Function-ValidateCSV.ps1

function import-ValidCSV {
    <#
    .SYNOPSIS
        Imports a CSV file, validating that it has the columns specified in the -requiredColumns parameter.
        Throws a critical error if a required column is not found.

    .NOTES
        IMPORTANT INFORMATION:
        Please always mention the original authors of scripts or script extracts, it helps for traceability, and
        more importantly gives back to Caesar what belong to Caesar ;-)
        
            Author : Jason Coleman
            Role: Californian PowerShell and Virtualization Genius
            Link: https://virtuallyjason.blogspot.com/2016/08/import-validcsv-powershell-function.html

    .LINK
        https://virtuallyjason.blogspot.com/2016/08/import-validcsv-powershell-function.html
    #>

    param
        (
                [parameter(Mandatory=$true)]
                [ValidateScript({test-path $_ -type leaf})]
                [string]$inputFile,
                [string[]]$requiredColumns
        )
        $csvImport = import-csv $inputFile
        $inputTest = $csvImport | gm
        foreach ($requiredColumn in $requiredColumns)
        {
                if (!($inputTest | ? {$_.name -eq $requiredColumn}))
                {
                        write-error "$inputFile is missing the $requiredColumn column"
                        exit 10
                }
        }
        $csvImport
}