Warm Up SPSites

If we are acting a role as SharePoint 2010 Administrator, now a days it is necessary to explore more knowledge in powershell. Recently we had a requirement in power shell i.e. warming up the sites as it has become daily practice to most of the clients to do so. For this after having google search I got the below info .
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# Title: Warmup-SPSites.ps1
# Author: Ingo Karstein: http://ikarstein.wordpress.com/2011/08/03/sharepoint-warm-up-now-with-timeout/
# Modified by: Wahid Saleemi
# Twitter: @wahidsaleemi
# Reference: http://www.wahidsaleemi.com
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#Region Define Variables
### Setup your variables here
$timeout = 60000 #=60 seconds
# Leave the line below commented if you want all of the Web Apps. Uncomment and set for only specific ones.
#$urls= @("http://finweb", "http://another.sharepoint.local")
#EndRegion
#Region Load SharePoint Snapin
$ver = $host | select version
if ($ver.Version.Major -gt 1) {$Host.Runspace.ThreadOptions = "ReuseThread"}
Add-PsSnapin Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue
#EndRegion


#Region MyWebClient
Add-Type -ReferencedAssemblies "System.Net" -TypeDefinition @"
using System.Net;
public class MyWebClient : WebClient
{
private int timeout = 60000;
public MyWebClient(int timeout)
{
this.timeout = timeout;
}
public int Timeout
{
get
{
return timeout;
}
set
{
timeout = value;
}
}
protected override WebRequest GetWebRequest(System.Uri webUrl)
{
WebRequest retVal = base.GetWebRequest(webUrl);
retVal.Timeout = this.timeout;
return retVal;
}
}
"@
#EndRegion

#Region Function to get Site List
Function Get-SiteList {
$script:sitelist = "$env:temp\siteURLs.txt"
New-Item $script:sitelist -itemType File -Force | Out-Null
# To WarmUp, we really just need the load the Web Apps
$sites = Get-SPWebApplication -IncludeCentralAdministration | Select Url
# If we want to try some caching too, get all the site collections, comment above and uncomment below
# $sites=Get-SPSite -Limit ALL
foreach ($site in $sites)
{
#write-host $site.Url;
$site.Url | Out-File $script:sitelist -append
}
}
#EndRegion
#Region Set URLs to WarmUp
# check to see if a variable $urls is set.
if (!(test-path variable:\urls))
{
Get-SiteList
$urls = (Get-Content $script:sitelist)
}
#EndRegion

#Region Perform the WarmUp
New-EventLog -LogName "Application" -Source "SharePoint Warmup Script" -ErrorAction SilentlyContinue | Out-Null
$urls | % {
$url = $_
Write-Host "Warming up $_"
try {
$wc = New-Object MyWebClient($timeout)
$wc.Credentials = [System.Net.CredentialCache]::DefaultCredentials
$ret = $wc.DownloadString($url)
if( $ret.Length -gt 0 ) {
$s = "Last run successful for url ""$($url)"": $([DateTime]::Now.ToString('yyyy.dd.MM HH:mm:ss'))"
$filename=((Split-Path ($MyInvocation.MyCommand.Path))+"\SPWarmUp.log")
if( Test-Path $filename -PathType Leaf ) {
$c = Get-Content $filename
$cl = $c -split '`n'
$s = ((@($s) + $cl) | select -First 200)
}
Out-File -InputObject ($s -join "`r`n") -FilePath $filename
}
} catch {
Write-EventLog -Source "SharePoint Warmup Script" -Category 0 -ComputerName "." -EntryType Error -LogName "Application" `
-Message "SharePoint Warmup failed for url ""$($url)""." -EventId 1001
$s = "Last run failed for url ""$($url)"": $([DateTime]::Now.ToString('yyyy.dd.MM HH:mm:ss')) : $($_.Exception.Message)"
$filename=((Split-Path ($MyInvocation.MyCommand.Path))+"\lastrunlog.txt")
if( Test-Path $filename -PathType Leaf ) {
$c = Get-Content $filename
$cl = $c -split '`n'
$s = ((@($s) + $cl) | select -First 200)
}
Out-File -InputObject ($s -join "`r`n") -FilePath $filename
}
}
#EndRegion
$script:sitelist | Remove-Item -force -ErrorAction SilentlyContinue