iisInstaller.ps1

param (
    #folder where all your websites are located
    [string]$webSiteRootFolder = "c:\\websites",
    #name of site that you're setting up
    [string]$siteName = "HelloWorld",
    #the port your default binding is using
    [string]$port = 8090
)
    

import-module WebAdministration



#site folder
$siteInstallLocation = "$webSiteRootFolder\\$siteName"

#site application pool
$siteAppPool = "$siteName-pool"

#check if the site is already present (determines update or install)
$isPresent = Get-Website -name $siteName 

if($isPresent){
   #upgrade the current package

    Write-Host "$siteName will be updated"
    Copy-Item "source/*" -Recurse $siteInstallLocation -Force
}else{
    #install a clean version of the package

    Write-Host "$siteName will be installed"

    #create site folder
    new-item $siteInstallLocation -ItemType directory -Force

    #copy site files to site folder
    Copy-Item "source/*" -Recurse $siteInstallLocation -Force

    #create application pool
    New-WebAppPool -Name $siteAppPool -Force

    #set the alwaysRunning setting to true.(this is needed for workflow to start properly)
    #to find which path to modify look in the applicationHosts.config file (google for location)
    Set-WebConfigurationProperty "/system.applicationHost/ApplicationPools/add[@name='$siteAppPool']" -PSPath IIS:\ -Name startMode -Value "AlwaysRunning"

    #create site
    New-Website -Name $siteName -Port $port -ApplicationPool $siteAppPool -PhysicalPath $siteInstallLocation

}