Tips - Examples of ValidateScript.md

Examples of ValidateScripts

in Scripts, or functions we can use the Powershell Parameter Validation (formally ValidateScript) to validate the entries. Here, some samples of use just for memory.

Syntax

Param(
    [ValidateScript({ScriptBlock})]
    $Var
)

Validating Active Directory computer names

param(
    [ValidateScript({Get-ADComputer -Identity $PSItem})]
    [ValidateNotNullOrEmpty()]
    [string]$ComputerName
)

Validating NetBIOS compatible computer names

This can be useful when:

• You want to work with standalone computers. -You want to create a new virtual machine.

param(
    [ValidateLength(1, 15)]
    [ValidateScript({$PSItem -replace '\\|/|:|\*|\?|"||\||\.' -eq $PSItem})]
    [ValidateNotNullOrEmpty()]
    [string]$ComputerName
)

Validating FQDN compatible computer names

This validates only the name and not the full FQDN.

param(
    [ValidateLength(1, 63)]
    [ValidatePattern('^[a-z0-9-]+$')]
    [ValidateNotNullOrEmpty()]
    [string]$ComputerName
)

Validating full FQDNs

param(
    [ValidateLength(6, 253)]
    [validatePattern('^([a-z0-9]+(-[a-z0-9]+)*\.)+[a-z]{2,}$')]
    [ValidateNotNullOrEmpty()]
    [string]$ComputerName
)

Validating DNS registered computers names

param(
    [ValidateScript({Resolve-DnsName -Name $PSItem})]
    [ValidateNotNullOrEmpty()]
    [string]$ComputerName
)

Validating PowerShell Remoting capable computers

Note This is the same validation you would use for CIM remoting capable computers, except if you force the connection to use DCOM instead.

param(
    [ValidateScript({Test-WSMan -ComputerName $PSItem})]
    [ValidateNotNullOrEmpty()]
    [string]$ComputerName
)

Validating SSH Remoting capable computers

param(
    [ValidateScript({(Test-NetConnection -ComputerName $PSItem -Port 22).TcpTestSucceeded})]
    [ValidateNotNullOrEmpty()]
    [string]$ComputerName
)

Validating SMB capable computers

This can be useful when you want to map a network drive.

param(
    [ValidateScript({(Test-NetConnection -ComputerName $PSItem -CommonTCPPort 'SMB').TcpTestSucceeded})]
    [ValidateNotNullOrEmpty()]
    [string]$ComputerName
)

Validating SQL capable computers

In addition to validating the port availability, it also tries a connection with your current credential.

param(
    [ValidateScript({(Test-DbaConnection $PSItem).ConnectSuccess})]
    [ValidateScript({(Test-NetConnection -ComputerName $PSItem -Port 1433).TcpTestSucceeded})]
    [ValidateNotNullOrEmpty()]
    [string]$ComputerName
)

About Validating a whole list of computer names

See more informations in the following link : https://itluke.online/2020/08/05/validating-computer-names-with-powershell/

Validating Module

Depending on the audience of your function or script, you may want to give a hint when a required module for a validation script attribute is missing.

However, and unfortunately, the #Requires statement is processed after all parameters are validated. And inside a validation script block, the #Requires statement is ignored.

But, as a workaround, you can make a check on your own and throw a terminating error. The second example from the beginning (validating Active Directory computers) could look like:

param(
    [ValidateScript( {
        if (-not(Get-Module -Name 'ActiveDirectory' -ListAvailable)) {
            throw 'The ActiveDirectory module is missing on this computer!'
        }
        else {
            Get-ADComputer -Identity $PSItem
        }
    })]
    [ValidateNotNullOrEmpty()]
    [string]$ComputerName
)

All the previous samples are from the following link : https://itluke.online/2020/08/05/validating-computer-names-with-powershell/

validate a value

Here validate the value is equal to 20

param (
    [ValidateScript({
        if ($_ -eq 20) {
            $true
        }
        else {
            throw "$_ is invalid. Valid value is 20 only."
        }
    })]
    )

Validate Date

• startDate - date must not be older than 90 days. - date must not be in the future.
• endDate - date must not be older than 90 days. - date must not be in the future.

param (
        [ValidateScript({
            ($_ -gt (Get-Date -Hour 0 -Minute 0 -Second 0).AddDays(-90) -and $_ -le (Get-Date))
        })]
        [datetime]$startDate,

        [ValidateScript({
            ($_ -gt (Get-Date -Hour 0 -Minute 0 -Second 0).AddDays(-90) -and $_ -le (Get-Date))
        })]
        [datetime]$endDate
    )

Validate date is greater than the current date

Param(
    [ValidateScript({$_ -ge (Get-Date)})]
)

Validate Existing Process

param (
    [ValidateScript(
            {
                if (Get-Process -Name $_) {
                    $true
                }
                else {
                    throw "A process with name $_ is not found."
                }
            }
        )]
)

Validate if the var is contain on a Set of var

$ValidateSet =   @('Banana','Apple','PineApple') # (Get-Content -Path 'E:\Temp\FruitValidationSet.txt')

function Test-LongValidateSet
{
    Param
    (
        [ValidateScript({
            if ($ValidateSet -contains $PSItem) {$true}
            else { throw $ValidateSet}})]
        [String]$Fruit
    )

    "The selected fruit was: $Fruit"
}

Source : https://stackoverflow.com/questions/56115792/how-to-have-a-powershell-validatescript-parameter-pulling-from-an-array

Validate if a path is existing

Param(
    [ValidateScript({Test-Path $_ })]
    $Path
)

Using an "If" statement with the ValidateScript parameter validation attribute

Function Check-Parameters
{
  [cmdletbinding()]
  Param
  (
    $ComputerName = $env:COMPUTERNAME,
    [Switch]$Param1,
    [ValidateScript({
        If ($Param1)
            {Throw
            "The Param1 parameter and the Param2 parameter cannot be used together!"
            }
        else{$true}})]
    [Int]$Param2
  )
  'Running function with parameters: {0}' -f ($PSBoundParameters.Keys -join ', ')
}
Check-Parameters -Param1 -Param2 "10"
Check-Parameters -Param2 "10"
Check-Parameters -Param1

Ref : https://powershell.org/forums/topic/using-an-if-statement-with-the-validatescript-parameter-validation-attribute/

Useful links and references

https://adamtheautomator.com/powershell-validatescript/ https://jdhitsolutions.com/blog/powershell/2193/powershell-scripting-with-validatescript/ https://powershell.org/2013/05/why-doesnt-my-validatescript-work-correctly/