Warmup-WebApp is a PowerShell script that can invoke a list of pages in the front-end and even call operations of WCF services to make sure all required initialization and caching is ready and worker processes are started. Please note that this script will only work on PowerShell 3.0+

Warmup-WebApp.ps1

#Parameters
$logFolder = "C:\Temp\logs"
$logFile = "$logFolder\Warmup_$(Get-Date -Format "MM-dd-yyyy_hh-mm-ss").log"
$timeoutSec = 10
$headers = @{
    SOAPAction= "";
    "Accept-Encoding" = "gzip,deflate";
    "User-Agent" = "PowerShell/Warmup-WebApp"
}
$webRequests = @(
    @{
        SOAPAction = "http://tempuri.org/IService1/Operation1";
        Body = @"
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:tem="http://tempuri.org/">
   <soapenv:Body>
      <tem:Operation1>
         <tem:Parameter1>1</tem:Parameter1>
         <tem:Parameter2>2</tem:Parameter2>
      </tem:Operation1>
   </soapenv:Body>
</soapenv:Envelope>
"@
    },
    @{
        SOAPAction = "http://tempuri.org/IService1/Operation2";
        Body = @"
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:tem="http://tempuri.org/">
   <soapenv:Body>
      <tem:Operation1>
         <tem:Parameter1>1</tem:Parameter1>
         <tem:Parameter2>2</tem:Parameter2>
      </tem:Operation1>
   </soapenv:Body>
</soapenv:Envelope>
"@
    } 
)

# Functions
function Write-Log([string]$level, [string]$text) {
	$logTime = Get-Date -Format "yyyy-MM-dd HH:mm:ss.fff"
	Write-Host "[$level] $text"
    if ($logFile -ne $null) {
        "$logTime [$level] $text" | Out-File -FilePath $Logfile -Append
    }
}
function Cleanup-LogFiles() {
    $expiryDate = (Get-Date).AddMinutes(-7)
    [bool]$logFileDeleted = $false
    $filesToDelete = Get-Childitem $logFolder -Include "*.log" -Recurse | ? {$_.LastWriteTime -le $expiryDate} | % {
        Remove-Item $_.FullName | out-null
        Write-Log "Information" "File deleted successfully - $_"
        $logFileDeleted = $true
    }
    if (-not $logFileDeleted) {
        Write-Log "Information" "No old log file was found in $logFolder"
    }
}
function Warmup-WcfService($serviceUrl) {
    foreach($webRequest in $webRequests) {
        $headers["SOAPAction"] = $webRequest.SOAPAction
        Invoke-WcfService $serviceUrl $headers $webRequest.Body
    }
}
function Invoke-WcfService($uri, $headers, $body) {
    $invocationStartTime = Get-Date
    try {
        $result = Invoke-WebRequest -Uri $uri -Method Post -UseDefaultCredentials -ContentType "text/xml; charset=utf-8" -Headers $headers -body $body -TimeoutSec $timeoutSec
        $invocationDuration = (Get-Date).Subtract($invocationStartTime)
        if ($result.StatusCode -eq 200) {
            if ($result.Headers.ContainsKey("Content-Length")) {
                $contentLength = $result.Headers["Content-Length"]
            } else {
                $contentLength = "$($result.RawContentLength) (raw)"
            }
            Write-Log "Information" "WCF operation invoked successfully - Operation: $($webRequest.SOAPAction)($variation), Duration: $($invocationDuration), Length: $contentLength"
        } else {
            Write-Log "Warning" "WCF operation failed - Operation: $($webRequest.SOAPAction)($variation), Status: $($result.StatusCode) $($result.StatusDescription), Length: $contentLength"
        }
    } catch {
        Write-Log "Critical" "WCF operation failed - Operation: $($webRequest.SOAPAction)($variation), Exception: $_"
    }
}
function Invoke-WebPage([string]$uri, [bool]$getImages, [bool]$getScripts) {
    try {
        $response = Invoke-WebRequest -Uri $uri -UseDefaultCredentials -TimeoutSec $timeoutSec -Proxy "http://localhost" -ProxyUseDefaultCredentials
        if ($response.StatusCode -eq 200) {
            Write-Log "Information" "Web page invoked successfully - URL: $uri, Images: $($response.Images.Count), Scripts: $($response.Scripts.Count), Links: $($response.Links.Count)"
        } else {
            Write-Log "Warning" "Web page invocation failed - URL: $uri, Status: $($response.StatusCode) $($response.StatusDescription)"
        }
    } catch {
        Write-Log "Critical" "Web page invocation failed - URL: $uri, Exception: $_"
    }

    if ($getImages) {
        Fetch-Resources $uri ($response.Images | ? { $_.src } | % { $_.src })
    }

    if ($getScripts) {
        Fetch-Resources $uri ($response.Scripts | ? { $_.src } | % { $_.src })
    }
}

Function Fetch-Resources($baseUrl, $resources) { 
 	[uri]$uri = $baseUrl 
 	$rootUrl = $uri.Scheme + "://" + $uri.Authority 
 	
 	$counter = 0 
 	foreach ($resUrl in $resources) { 
 		if ($resUrl.StartsWith("http", [System.StringComparison]::OrdinalIgnoreCase)) { 
 			$fetchUrl = $resUrl
 		} elseif (!$resUrl.StartsWith("/")) { 
 			$fetchUrl = $rootUrl + "/" + $resUrl 
 		} else {
      $fetchUrl = $rootUrl + $resUrl
    }
 
 		# Progress 
 		Write-Progress -Activity "Opening " -Status $fetchUrl -PercentComplete (($counter/$resources.Length)*100) 
		$counter++ 
 		 
 		# Execute 
        try {
 		    $resp = Invoke-WebRequest -UseDefaultCredentials -UseBasicParsing -Uri $fetchUrl -TimeoutSec 120 
            Write-Log "Information" "Resource has been downloaded successfully - URL: $fetchUrl"
        } catch {
            Write-Log "Warning" "Resource failed to download - URL: $fetchUrl, Exception: $_"
        }
    } 
 	Write-Progress -Activity "Completed" -Completed 
} 

# Execution
Write-Log "Information" "My Web Application Warmup Script - $(Get-Date)"
Write-Log "Information" "Cleaning up old log files..." 
Cleanup-LogFiles
Write-Log "Information" "Warming up WCF Services..."
Warmup-WcfServices
Write-Log "Information" "Warming up Front-End..."
Invoke-WebPage "http://domain.com/area1/Page1.aspx" $true $true
Invoke-WebPage "http://domain.com/area1/Page2.aspx" $true $true
Write-Log "Information" "My Web Application Warmup Script Completed."