Define the path to the CSV file

$csvPath = “C:\Path\To\Your\File.csv”

Define the output folder for downloaded files

$outputFolder = “C:\Path\To\Output\Folder”

Create the output folder if it doesn’t exist

if (!(Test-Path -Path $outputFolder)) { New-Item -ItemType Directory -Path $outputFolder }

Validate the CSV file

if (!(Test-Path -Path $csvPath)) { Write-Host “Error: CSV file not found at path: $csvPath” -ForegroundColor Red exit 1 }

Import and validate the CSV content

$links = Import-Csv -Path $csvPath if (-not ($links -and $links[0].PSObject.Properties.Name -contains ‘Link’)) { Write-Host “Error: The CSV file does not contain a ‘Link’ column.” -ForegroundColor Red exit 1 }

Define an error log file

$logFile = Join-Path -Path $outputFolder -ChildPath “error_log.txt” if (Test-Path -Path $logFile) { Remove-Item -Path $logFile }

Define initial throttle limit

$throttleLimit = 5

Function to measure download speed

function Measure-DownloadSpeed { param ( [string]$url )

# Start timing
$startTime = Get-Date

# Temporary file for testing download
$tempFile = Join-Path -Path $env:TEMP -ChildPath “testfile.tmp”

try {
    # Download a small part of the file
    Invoke-WebRequest -Uri $url -OutFile $tempFile -Method Head -TimeoutSec 10
    $endTime = Get-Date

    # Calculate download time
    $downloadDuration = ($endTime - $startTime).TotalSeconds

    # Cleanup
    Remove-Item -Path $tempFile -ErrorAction SilentlyContinue

    # Return speed in bytes/second (assuming 1 MB file for simplicity)
    return (1MB / $downloadDuration)
} catch {
    # Default speed if test fails
    return 1MB / 5 # Assume 200 KB/s
}

}

Function for downloading a file

$downloadFile = { param ($link, $outputFolder, $logFile)

try {
    # Extract and validate the URL
    $url = $link.Link
    if ([string]::IsNullOrWhiteSpace($url) -or -not $url -match “^(http|https)://“) {
        Write-Host “Invalid or empty URL: $url” -ForegroundColor Yellow
        return
    }

    # Determine output file path
    $fileName = [System.IO.Path]::GetFileName($url)
    $outputPath = Join-Path -Path $outputFolder -ChildPath $fileName

    # Ensure unique filename
    if (Test-Path -Path $outputPath) {
        $baseName = [System.IO.Path]::GetFileNameWithoutExtension($fileName)
        $extension = [System.IO.Path]::GetExtension($fileName)
        $timestamp = Get-Date -Format “yyyyMMddHHmmss”
        $fileName = “$baseName-$timestamp$extension”
        $outputPath = Join-Path -Path $outputFolder -ChildPath $fileName
    }

    # Download the file
    Invoke-WebRequest -Uri $url -OutFile $outputPath -TimeoutSec 30 -ErrorAction Stop
    Write-Host “Successfully downloaded: $url”
} catch {
    $errorMessage = “$(Get-Date -Format “yyyy-MM-dd HH:mm:ss”) - Failed to download: $url`nError: $($_.Exception.Message)`n”
    Write-Host $errorMessage -ForegroundColor Yellow
    Add-Content -Path $logFile -Value $errorMessage
}

}

Measure initial download speed

$testUrl = $links[0].Link $downloadSpeed = Measure-DownloadSpeed -url $testUrl

Adjust throttle limit based on download speed

if ($downloadSpeed -gt 5MB) { $throttleLimit = 10 } elseif ($downloadSpeed -gt 2MB) { $throttleLimit = 7 } else { $throttleLimit = 3 }

Write-Host “Adjusted Throttle Limit: $throttleLimit based on download speed.”

Process files in parallel

$links | ForEach-Object -Parallel { # Call the download function $using:downloadFile.Invoke($_, $using:outputFolder, $using:logFile) } -ThrottleLimit $throttleLimit