Power WebPart 3.0 – Runas-System

In general code in SharePoint runs with the privileges of the current user, but sometimes you need to run code with elevated privileges. The SharePoint object model covers this scenario with the SPSecurity.RunWithElevatedPrivileges. In Power WebPart you can use the “Runas-System” function to run script with elevated privileges. Usage: Runas-System –script

Example 1: Output Current Identity

function render($writer)
{
   $identiy1 = [System.Security.Principal.WindowsIdentity]::GetCurrent().Name
   $identiy2 = Runas-System "[System.Security.Principal.WindowsIdentity]::GetCurrent().Name"

   $writer.Write($identiy1)
   $writer.Write($identiy2)
}

Example 2: Call a Function with Parameters

function Render-Identity($writer)
{
    $identity = [System.Security.Principal.WindowsIdentity]::GetCurrent().Name
    $writer.Write($identity)
}  
function render($writer)
{
   Render-Identity $writer
   Runas-System "Render-Identity `$writer"
}

Example 3: Call a Function with Return Value

function Get-Identity
{
    return [System.Security.Principal.WindowsIdentity]::GetCurrent().Name 
}

function render($writer)
{
   $identity1 = Get-Identity
   $identity2 = Runas-System "Get-Identity"

   $writer.Write($identity1)
   $writer.Write($identity2)
}

Example 4: Impersonate SPWeb

function render($writer)
{
   $writer.Write($web.CurrentUser.LoginName)

    $impersonatedWeb = Runas-System "Get-SPWeb $($web.Url)"
    $writer.Write($impersonatedWeb.CurrentUser.LoginName)
    $impersonatedWeb.Dispose()
}