Goes through the motions to log into umbraco, right click the root node, click "Republish All Content", and then click the button to confirm

clear-umbraco-cache.ps1

# Clear Umbraco Cache
#
# Simulates a set of HTTP  requests that a normal use would do to log into umbraco and clear the global site cache (republish the root node)
#
# == Usage ==
# .\clear-umbraco-cache.ps1 -HostName Hostname -User Username -Pass Password [-UseSsl $false]
#
# == Params ==
# Hostname: Hostname of the server running umbraco
# User / Pass: Valid credentials for an Umbraco User
# UseSSL: (Optional) Enable or Disable SSL (defaults to True)
#
# == Example Usage ==
# .\clear-umbraco-cache.ps1 -HostName dev.americanclubresort.com -User ksykora -Pass #######
#
param ([Parameter(Mandatory=$True)][string]$hostname,
	   [Parameter(Mandatory=$True)][string]$user, 
	   [Parameter(Mandatory=$True)][string]$pass,
	   [bool]$UseSsl = $true)

$MAX_ATTEMPTS = 10
$TIME_BETWEEN_ATTEMPTS_SECONDS = 5

$ErrorActionPreference = "Stop"	   
	   
add-type @"
    using System.Net;
    using System.Security.Cryptography.X509Certificates;
    public class TrustAllCertsPolicy : ICertificatePolicy {
        public bool CheckValidationResult(
            ServicePoint srvPoint, X509Certificate certificate,
            WebRequest request, int certificateProblem) {
            return true;
        }
    }
"@
[System.Net.ServicePointManager]::CertificatePolicy = New-Object TrustAllCertsPolicy

function Clear-UmbracoCache([string]$hostname,
	   [string]$username, 
	   [string]$password,
	   [bool]$ssl = $true) {
	   
	$address = "http{0}://{1}" -f @{$true="s";$false=""}[$ssl], $hostname  
	if(-not $ssl) {
		$sslChar = ""
	}
	#Get login form
	$req = Invoke-WebRequest -Uri "$address/umbraco/login.aspx" -SessionVariable session -TimeoutSec 300
	$attempts = 1
	while(($req.Forms.Length -eq 0 -or (-not $req.Forms[0].Action.EndsWith("login.aspx"))) -and $attempts -le $MAX_ATTEMPTS) {
	#If there was a page returned that didn't include a form, attempt to wait and retry
		Write-Host "attempt $attempts failed. Waiting $TIME_BETWEEN_ATTEMPTS_SECONDS seconds"
		Start-Sleep -Seconds $TIME_BETWEEN_ATTEMPTS_SECONDS
		$req = Invoke-WebRequest -Uri "$address/umbraco/login.aspx" -SessionVariable session -TimeoutSec 300
		$attempts = $attempts + 1
	}
	
	if($req.Forms.Length -eq 0 -or (-not $req.Forms[0].Action.EndsWith("login.aspx"))) {
		throw "Unable to find a form to log into"
	}
	
	$form = $req.Forms[0]

	$form.Fields["lname"] = $username
	$form.Fields["passw"] = $password
		 
	#Submit login form
	$submitLoginRequest = Invoke-WebRequest -Uri "$address/umbraco/login.aspx" -Method "Post" -Body $form.Fields -WebSession $session -TimeoutSec 300
	$form = $submitLoginRequest.Forms[0]
	if(-not $form.Action.EndsWith("umbraco.aspx")) {
		throw "Unable to log in"
	}

	$repubRequest = Invoke-WebRequest -Uri "$address/umbraco/dialogs/republish.aspx" -WebSession $session -TimeoutSec 300

	$form = $repubRequest.Forms[0]
	$form.Fields["ctl00`$body`$bt_go"] = "Republish entire site"

	$response = Invoke-WebRequest -Uri "$address/umbraco/dialogs/republish.aspx" -Method "Post" -WebSession $session -Body $form.Fields -TimeoutSec 300
	
	if($response.Content.Contains("The website cache has been refreshed.")) {
		Write-Host "Cache Cleared"
	} else {
		Write-Host $response
		
		throw "Did not successfully clear cache"
	}
}

Clear-UmbracoCache -hostname $Hostname -username $user -password $pass -ssl $UseSsl


[System.Net.ServicePointManager]::CertificatePolicy = $null