Invoke-WebReqeust Caching Website

PowerShell Help
1

Hi all,

i am writing a script to test a specific ADFS URL. (Federated Metadata). The way the script works is it firsts adds an entry to the Local computers hosts file with IP Address and Name and then uses Invoke-Webrequest to access the site and see if it responds.

this works fine, However if i provide multiple IP Addresses to test where the first IP is correct and the second IP is incorrect, Invoke web request still passes with a response of 200. although the website cannot be reached on the second IP address.

something is caching. how do i clear the Invoke-Webrequest cache

I have already tried the

-Headers @{"Cache-Control"="no-cache"}



$FederatedMetadata = Invoke-WebRequest "https://$($ADFSNameSpace)/FederationMetadata/2007-06/FederationMetadata.xml" -Headers @{"Cache-Control"="no-cache"}
if($FederatedMetadata.StatusCode -eq "200"){
Write-Host "Connection successful to https://$($ADFSNameSpace)/FederationMetadata/2007-06/FederationMetadata.xml" -ForegroundColor Green
$EXTFederatedMetadataTest = "PASS"
}#END_IF
else{
Write-Host "Connection Failed to https://$($ADFSNameSpace)/FederationMetadata/2007-06/FederationMetadata.xml" -ForegroundColor RED
$EXTFederatedMetadataTest = "FAIL"
}#END_ELSE

any suggestions would be greatly appreciated

Thanks

2

Hi Guys,
i have found a work around for the above issue. for anyone who faces this problem in the future.
you can use invoke-command

 $FederatedMetadata  = invoke-command -ComputerName localhost -ScriptBlock {Invoke-WebRequest https://$($args[0])/FederationMetadata/2007-06/FederationMetadata.xml  -TimeoutSec 5} -ArgumentList $($ADFSNameSpace) -ErrorAction SilentlyContinue
 if($FederatedMetadata.StatusCode -eq "200"){
                    Write-Host "Connection successful to https://$($ADFSNameSpace)/FederationMetadata/2007-06/FederationMetadata.xml" -ForegroundColor Green 
                    $EXTFederatedMetadataTest = "PASS"
                }#END_IF    
                else{
                    Write-Host "Connection Failed to https://$($ADFSNameSpace)/FederationMetadata/2007-06/FederationMetadata.xml" -ForegroundColor RED
                    $EXTFederatedMetadataTest = "FAIL"

The above code is able to runs fine when the hosts file is updated

Thanks

3

Can you provide more detail about how you’re setting and removing the IPs from the hosts file?

4

Hi James,
within the script i have two functions Update-HostFileObject and Remove-HostFileObject

Function Update-HostFileObject {
    [cmdletbinding()]
    param(
        [string]$IPAddress,
        [String]$DNSName
    )

    $HostsFile = "$($ENV:systemroot)\System32\drivers\etc\hosts"

    Write-Verbose "[$((get-date).TimeOfDay.ToString()) PROCESS ] Updating: $($IPAddress) $($DNSName) on $($HostFile)"
    "`r$($IPAddress) $DNSName" | Add-Content -PassThru $HostsFile -ErrorAction stop

}

Function Remove-HostFileObject {
    [cmdletbinding()]
    param(
        [string]$IPAddress,
        [String]$DNSName
    )

    $HostsFile = "$($ENV:systemroot)\System32\drivers\etc\hosts"
    $HostFileContent = Get-Content $HostsFile -Raw 

    #Remove HostFile Entry
    if($HostFileContent -match "$($IPAddress) $($NSName)"){

     Write-Verbose "[$((get-date).TimeOfDay.ToString()) PROCESS ] Removing: $($IPAddress) $($DNSNAme) from $($HostFile)"
    $UpdatedHostFile = $HostFileContent -replace "$IPAddress $DNSName"
    Clear-Content $HostsFile
    $UpdatedHostFile | Add-Content $HostsFile -ErrorAction stop

    } #ENDIF
    else{
        Write-Host "Host entry $($IPAddress) $($DNSName) not found"
    }
    
}