Serial Number.  Now, there's no built in function or class (that I know of) that will return all of those pieces of information, so we'll have to pull from multiple data sets.  For this example, we're going to need Active Directory, the Win32_BIOS class, and the Win32_ComputerSystem class. For the sake of argument, let's say we'll also need the Get-CompOU script from the previous post and the hostname of a computer in the Accounting department's OU to get started.
An example asset report script can be downloaded here:
https://goo.gl/5bB03A

Step 1: Generate a list of all the computers needed for this report
$allComps = Get-ADComputer -SearchBase (Get-CompOU AccountingPC1) -filter * -properties * 

      This gives us an array of all the computer objects hosted in the same OU as the Accounting PC we started with. We can get the hostname and IP information just from these objects, but we need more.

Step 2: Enumerate all the computer objects and start data mining
ForEach ($comp in $allComps)
{
        $SWMI = Get-WmiObject -ComputerName $comp.Name -class Win32_ComputerSystem
        $BWMI = Get-WmiObject -ComputerName $comp.name -class Win32_BIOS

We're not quite done with the loop yet, but this shows how we're invoking the WMI classes needed for each computer.  Step 3 takes place within the same loop.

Step 3: Create the custom object to hold our required data
$object = New-Object -TypeName PSObject
$object | Add-Member -MemberType NoteProperty -Name "Hostname" -Value $comp.Name
$object | Add-Member -MemberType NoteProperty -Name "DNSName" -Value $comp.DNSHostName
$object | Add-Member -MemberType NoteProperty -Name "Serial" -Value $BWMI.SerialNumber
$object | Add-Member -MemberType NoteProperty -Name "IPAddress" -Value $comp.IPV4Address  
$object | Add-Member -MemberType NoteProperty -Name "Make" -Value $SWMI.Manufacturer
$object | Add-Member -MemberType NoteProperty -Name "Model" -Value $SWMI.Model 
$allObj += $object
 }
 This one is pretty straight forward. It's a lot of text just to say that you're adding properties to an item you created, assigning those properties values based on multiple classes created in Step 2, and then adding that object to an array of objects.  You can type $allObj = @() at the beginning of your script, but it isn't required.

Step 4: Profit
    At this point, we can dump our report out to a CSV, or we can just output to the screen.  Typing $allObj will just output to the screen, but if we want to make a report our management will be proud of:
$allObj | export-csv -path C:\users\Admin\Documents\AssetReport.csv -NoTypeInformation

And we're done!  Now, if you're working in an environment with SCCM or other management software, these reports might be more easily generated by querying that database. However, this will give you up to the minute accuracy as the WMI queries are done live.  If there's anything you want to see, leave me a comment, and I'll add that to my next post.