Import-Module Install-Patches.psm1 -Force

Install-Patches -Computername DC1

<#
Save this with a .PSM1 extension and use Import-Module to properly load the functions.
ie: Install-Patches.psm1
Import-Module Install-Patches.psm1
#>
#Validate user is an Administrator
Write-Verbose "Checking Administrator credentials"
If (-NOT ([Security.Principal.WindowsPrincipal] [Security.Principal.WindowsIdentity]::GetCurrent()).IsInRole(`
    [Security.Principal.WindowsBuiltInRole] "Administrator"))
{
    Write-Warning "You are not running this as an Administrator!`nPlease re-run this with an Administrator account."
    Break
}

Function Create-UpdateVBS {
Param ($computername)
#Create Here-String of vbscode to create file on remote system
$vbsstring = @"
ON ERROR RESUME NEXT
CONST ForAppending = 8
CONST ForWriting = 2
CONST ForReading = 1
strlocalhost = "."
Set oShell = CreateObject("WScript.Shell") 
set ofso = createobject("scripting.filesystemobject")
Set updateSession = CreateObject("Microsoft.Update.Session")
Set updateSearcher = updateSession.CreateupdateSearcher()
Set updatesToInstall = CreateObject("Microsoft.Update.UpdateColl")
Set searchResult = updateSearcher.Search("IsInstalled=0 and Type='Software'")
Set objWMI = GetObject("winmgmts:\\" & strlocalhost & "\root\CIMV2")
set colitems = objWMI.ExecQuery("SELECT Name FROM Win32_ComputerSystem")
	For Each objcol in colitems
		strcomputer = objcol.Name
	Next
set objtextfile = ofso.createtextfile("C:\" & strcomputer & "_patchlog.csv", True)
objtextfile.writeline "Computer,Title,KB,InstallResultCode"
If searchresult.updates.count = 0 Then
	Wscript.echo "No updates to install."
	objtextfile.writeline strcomputer & ",NA,NA,NA"
	Wscript.Quit
Else
For I = 0 To searchResult.Updates.Count-1
    set update = searchResult.Updates.Item(I)
	    If update.IsDownloaded = true Then
	       updatesToInstall.Add(update)	
	End If
Next
End If
err.clear
Wscript.Echo "Installing Updates"
Set installer = updateSession.CreateUpdateInstaller()
installer.Updates = updatesToInstall
Set installationResult = installer.Install()
	If err.number <> 0 Then
		objtextfile.writeline strcomputer & "," & update.Title & ",NA," & err.number
	Else		
		For I = 0 to updatesToInstall.Count - 1
		objtextfile.writeline strcomputer & "," & updatesToInstall.Item(i).Title & ",NA," & installationResult.GetUpdateResult(i).ResultCode 
		Next
	End If
Wscript.Quit
"@

Write-Verbose "Creating vbscript file on $computer"
Try {
    $vbsstring | Out-File "\\$computername\c$\update.vbs" -Force
    Return $True
    }
Catch {
    Write-Warning "Unable to create update.vbs!"
    Return $False
    }
}


Function Format-InstallPatchLog {
    [cmdletbinding()]
    param ($computername)
    
    #Create empty collection
    $installreport = @()
    #Check for logfile
    If (Test-Path "\\$computername\c$\$($computername)_patchlog.csv") {
        #Retrieve the logfile from remote server
        [array]$CSVreport = Import-Csv "\\$computername\c$\$($computername)_patchlog.csv"
        If ($csvreport[0].title -ne "NA") {
            #Iterate through all items in patchlog
            ForEach ($log in $CSVreport) {
                $temp = "" | Select Computer,Title,KB,InstallResultCode
                $temp.Computer = $log.Computer
                $temp.Title = $log.title.split('\(')[0]
                $temp.KB = ($log.title.split('\(')[1]).split('\)')[0]
                Switch ($log.InstallResultCode) {
                    1 {$temp.InstallResultCode = "No Reboot required"}
                    2 {$temp.InstallResultCode = "Reboot Required"}
                    4 {$temp.InstallResultCode = "Failed to Install Patch"}
                    "-2145124316" {$temp.InstallResultCode = "Update is not available to install"}
                    Default {$temp.InstallResultCode = "Unable to determine Result Code"}            
                    }
                $installreport += $temp
                }
            }
        Else {
            $temp = "" | Select Computer, Title, KB,InstallResultCode
            $temp.Computer = $computername
            $temp.Title = "NA"
            $temp.KB = "NA"
            $temp.InstallResultCode = "NA"  
            $installreport += $temp            
            }
        }
    Else {
        $temp = "" | Select Computer, Title, KB,InstallResultCode
        $temp.Computer = $computername
        $temp.Title = "NA"
        $temp.KB = "NA"
        $temp.InstallResultCode = "NA"  
        $installreport += $temp      
        }
    Write-Output $installreport
}

Function Install-Patches {
<#    
.SYNOPSIS    
    Install patches on a local or remote computer and generates a report.
.DESCRIPTION  
    Install patches on a local or remote computer and generates a report with status of installation.
.PARAMETER Computername  
    Name of the computer to install patches on.           
.NOTES    
    Name: Install-Patches 
    Author: Boe Prox  
    DateCreated: 19May2011   
        
.LINK    
    https://boeprox.wordpress.com  
.EXAMPLE    
    Install-Patches -Computername Server1
    
    Description
    -----------
    Installs patches on Server1 and displays report with installation status.

.EXAMPLE    
    Install-Patches -Computername Server1,Server2,Server3
    
    Description
    -----------
    Installs patches on Server1,Server2 and Server3 and displays report with installation status.    
#>
[cmdletbinding()]
Param(
    [Parameter(Mandatory = $True,Position = 0,ValueFromPipeline = $True)]  
    [string[]]$Computername
    )
Begin {
    If (-Not (Test-Path psexec.exe)) {
        Write-Warning "PSExec not in same directory as script!"  
        Break
        }
    }
Process {
    ForEach ($computer in $computername) {
        If ((Test-Connection -ComputerName $computer -Count 1 -Quiet)) {
            Write-Verbose "Creating update.vbs file on remote server."
            If (Create-UpdateVBS -computer $computer) {
                Write-Verbose "Patching computer: $($computer)"
                .\psexec.exe -accepteula -s -i \\$computer cscript.exe C:\update.vbs
                If ($LASTEXITCODE -eq 0) {
                    Write-Verbose "Successful run of install script!"
                    Write-Verbose "Formatting log file and adding to report"
                    Format-InstallPatchLog -computer $computer
                    }            
                Else {
                    Write-Warning "Unsuccessful run of install script!"
                    $report = "" | Select Computer,Title,KB,IsDownloaded,InstallResultCode
                    $report.Computer = $computer
                    $report.Title = "ERROR"
                    $report.KB = "ERROR"
                    $report.IsDownloaded = "ERROR"
                    $report.InstallResultCode = "ERROR" 
                    Write-Output $report
                    }
                }
            Else {
                Write-Warning "Unable to install patches on $computer"
                $report = "" | Select Computer,Title,KB,IsDownloaded,InstallResultCode
                $report.Computer = $computer
                $report.Title = "ERROR"
                $report.KB = "ERROR"
                $report.IsDownloaded = "ERROR"
                $report.InstallResultCode = "ERROR" 
                Write-Output $report
                }
            }
        Else {
            Write-Warning "$($Computer): Unable to connect!"
            } 
        } 
    }   
}
Export-ModuleMember Install-Patches