Backup-Folder.ps1

# Created by Dallin Hitchcock on January 8, 2019
# Backs up $SourceDirectory or individual files that have been created since midnight
# Creates a zip file of the backups (name format yyyy-MM-dd.zip)
# Copies the zip file to $DestinationDirectory
# If the $KeepLast parameter is specified, only keeps that number of backups in $DestinationDirectory

param (
    [Parameter(Mandatory,ValueFromPipelineByPropertyname)]
    [ValidateNotNullOrEmpty()]
    [string]$SourceDirectory,
    [Parameter(Mandatory,ValueFromPipelineByPropertyname)]
    [ValidateNotNullOrEmpty()]
    [string]$DestinationDirectory,
    [Parameter(Mandatory,ValueFromPipelineByPropertyname)]
    [ValidateNotNullOrEmpty()]
    [string]$TempStore,
    [Parameter(ValueFromPipelineByPropertyname)]
    [ValidateNotNullOrEmpty()]
    [int]$KeepLast,
    [Parameter(ValueFromPipelineByPropertyname)]
    [ValidateNotNullOrEmpty()]
    [string]$FileTypeFilter
)

Import-Module .\Send-SlackErrorMessage.ps1 -Force
function Backup-Folder {
    Try
    {
        $ZipName = (Get-Date).ToString("yyyy-MM-dd") + ".zip"
        # Do the backup
        if (Test-Path $TempStore) { Remove-Item $TempStore -Recurse -Force }
        New-Item -ItemType Directory -Path $TempStore

        if ($FileTypeFilter) {
            # Copy all files in source directory that have been created today
            $BackupFiles = Get-ChildItem $SourceDirectory -Filter $FileTypeFilter -Recurse | Where-Object { $_.CreationTime -gt [datetime]::Today }
            foreach ($ChildFile in $BackupFiles) { Copy-Item -Path $ChildFile.FullName -Destination $TempStore }
        }else {
            # Whole directory recursive copy
            Copy-Item -Path $ChildFile.FullName -Destination $TempStore -Recurse
        }
        
        # Create the zip file in $DestinationDirectory
        Add-Type -AssemblyName System.IO.Compression.FileSystem
        [System.IO.Compression.ZipFile]::CreateFromDirectory($TempStore, "$DestinationDirectory$ZipName")

        # Remove the temp files
        Remove-Item $TempStore -Recurse -Force

        if ($KeepLast) {
            # Only keep the most recent $KeepLast number of backups
            Get-ChildItem $DestinationDirectory -Filter *.zip | Sort-Object LastWriteTime -Descending | Select-Object -Skip $KeepLast | Remove-Item -Force
        }
    }
    Catch
    {
        $ErrorMessage = $_.Exception.Message
        Send-SlackErrorMessage $ErrorMessage
        Break
    }

    if (!$?) {
        # The operation failed with a non-PowerShell exception
        Send-SlackErrorMessage "The operation failed with exit code: $LASTEXITCODE"
    }
}

Backup-Folder